Mental models database

100 People Love

Paul Graham

Build something 100 people love rather than something 1 million people kind of like. Intensity of need beats breadth of appeal.

7 Powers (Hamilton Helmer)

Hamilton Helmer

The seven — and only seven — sources of durable competitive advantage: Scale Economies, Network Economies, Counter-Positioning, Switching Costs, Branding, Cornered Resource, and Process Power.

BATNA

Roger Fisher / William Ury

Best Alternative to a Negotiated Agreement — your power in any negotiation comes not from persuasion, but from the strength of your walk-away option.

Competition is for Losers

Peter Thiel

Peter Thiel's thesis: every moment spent competing is a moment not spent building something unique. The goal is to escape competition entirely.

Disagree and Commit

Once a decision is made after genuine debate, everyone — including dissenters — commits fully to execution. Solves the paralysis of consensus-seeking.

Disruptive Innovation

Clayton Christensen

Inferior products in niche markets that improve until they overtake incumbents.

Distribution

How products reach customers matters more than the product itself.

Lollapalooza Effects

Charlie Munger

When multiple cognitive biases or forces act in the same direction simultaneously, the combined effect isn't additive — it's multiplicative. Recognising these confluences is essential for predicting extreme outcomes.

Do Things That Don't Scale

Paul Graham

The best startups are built through unscalable, hands-on work first.

Extreme Ownership

Jocko Willink

Leaders own everything in their world — no excuses, no blaming subordinates.

Forcing Function

Constraints deliberately introduced to compel desired behaviour.

Founder-Market Fit

Chris Dixon

The founder's unique fit to the problem determines startup success more than any other factor.

Growth vs Fixed Mindset

Carol Dweck / Claudia Mueller

Abilities develop through effort and learning, not innate talent alone.

Availability Heuristic

Kahneman & Tversky

We judge the likelihood of events based on how easily examples come to mind, not on actual frequency. Dramatic, recent, or emotionally vivid events get massively overweighted.

Hook Model

Nir Eyal

The four-phase cycle that builds habitual product usage.

Innovator's Dilemma

Clayton Christensen

Good management is the reason great companies fail when disruption arrives.

Iteration Velocity

John Boyd

The team that learns fastest wins — speed of iteration is the ultimate advantage.

Jobs to Be Done

Clayton Christensen

People hire products to accomplish specific functional, emotional, and social jobs.

Luck Surface Area

Jason Roberts / Seneca / Louis Pasteur / Naval Ravikant

Increase exposure to serendipity by doing more and telling more people.

MVP

Frank Robinson / Steve Blank / Eric Ries

The smallest thing that tests your riskiest assumption.

Moats

Warren Buffett / Hamilton Helmer

Durable competitive advantages that protect long-term profitability from competitive erosion.

Asymmetric Payoffs

Nassim Nicholas Taleb

Seek situations where the upside is uncapped and the downside is limited. The expected value of a decision depends not just on probability but on the magnitude of outcomes in each direction.

Network Effects

Robert Metcalfe

Value increases with each additional user, creating exponential competitive advantage.

Platform Business Model

Sangeet Paul Choudary / Geoffrey Parker / Marshall Van Alstyne

Connect distinct user groups and create value through network orchestration.

Porter's 5 Forces

Michael Porter

Some industries print money. Others burn it. The difference is rarely about the talent inside the companies or the quality of their products. It is about the structure of the...

Product/Market Fit

Andy Rachleff / Marc Andreessen

When customers buy faster than you can build — the only thing that matters.

Red Queen Effect

Leigh Van Valen

You have to run as fast as you can just to stay in the same place. In competitive environments, standing still means falling behind because everyone else is improving.

Asymmetric Risk

Nassim Nicholas Taleb

Not all risks are equal. Some decisions carry small downside with enormous upside; others carry catastrophic downside with modest upside. The shape of the risk matters more than its probability.

Pygmalion Effect

Robert Rosenthal / Lenore Jacobson

High expectations create high performance through self-fulfilling prophecy.

Positioning

Michael Porter / Al Ries & Jack Trout

Where you compete matters more than how hard you compete. Choosing the right strategic position — the intersection of your strengths, customer needs, and competitive gaps — determines most of the outcome.

Radical Candor

Kim Scott / Sheryl Sandberg

Care personally and challenge directly — feedback that builds trust and drives improvement.

Reversible vs Irreversible Decisions

Jeff Bezos

One-way doors demand deliberation. Two-way doors demand speed.

Choosing Important Problems

Richard Hamming

The most important decision in any career or research agenda is which problems to work on. Working hard on the wrong problem is worse than working moderately on the right one.

Simplify

Simplification is the ultimate sophistication and competitive advantage.

Start With Why

Simon Sinek

Communicate purpose before product — people buy why you do it, not what you do.

Strategy vs Tactics

Roger Martin

Strategy decides where to play. Tactics decide how to execute.

Sustainable Competitive Advantage

Michael Porter

Advantages that persist because competitors cannot easily replicate them.

Switching Costs

The higher the cost of leaving, the stronger the moat.

Two Pizza Rule

Jeff Bezos / Frederick Brooks

Small autonomous teams outperform large ones — keep teams feedable by two pizzas.

Viral Marketing

Sabeer Bhatia / Jack Smith

When each user brings more than one new user, growth becomes exponential.

Zero to One

Peter Thiel

Create something new rather than copying what exists — aim for monopoly, not competition.

Abstraction

Edsger Dijkstra

Hide complexity behind simpler interfaces to reason at higher levels.

Explore-exploit Tradeoff

Balance gathering new information against leveraging what you already know.

Metcalfe's Law

Robert Metcalfe / George Gilder

Network value grows proportionally to the square of connected users.

Moore's Law

Gordon Moore / Carver Mead

Transistor counts double every two years, driving exponential computing gains.

Mythical Man Month

Frederick P. Brooks Jr.

Adding people to a late project makes it later.

Technical Debt

Ward Cunningham

Expedient decisions create compounding costs that must be repaid.

Barriers to Entry

Joe Bain / Michael Porter

Structural obstacles preventing new competitors from entering a market.

Collective Action Problem

Mancur Olson

Individual incentives to free-ride undermine cooperation for shared benefit.

Comparative Advantage

David Ricardo

Specialize where your opportunity cost is lowest, not where you are best.

Creative Destruction

Joseph Schumpeter

Innovation destroys established industries to create new, more valuable ones.

Economies of Scale

Larger scale drives lower unit costs, creating compounding cost advantages.

First-Mover

Marvin Lieberman / David Montgomery

Being first creates switching costs and brand recognition but bears exploration risk.

Game Theory

John von Neumann / Oskar Morgenstern

Strategic interaction where outcomes depend on all participants choices.

Increasing Returns

W. Brian Arthur

Early advantages compound through positive feedback into winner-take-most outcomes.

Information Asymmetry

George Akerlof

Unequal information between parties creates adverse selection and moral hazard.

Jevons Paradox

William Stanley Jevons

Efficiency improvements increase total consumption rather than reducing it.

Moral Hazard

Kenneth Arrow

Insulation from consequences encourages excessive risk-taking.

Nash Equilibrium

John Nash

No player can improve by unilaterally changing strategy.

Opportunity Cost

Frédéric Bastiat

The true cost of any decision is what you gave up to get it.

Prisoner's Dilemma

Merrill Flood / Melvin Dresher / Albert Tucker

Individual self-interest produces worse outcomes than cooperation.

Skin in the Game

Nassim Nicholas Taleb

Decision-makers must bear consequences to align incentives.

Supply and Demand

Prices adjust to balance what producers supply and consumers buy.

The Agency Problem

Adam Smith / Michael Jensen / William Meckling

Agents with different incentives make suboptimal decisions for principals.

Tragedy of the Commons

William Forster Lloyd / Garrett Hardin

Individual self-interest depletes shared resources, harming everyone.

Winner Take All Market

Sherwin Rosen

Small advantages lead to disproportionate concentration of rewards.

Barbell Strategy

Nassim Nicholas Taleb

Concentrate at extremes of safety and risk, avoid the mediocre middle.

Circle of Competence

Buffett & Munger

You have an edge in some domains and not others — and the boundary between the two is where most catastrophic decisions happen. Knowing where your knowledge actually ends, not where your confidence ends, is the single most protective mental model.

Discounted Cash Flow

John Burr Williams

Value equals future cash flows discounted to present value.

Margin of Safety

Benjamin Graham

Buy below intrinsic value to protect against errors and the unforeseen.

5 Whys

Sakichi Toyoda

Ask why five times to find the systemic root cause.

All Models Are Wrong

George Box

Every model simplifies reality; the question is whether it is useful.

Amara's Law

Roy Amara

Overestimate technology short-term, underestimate it long-term.

Eisenhower Decision Matrix

Dwight D. Eisenhower

Sort tasks by urgency and importance to focus on what truly matters.

First Principles Thinking

Aristotle / Elon Musk

Strip a problem to its fundamental truths and reason up from there — the antidote to reasoning by analogy.

Goodhart's Law

Charles Goodhart

When a measure becomes a target, it ceases to be a good measure.

Law of Triviality

C. Northcote Parkinson / Poul-Henning Kamp

Groups spend disproportionate time on trivial issues they understand.

Map vs Territory

Alfred Korzybski

Models are not reality; confusing the two leads to systematic errors.

Occam's Razor

Among competing explanations, prefer the simplest one.

Paradigm Shift

Thomas Kuhn

The old framework is replaced by an entirely new way of seeing.

Parkinson's Law

C. Northcote Parkinson

Work expands to fill the time available for its completion.

Principle of Falsification

Karl Popper

A claim is only useful if it can be proven wrong.

Regret Minimization Framework

Jeff Bezos

Decide by asking which choice you would regret least at age 80.

Scientific Method

Observation, hypothesis, experiment, and revision produce reliable knowledge.

Second-Order Thinking

Howard Marks

Think past the immediate effect to the second and third-order consequences.

Deep Work

Cal Newport

Sustained concentration on demanding tasks produces disproportionate value.

Deliberate Practice

K. Anders Ericsson

Structured practice targeting specific weaknesses drives elite performance.

Flow State

Mihaly Csikszentmihalyi

Optimal consciousness where challenge and skill match produces peak performance.

Spaced Repetition

Hermann Ebbinghaus

Review at expanding intervals to beat the forgetting curve.

Bayes Theorem

Bayes / Price / Laplace / Fisher

Update your beliefs proportionally to how surprising the new evidence is — the foundation of rational inference.

Black Swan Theory

Nassim Nicholas Taleb

Rare, unpredictable events with extreme impact shape history.

Compounding

Einstein

Exponential growth from consistent small gains over long time horizons.

Correlation vs Causation

Moving together does not mean one causes the other.

Ergodicity

What works across many simultaneously may not work for one across time.

Exponential Growth

Growth accelerates proportionally to current size, slow then explosive.

Fermi Problem

Enrico Fermi

Break impossible questions into tractable sub-problems for useful estimates.

Global & Local Maxima

The best nearby outcome may trap you from reaching the best possible outcome.

Inversion

Carl Jacobi / Charlie Munger

Think backwards: instead of asking how to succeed, ask what guarantees failure — then avoid it.

Kelly Criterion

John Kelly Jr.

Optimal bet sizing maximizes long-term wealth growth while avoiding ruin.

Nonlinearity

Outputs not proportional to inputs; small changes can produce massive effects.

Power Law Distribution

Vilfredo Pareto

A small number of items account for a disproportionate share of outcomes.

Probabilistic Thinking

Thomas Bayes / Nate Silver

Replace binary judgments with probability estimates under uncertainty.

Probability Theory

Pascal / Fermat / Kolmogorov

The mathematical framework for quantifying uncertainty.

Regression to the Mean

Francis Galton

Extreme outcomes are followed by more moderate ones as luck fades.

Signal vs Noise

Claude Shannon

Distinguish meaningful information from irrelevant data.

Asymmetric Warfare

Andrew Mack / Ivan Arreguín-Toft

Weaker forces use unconventional tactics to neutralize stronger opponents.

Blitzkrieg

Heinz Guderian

Concentrated rapid attack at the point of greatest vulnerability.

Fabian Strategy

Quintus Fabius Maximus

Avoid decisive battle to exhaust a stronger opponent through patience.

Fog of War

Carl von Clausewitz

Incomplete information makes reality impossible to see clearly in real time.

Mission Command

Specify intent and objectives; leave tactical execution to those closest.

Mutually Assured Destruction

Robert McNamara

Both sides can inflict unacceptable damage, making conflict irrational.

OODA Loop

John Boyd

Cycle through observe-orient-decide-act faster than competitors.

Red Team

Paul Van Riper

Structured adversarial challenge from the opponents perspective.

Scorched Earth

Destroy resources to deny them to an advancing adversary.

Trojan Horse

Embed offensive capability inside something targets willingly accept.

Adaptation & Red Queen Effect

Leigh Van Valen

Continuous adaptation is required just to maintain relative position.

Complex Adaptive Systems

Murray Gell-Mann

Many interacting agents self-organise to produce emergent behaviour.

Critical Mass

Thomas Schelling

The tipping-point threshold where a process becomes self-sustaining.

Entropy

Rudolf Clausius / Ludwig Boltzmann

All ordered systems tend toward disorder unless energy is continuously invested.

Flywheel

Jim Collins

Self-reinforcing momentum built through consistent effort in one direction.

Incentives

Charlie Munger / Adam Smith

People respond to rewards and punishments, not instructions.

Inertia

Newton / Galileo

Systems resist change proportional to their accumulated mass.

Laws of Thermodynamics

Energy transforms but never appears from nothing — every conversion has a cost.

Leverage (Physics)

Archimedes

A small force at the right point moves disproportionately large loads.

Momentum

Isaac Newton

Mass times velocity — once moving fast and heavy, nearly impossible to stop.

Natural Selection & Extinction

Charles Darwin

Survival belongs to the fit, not the strong — adapt or face extinction.

Newton's Laws

Isaac Newton

Three laws of motion governing force, mass, acceleration, and reaction.

Path Dependence

Paul David / Brian Arthur

Early decisions constrain all future possibilities — history matters.

Systems Thinking

Jay Forrester

Examine interconnections and feedback loops, not isolated components.

Thermodynamics

Every system has an energy budget — ignore the metabolic cost and it dies.

Stoicism

Zeno of Citium / Epictetus / Seneca / Marcus Aurelius

Focus on what you control, accept what you cannot, build virtue.

The Socratic Method

Socrates

Systematic questioning to expose assumptions and clarify thinking.

Thucydides Trap

Thucydides / Graham Allison

Rising power vs ruling power — structural stress makes conflict the default.

Anchoring

Kahneman & Tversky

First information encountered disproportionately shapes all subsequent judgements.

Bandwagon Effect

People adopt trends because others have — popularity self-reinforces.

Bystander Effect

John Darley / Bibb Latané

More witnesses means less action — responsibility diffuses across groups.

Cognitive Dissonance

Leon Festinger

Contradictions between beliefs and actions drive rationalisation over change.

Confirmation Bias

We seek evidence that confirms what we already believe and filter out what contradicts it.

Curse of Knowledge

Colin Camerer / George Loewenstein / Martin Weber

Knowing something makes it impossible to imagine not knowing it.

Decision Fatigue

Shai Danziger / Roy Baumeister

Decision quality deteriorates after sustained choices — willpower is finite.

Dunning-Kruger Effect

David Dunning & Justin Kruger

Low competence breeds overconfidence; expertise breeds doubt.

Endowment Effect

Thaler / Kahneman / Knetsch

Ownership inflates perceived worth beyond objective value.

Framing Effect

Tversky & Kahneman

How you frame the question determines the answer you get.

Fundamental Attribution Error

Lee Ross

We blame character when circumstances are the real cause.

Groupthink

Irving Janis

Cohesive groups suppress dissent and converge on flawed decisions.

Halo Effect

Edward Thorndike

One positive trait colours evaluation of everything else.

Hindsight Bias

Baruch Fischhoff

After the fact, people believe they knew it all along.

IKEA Effect

Michael Norton / Daniel Mochon / Dan Ariely

Labour invested inflates perceived worth regardless of quality.

Incentive-Caused Bias

Charlie Munger

Show me the incentive and I will show you the outcome.

Lollapalooza

Charlie Munger

Multiple biases combining in the same direction produce extreme outcomes.

Loss Aversion

Kahneman & Tversky

Losses hurt roughly twice as much as equivalent gains feel good.

Narrative Fallacy

Nassim Nicholas Taleb

We compress complex reality into clean stories, mistaking explanation for prediction.

Peak-End Rule

Kahneman / Redelmeier / Katz

Experiences are judged by their peak moment and their ending.

Planning Fallacy

Kahneman / Tversky

People systematically underestimate time, cost, and risk of projects.

Self-Fulfilling Prophecies

Robert K. Merton

Beliefs alter behaviour in ways that make the belief come true.

Social Proof

Robert Cialdini

When uncertain, people copy what others are doing.

Status Quo Bias

William Samuelson / Richard Zeckhauser

Loss aversion applied to change makes inaction the default choice.

Sunk Cost Fallacy

Alfred Marshall

Past investments should not drive future decisions.

Survivorship Bias

Abraham Wald

Studying only survivors produces systematically wrong conclusions.

Antifragility

Nassim Nicholas Taleb

Some systems gain from disorder — growing stronger from shocks.

Emergence

Stuart Kauffman / John Holland

Complex wholes arise from simple parts interacting — the whole exceeds the sum.

Feedback Loops

Norbert Wiener / Jay Forrester

Outputs feed back as inputs, creating either amplifying or stabilizing dynamics.

Gall's Law

John Gall

Working complex systems evolve from working simple systems.

Leverage (Systems)

Donella Meadows

Small shifts at the right point produce outsized systemic changes.

Margin of Safety (Systems)

Redundancy and slack let systems absorb unexpected shocks.

Resilience

C.S. Holling

Systems that absorb disturbance and reorganise while maintaining function.

Second-Order Effects

Consequences of consequences often dominate the intended outcome.

Stock and Flow

Stocks accumulate, flows change them — stocks determine behaviour.

Theory of Constraints

Eliyahu Goldratt

Only one constraint matters — optimising anything else is an illusion.

10x Individuals/Teams

Sackman / Erikson / Grant / Steve Jobs / Robert Cringely

In 1968, Sackman, Erikson, and Grant published a study in Communications of the ACM measuring programmer performance on identical tasks. The best performers finished 10 times...

12 Standard Forms of Value

Josh Kaufman

Every business that has ever generated revenue — from a lemonade stand in Phoenix to a $3 trillion company in Cupertino — delivers value in one of twelve fundamental ways. Not a...

5 Parts of Every Business

Josh Kaufman

In 2005, Spanx had one employee, one product, and $10 million in annual revenue. Sara Blakely was creating value (footless pantyhose no one else made), marketing it (cold-calling...

A/B Testing

A/B testing is controlled experimentation applied to product and business decisions. Show half your users a green checkout button and half a red one. Measure which group converts...

AARRR

Dave McClure

Dave McClure stood on a stage in Seattle in 2007 — an Ignite talk, five minutes, twenty slides that auto-advanced every fifteen seconds — and introduced a framework that would...

Ability to Raise Prices

Warren Buffett

Warren Buffett sat in front of the Financial Crisis Inquiry Commission in 2010 and reduced decades of investment philosophy to a single sentence: "The single most important...

Abundance vs Scarcity Mindset

Stephen Covey / Reid Hoffman / Jeff Bezos

Stephen Covey drew the line in 1989. In The 7 Habits of Highly Effective People, he described two fundamentally different orientations toward opportunity. The scarcity mindset...

Active Listening

Carl Rogers / Richard Farson

In 1957, psychologists Carl Rogers and Richard Farson published a short monograph titled Active Listening that introduced a deceptively simple idea: most people do not listen to...

Addressability

Every pitch deck has a TAM slide. Total Addressable Market — that big, round number in the top-right corner meant to signal the size of the opportunity. $50 billion. $120 billion....

Agile

Kent Beck / Ken Schwaber / Jeff Sutherland / Alistair Cockburn / Martin Fowler

In February 2001, seventeen software developers gathered at the Lodge at Snowbird ski resort in Utah. They represented competing methodologies — Extreme Programming, Scrum,...

Amazon Narratives

Jeff Bezos

In 2004, Jeff Bezos sent an email to his senior team banning PowerPoint from Amazon. The replacement: six-page narrative memos, read in silence at the start of every significant...

Attribution Theory

Fritz Heider / Harold Kelley

In 1958, Austrian psychologist Fritz Heider published The Psychology of Interpersonal Relations and proposed something that sounds obvious until you realise how badly most people...

Bait and Switch

Every airline runs the same play. The fare is $49. By the time you've selected a seat, checked a bag, and paid the booking fee, the total is $187. The original price was never the...

Barrier to Competition

Most strategists know about barriers to entry — the obstacles that prevent new players from entering a market. Fewer think carefully about a different and often more important...

Brand

Brand is not a logo. It is not a colour palette, a tagline, or a mission statement printed on a conference room wall. Brand is the sum of associations, expectations, and emotions...

Bullseye Framework

Gabriel Weinberg / Justin Mares

Gabriel Weinberg had a problem. He had built DuckDuckGo — a search engine that competed with Google on privacy — and the product worked. Users who tried it liked it. But users...

Bundling and Unbundling

Jim Barksdale

Jim Barksdale, the CEO who navigated Netscape through the browser wars, told his board something that most business strategists still haven't fully absorbed: "There are only two...

Business Case

A business case is a structured argument for why a proposed initiative deserves resources — time, capital, people. It answers five questions: What is the problem? What is the...

CRM

CRM — Customer Relationship Management — is not software. It is the systematic practice of capturing, organising, and leveraging every interaction with a customer to make the next...

Capital Allocation Options

William Thorndike

Every dollar a business generates faces the same six-way fork: reinvest in existing operations, acquire other businesses, pay down debt, issue dividends, buy back shares, or hold...

Commandos vs Infantry vs Police

Robert X. Cringely

Robert X. Cringely buried one of the sharpest organizational insights of the twentieth century inside a book about the personal computer industry. In Accidental Empires (1992),...

Common Ground

Fisher & Ury

In 1981, Roger Fisher and William Ury published Getting to Yes: Negotiating Agreement Without Giving In and introduced a distinction that should have ended a century of...

Confidence: Speed vs Quality

Jeff Bezos

In his 2016 letter to shareholders, Jeff Bezos made an observation that should be pinned to the wall of every conference room where decisions stall: "Most decisions should...

Consequence vs Conviction

Jeff Bezos

Jeff Bezos drew a 2×2 matrix on a whiteboard at an Amazon all-hands meeting in the early 2010s and changed how the company made every significant decision. One axis measured the...

Core Competency

C.K. Prahalad / Gary Hamel

In 1990, C.K. Prahalad and Gary Hamel published "The Core Competence of the Corporation" in Harvard Business Review and permanently changed how strategists think about competitive...

Costly Signalling Theory

Amotz Zahavi

In 1975, Israeli biologist Amotz Zahavi proposed an idea that turned evolutionary theory sideways. His handicap principle stated that the most reliable signals in nature are the...

Dark Patterns

Harry Brignull

In 2022, the Federal Trade Commission filed a complaint alleging that Amazon had spent years designing its Prime cancellation flow to be deliberately confusing. The internal name...

Diffusion of Responsibility

John Darley / Bibb Latané

In a room of twelve executives, a critical metric is flashing red on the dashboard. Every one of them sees it. None of them acts. Not because they're negligent, and not because...

Directly Responsible Individual

Steve Jobs

Every Monday morning at Apple, the executive team files into a conference room for a three-hour meeting. The agenda covers every significant product, project, and initiative...

Disconfirming Evidence

Darwin / Wason / Munger

Charles Darwin kept a special notebook. Not the famous ones cataloguing finch beaks and barnacle anatomy — a different notebook, dedicated to a single purpose: recording every...

Economically Valuable Skills

Cal Newport

Cal Newport published "So Good They Can't Ignore You" in 2012 and dismantled the most popular career advice of the past fifty years: follow your passion. His counter-argument was...

Expert Problem

Philip Tetlock / Nassim Taleb

Philip Tetlock spent twenty years tracking 28,000 predictions made by 284 experts — political scientists, economists, intelligence analysts, journalists — across domains where...

FOMO Components

In January 2021, GameStop stock rose from $17 to $483 in three weeks. The fundamental value of a struggling brick-and-mortar video game retailer had not changed. What changed was...

FUD

Fear, Uncertainty, and Doubt — FUD — is the competitive strategy of spreading negative, vague, or misleading information about a rival to slow their adoption. The mechanism is not...

Feedback

Kim Scott / Ray Dalio

Every leader knows they should give more feedback. Almost none of them do. The gap between knowing and doing is where organisational dysfunction compounds — silently, invisibly,...

Field Testing

Drew Houston

Focus groups loved New Coke. Two hundred thousand blind taste tests confirmed that consumers preferred the new formula to both old Coke and Pepsi. Coca-Cola launched with total...

Five Fits Framework

Roger Martin & A.G. Lafley

Most companies do not have a bad strategy. They have five disconnected strategies. The product team has a vision. The sales team has a target market. The operations team has a...

Float

Warren Buffett

Float is other people's money that sits in your account before you have to pass it on — and the returns you earn on it in the meantime. The concept is simple. The consequences are...

Fostering Culture

Edgar Schein

Culture is not a mission statement on the wall, a set of values on the careers page, or a foosball table in the break room. Culture is the set of behaviours that get rewarded,...

Founder's Syndrome

Every trait that makes someone a great founder — pathological conviction, breakneck speed, centralised decision-making, appetite for risk that would hospitalise a normal executive...

Framing (Business)

Tversky & Kahneman

How you present information shapes decisions more than the information itself. This is not a psychological curiosity — it is the most leveraged skill in business. The same...

Free

Chris Anderson / Larry Page / Sergey Brin

Free is not the absence of a business model. It is a business model — and in digital markets, it is often the most aggressive competitive weapon available. Chris Anderson's 2009...

Freemium

Fred Wilson

Give the product away for free. Charge for the better version. Venture capitalist Fred Wilson named this model in a March 2006 blog post — "freemium" — and in doing so...

Freeroll

A freeroll is a bet where you cannot lose but might win. The downside is zero or negligible. The upside is real and potentially enormous. The term comes from poker — specifically,...

Gallup Q12

Gallup spent thirty years and 2.7 million employees trying to answer one question: what separates the best workplaces from the worst? The answer was not compensation, perks,...

Gamification

Take the mechanics that make games compulsive — points, levels, badges, leaderboards, progress bars, streaks — and embed them in products that have nothing to do with games. That...

Generalist vs Specialist

Anders Ericsson / Malcolm Gladwell / David Epstein

Two books, published twenty years apart, frame the central tension of human performance. Anders Ericsson's research — popularised in Malcolm Gladwell's Outliers (2008) and...

Heat-seeking Missiles

Andy Rachleff

Andy Rachleff — co-founder of Benchmark Capital and founding CEO of Wealthfront — distilled a pattern he observed across hundreds of venture-backed startups into a metaphor that...

High-context vs Low-context

Edward T. Hall

In 1976, anthropologist Edward T. Hall published Beyond Culture, introducing a framework that divided the world's cultures along a single axis: how much of the message lives...

Horizons Framework

Mehrdad Baghai / Stephen Coley / David White

Every company is running three businesses at once — whether it knows it or not. Horizon 1 is the core: the current business that generates today's revenue and profit. Horizon 2 is...

Hunting Elephants vs Flies

Christoph Janz

Christoph Janz published a blog post in 2014 that became one of the most referenced frameworks in SaaS investing. The title was simple: "Five Ways to Build a $100 Million...

Hype Curve

Jackie Fenn

In 1995, Jackie Fenn — an analyst at Gartner — published a research note that introduced a visual framework for tracking how new technologies evolve in public perception. She...

Idea Maze

Balaji Srinivasan

In 2013, Balaji Srinivasan introduced a concept during Stanford's Startup Engineering course that should have changed how every investor evaluates founders and how every founder...

Improving Returns

Theodore Wright

Most business models suffer from diminishing returns. The first million dollars in revenue is cheap to acquire. The second costs more. The tenth costs dramatically more — because...

Intellectual Property

Intellectual property — patents, trademarks, trade secrets, and copyrights — is the legal architecture that turns ideas into excludable assets. The theory is straightforward: you...

Iron Law of Market

Marc Andreessen / Bill Gross

Marc Andreessen said it plainly in 2007: "The #1 company-killer is lack of market." Not lack of talent. Not lack of capital. Not lack of product vision. Market. The statement is...

Key Failure Indicator

Every company tracks KPIs. Revenue growth, customer acquisition cost, net promoter score, monthly active users — the dashboards glow green when things go well and amber when...

Law of Shitty Click Through Rates

Andrew Chen

In 2012, Andrew Chen published an essay that named something every growth team already felt in their bones but hadn't articulated cleanly. He called it the Law of Shitty Click...

Linear Commerce

Web Smith

In 2018, Web Smith — founder of 2PM Inc. and one of the sharpest voices in digital commerce analysis — published an essay that named a business model most people could feel but...

Listen Decide Communicate

Satya Nadella / Jeff Bezos

The sequence is the model. Listen. Decide. Communicate. Three verbs, fixed order, no substitutions. Most leaders get the ingredients right and the recipe wrong — they decide...

Loss Leader Strategy

King Gillette

Costco sells its rotisserie chicken for $4.99. It has held that price since 2009 despite poultry costs rising over 40%. The company loses approximately $30–40 million per year on...

Marginal Gains

Dave Brailsford

In 2003, Dave Brailsford took over as performance director of British Cycling. The programme was, by any objective measure, a national embarrassment. British riders had won...

Meta-cognition: IQ vs EQ

Daniel Goleman / Peter Salovey / John Mayer / David McClelland / Richard Boyatzis

In 1995, Daniel Goleman published Emotional Intelligence and detonated a quiet bomb under the meritocratic assumption that cognitive horsepower determines who leads and who...

Mind Share

Al Ries / Jack Trout

Mind share is the percentage of consumer awareness or recall that a brand owns within its category. When someone says "search," they think Google. "Electric car" triggers Tesla....

Modularity

Clayton Christensen

Clayton Christensen called it the Law of Conservation of Attractive Profits: when one layer in a value chain becomes modular and commoditised, the adjacent layer becomes integral...

Narrative

Ben Horowitz / Elon Musk

Stories are how humans compress complexity into meaning. A narrative is not decoration layered on top of facts. It is the structure through which facts become intelligible — the...

Nudge Theory

Richard Thaler / Cass Sunstein

A nudge is any element of choice architecture that alters people's behaviour in a predictable way without forbidding any options or significantly changing their economic...

Only Paranoid Survive

Andy Grove

In 1985, Andy Grove was losing. Intel — the company he had co-founded — was haemorrhaging money in the memory-chip business that had defined it since 1968. Japanese manufacturers...

Open vs Closed Platform

In 1981, IBM made a decision that would define the personal computer industry for four decades. Under pressure to ship a PC before Apple ran away with the market, IBM's engineers...

Organisational Debt

Steve Blank

Steve Blank coined the term in a 2015 blog post, and the framing was deliberately borrowed from engineering: organisational debt is the accumulation of changes that leadership...

Perceived Value

Rory Sutherland

A hospital charges $5 for an aspirin tablet. The factory that manufactured it sold the same tablet for $0.03. Same molecule, same dosage, same therapeutic effect — a 167x price...

Peter Principle

Laurence J. Peter

In 1969, Laurence J. Peter published a book that read like satire but operated as diagnosis. The Peter Principle stated a law of hierarchical organisations so simple it felt...

Pivot

Eric Ries / Stewart Butterfield

Eric Ries defined it precisely in The Lean Startup (2011): a pivot is a structured course correction designed to test a new fundamental hypothesis about the product, strategy, or...

Point of Market Entry

Where you enter a market determines your entire strategic trajectory. Not what you build. Not how well you execute. Where you start. The entry point defines which customers you...

Premature Optimisation

Donald Knuth

In 1974, Donald Knuth published "Structured Programming with go to Statements" in Computing Surveys. The paper contained a sentence that would become the most quoted maxim in...

Racecar Growth Framework

Lenny Rachitsky

Lenny Rachitsky spent seven years at Airbnb — the last four leading growth for the supply side of the marketplace, where he was responsible for scaling the host base from tens of...

Remarkability

Seth Godin

Seth Godin published Purple Cow in 2003 with an argument that felt like provocation and turned out to be prophecy: in a world of brown cows, only a purple cow gets noticed. The...

Repeatable Systems

Ray Kroc / Atul Gawande

McDonald's is not in the food business. It is in the systems business. Ray Kroc did not invent the hamburger. He did not invent the french fry, the milkshake, or the drive-through...

Schlep Blindness

Paul Graham

In January 2012, Paul Graham published a short essay that named something every experienced startup investor already knew but had never articulated precisely. Schlep blindness....

Seek Feedback Not Consensus

Jeff Bezos

The distinction is surgical. Feedback is information. Consensus is permission. A leader who seeks feedback is gathering signal to make a better decision. A leader who seeks...

Segmentation

Wendell R. Smith

Not all customers are equal. The sentence sounds obvious — but most companies operate as though it isn't true. They build one product, set one price, run one marketing campaign,...

Servant Leadership

Robert Greenleaf

In 1970, Robert Greenleaf — a retired AT&T executive — published an essay called "The Servant as Leader" that inverted the default assumption about power. The conventional model:...

Shadow Testing

Nick Swinmurn / Drew Houston

In 1999, Nick Swinmurn walked into shoe stores in the San Francisco Bay Area, photographed pairs of shoes on display, listed the photos on a rudimentary website, and waited to see...

Six Sigma

Bill Smith / Jack Welch

In 1986, an engineer at Motorola named Bill Smith had a problem. Motorola's pagers and mobile phones were failing at rates that customers noticed and competitors exploited. The...

Solve Whole Customer Experience

Steve Jobs / Elon Musk

Steve Jobs did not build the best computer. He built the best experience of owning a computer. The distinction is everything. When Jobs returned to Apple in 1997, the company sold...

Span of Control

Lyndall Urwick / Jeff Bezos

How many people can one manager actually manage? The question sounds administrative. It is architectural. The answer determines the shape of the entire organisation — how many...

Strategy Tax

Ben Thompson

Every company has strategic commitments — the core business model, the platform it protects, the revenue engine it depends on, the ecosystem it promised investors it would build....

T-Shaped Employees

Tim Brown / David Guest

Tim Brown, CEO of IDEO, gave the concept its clearest articulation in a 2005 essay for Design Management Journal: the vertical bar of the T is deep expertise in a single...

Team of Teams

Stanley McChrystal

In 2003, General Stanley McChrystal took command of the Joint Special Operations Command in Iraq and discovered that the most capable military force in history was losing to an...

The Third Story

Douglas Stone / Bruce Patton / Sheila Heen

In 1999, Douglas Stone, Bruce Patton, and Sheila Heen — members of the Harvard Negotiation Project — published Difficult Conversations: How to Discuss What Matters Most and...

Three Dimensions of Negotiation

David Lax / James Sebenius

Most people think negotiation is what happens at the table. Two sides, a room, a set of demands, a set of concessions. Anchoring, framing, reading body language, knowing when to...

Time Horizon

Jeff Bezos / Warren Buffett

The length of time over which you evaluate a decision changes which decision is rational. Not which decision feels right. Which decision is right. A $1 billion investment in cloud...

Time Value of Shipping

Brandon Chu / Jeff Bezos

Brandon Chu, VP of Product at Shopify, articulated a principle that experienced operators know intuitively but rarely state with precision: every day you don't ship is a day of...

Trust

Stephen Covey / Warren Buffett

Stephen Covey's The Speed of Trust distilled an observation that every operator knows but few quantify: trust is an economic accelerant. When trust is high, speed goes up and...

Unicorn Candidate

Patrick Collison / Reed Hastings / Steve Jobs

Stripe's internal hiring bar, as Patrick Collison has described it repeatedly, reduces to a single question: "Will this person raise the average quality of the team?" Not meet it....

Unknown Unknowns

Donald Rumsfeld

On February 12, 2002, Donald Rumsfeld stood at a Department of Defense press briefing and delivered a sentence that was mocked, parodied, and ultimately recognised as one of the...

Value Chain Analysis

Michael Porter

A company is not one thing. It is a sequence of activities, each of which adds some portion of the value that customers ultimately pay for — and each of which consumes some...

Value Stream

Taiichi Ohno

In 1950, a Toyota engineer named Taiichi Ohno walked the factory floor and asked a question that would reshape global manufacturing: where does the time actually go? Not the...

Vanity Metrics

Eric Ries

In 2011, Eric Ries published "The Lean Startup" and introduced a term that should have killed the startup pitch deck as we knew it: vanity metrics. A vanity metric is any number...

Visualization

Edward Tufte / Florence Nightingale / Charles Minard

Edward Tufte's central principle is deceptively simple: the best way to understand complex data is to see it. Not to read about it, not to hear it summarised, not to receive a...

Win-Win

Roger Fisher / William Ury

Roger Fisher and William Ury published Getting to Yes in 1981 and changed how the world negotiates. The book's central argument: most negotiations fail not because the parties...

Wisdom of Crowd

Francis Galton / James Surowiecki

In 1906, Francis Galton attended a livestock fair in Plymouth where 787 people paid sixpence each to guess the weight of an ox. Galton — an elitist who believed expertise should...

Black Box

A black box is a system whose internal workings are hidden or irrelevant: you observe inputs and outputs, not mechanism. The term comes from control theory and systems...

Clarke's Third Law

Arthur C. Clarke

Arthur C. Clarke's third law: "Any sufficiently advanced technology is indistinguishable from magic." The line appears in his 1973 revision of Profiles of the Future. The point is...

Constraint Relaxation

Constraint relaxation is a problem-solving move: temporarily drop or loosen a constraint to make a hard problem tractable, then reintroduce the constraint and adapt the solution....

Design Pattern

Gamma / Helm / Johnson / Vlissides

A design pattern is a reusable solution to a recurring problem in a context. The term was popularised in software by the Gang of Four (Design Patterns: Elements of Reusable...

Divide and Conquer

Divide and conquer is a strategy: break a problem into smaller subproblems of the same kind, solve them (often recursively), then combine the solutions. In algorithms, merge sort...

Exponential Backoff

Exponential backoff is a retry strategy: after a failure, wait before retrying, and increase the wait each time — often doubling it (1s, 2s, 4s, 8s, …) until a cap or success. The...

Filter Bubble

Eli Pariser

A filter bubble is an information environment shaped by algorithms (and choices) so that you see more of what you already prefer or believe and less of what would challenge or...

Information Cascade

Bikhchandani / Hirshleifer / Welch

An information cascade occurs when people abandon their private signal and copy the observed actions of others, so that later actors learn nothing from the choices of those before...

Look-Then-Leap Rule

The look-then-leap rule is an optimal stopping strategy: spend a defined phase gathering information (look), then commit when a threshold is reached (leap). It comes from the...

Mechanism Design

Leonid Hurwicz / Eric Maskin / Roger Myerson

Mechanism design is the reverse of game theory: instead of analysing the outcome of given rules, you choose the rules so that self-interested participants are led to an outcome...

Moravec's Paradox

Hans Moravec / Marvin Minsky

Moravec's paradox is the observation that the hard problems for humans are often easy for machines, and the easy problems for humans are often hard for machines. Reasoning,...

Parallel Processing

Parallel processing is doing multiple units of work at the same time instead of one after the other. In computing, it means executing instructions or tasks concurrently across...

Recursion

Recursion is when a process or structure is defined in terms of itself: a function calls itself, a structure contains a smaller instance of the same structure, or a problem is...

Adverse Selection

George Akerlof

In 1970, George Akerlof published "The Market for Lemons," a thirteen-page paper that nearly didn't get published — three journals rejected it as trivial — and that won him the...

Bertrand Paradox

Joseph Bertrand

In 1883, the French mathematician Joseph Bertrand reviewed Antoine Augustin Cournot's work on duopoly theory and identified a devastating implication that Cournot had missed. If...

Bottlenecks

Eliyahu Goldratt

In 1984, an Israeli physicist named Eliyahu Goldratt published a business novel called The Goal. The protagonist, Alex Rogo, manages a failing manufacturing plant. His mentor,...

Coase Theorem

Ronald Coase

In 1937, a 27-year-old British economist named Ronald Coase asked a question that no one in his profession had bothered to answer: why do firms exist? If markets are the most...

Common Knowledge

Robert Aumann / David Lewis

In Hans Christian Andersen's "The Emperor's New Clothes," every citizen privately knows the emperor is naked. The swindlers' con has already failed at the individual level — no...

Competitive Destruction

Warren Buffett once observed that the airline industry has destroyed more shareholder value than it has created since the Wright Brothers flew at Kitty Hawk. That sentence...

Complements & Substitutes

Two products are complements when consuming more of one increases demand for the other. They are substitutes when consuming more of one decreases demand for the other. The...

Conspicuous Consumption

Thorstein Veblen

Thorstein Veblen coined the term "conspicuous consumption" in The Theory of the Leisure Class (1899) to describe spending that signals status rather than satisfies material need....

Counterfactuals

A counterfactual is a "what if" — a scenario that did not happen but could have. "If Kennedy had lived, would the Vietnam War have ended differently?" "If Blockbuster had acquired...

Deadweight Loss

Deadweight loss is the value that disappears when a market is distorted — the trades that would have happened at the equilibrium price but do not happen when a tax, subsidy, price...

Diminishing Utility

The first unit of something you consume gives you more satisfaction than the second. The second gives more than the third. Each additional unit adds less utility than the one...

Division of Labour

Adam Smith / Karl Marx

Adam Smith opened The Wealth of Nations (1776) with a pin factory. One worker making pins from start to finish could produce twenty per day. Ten workers, each specialising in one...

Economic Rent

David Ricardo

Economic rent is income above opportunity cost. David Ricardo defined it in 1817: farmers pay for land's productivity, not the landlord's effort. The landlord collects rent...

Elasticity

How responsive is quantity to price? Price elasticity of demand answers that question with a single ratio: the percentage change in quantity demanded divided by the percentage...

Evolutionarily Stable Strategy

John Maynard Smith

John Maynard Smith introduced the concept in 1973: a strategy that, once adopted by a population, cannot be invaded by an alternative. Game theory meets evolution. An...

Expected Utility Theory

Von Neumann & Morgenstern

Von Neumann and Morgenstern (1944) formalised rational choice under uncertainty: maximise expected utility, not expected value. The formula is Σ (probability × utility). A 50%...

Free-rider Problem

Paul Samuelson

When a benefit is shared and your contribution is hard to observe, the rational move is to contribute nothing and take the benefit anyway. That is the free-rider problem. The good...

Gresham's Law

Sir Thomas Gresham

When two forms of money are legally required to be accepted at the same face value but have different intrinsic values, the bad money circulates and the good money disappears....

Income & Substitution Effects

John Hicks / Roy Allen

When a price changes, demand doesn't just move — it splits. The substitution effect is the shift between goods caused by changed relative prices: as one good becomes cheaper...

Keynesian Beauty Contest

John Maynard Keynes

In The General Theory (1936), John Maynard Keynes described a newspaper contest: readers pick the six prettiest faces from a hundred photos. The prize goes to whoever matches the...

Law of Diminishing Returns

Turgot / Ricardo / Marshall

Adding more of one input, while holding others fixed, eventually yields smaller and smaller increments of output. The first worker on an empty factory floor adds a lot. The...

Marginal Cost/Benefit

Decisions are made at the margin. The question is never "should we do this at all?" in the abstract — it is "should we do one more unit?" Marginal benefit is the extra benefit...

Market Power

Market power is the ability to set price above marginal cost without losing so much volume that the move destroys value. In perfect competition, price equals marginal cost and...

Market for Lemons Problem

George Akerlof

When sellers know more about quality than buyers, and buyers can't tell good from bad before purchase, the market can collapse toward low quality. Sellers of good products can't...

Matthew Effect

Robert K. Merton

The rich get richer; the poor get poorer. Success breeds success; failure compounds. The name comes from the Gospel of Matthew: "For to everyone who has, more will be given; but...

Perfect Competition

Perfect competition is a benchmark: many buyers and sellers, identical products, free entry and exit, full information. No single participant can move price. Each firm faces a...

Positive & Negative Externalities

An externality is a cost or benefit that falls on parties outside a transaction. The buyer and seller do not bear — or do not capture — the full social impact. Negative...

Price Discrimination

Price discrimination is charging different prices to different customers for the same or similar product based on willingness to pay, not cost. The goal is to capture more of the...

Public Goods

Paul Samuelson

A public good is non-rival and non-excludable. Non-rival: your consumption does not reduce mine. Non-excludable: the provider cannot practically exclude non-payers from enjoying...

Ratchet Effect

A ratchet only turns one way. In economics, the ratchet effect is the tendency for levels of effort, cost, or commitment to move up and then stick. Past performance becomes the...

Rent-Seeking

Anne Krueger / Gordon Tullock

Rent-seeking is the use of resources to capture existing value rather than to create new value. Instead of producing more, you try to secure a larger share of what is already...

Resource Curse

Countries rich in oil, minerals, or other extractive resources often grow slower, suffer more corruption, and experience more conflict than resource-poor countries. The resource...

Scarcity (Economics)

Scarcity is the condition that human wants exceed the means to satisfy them. Not everything can be had in unlimited quantity at zero cost; therefore choices must be made....

Social vs Market Norms

Dan Ariely

People operate in two kinds of exchange: social norms and market norms. Social norms are gift-based, relationship-driven, and governed by reciprocity, fairness, and identity. You...

Specialization

Adam Smith

Specialization is the allocation of resources — labour, capital, attention — to a narrow set of activities where they yield more output per unit of input than generalist...

Spillover Effects

Spillover effects are costs or benefits that flow from one activity or decision to parties who are not directly involved in the transaction or choice. A factory's pollution harms...

Sunk Costs (Economics)

Sunk costs are past expenditures of time, money, or effort that cannot be recovered. In economic logic, they are irrelevant to the current decision. What matters is the marginal...

The Experience Curve

Each time cumulative output doubles, unit cost falls by a predictable percentage. That is the experience curve: cost declines as experience accumulates. The effect was quantified...

The Invisible Hand

Adam Smith

Individuals pursuing their own interest can produce collective outcomes that no one intended. Adam Smith called this the invisible hand: self-interested choices, coordinated by...

Thinking at the Margin

Decisions are made at the margin. The relevant question is not "Is this good or bad in total?" but "What happens if I do one more unit, or one less?" Marginal thinking compares...

Tit-for-tat

Robert Axelrod

Cooperate first. Then do whatever the other player did last. That is tit-for-tat: one round of cooperation, then mirror your counterpart's previous move. In repeated games —...

Trade-offs

Every choice surrenders something. Trade-offs are the structure of that surrender: to gain X you give up Y. Economics treats scarcity as the binding constraint — finite resources,...

Transaction Costs

Ronald Coase

Markets do not run for free. Every exchange — buying, selling, contracting, coordinating — consumes resources beyond the nominal price: search, negotiation, enforcement, and the...

Tullock Paradox

Gordon Tullock

When people compete for a fixed prize, they can spend more in the aggregate than the prize is worth. That is the Tullock paradox. Gordon Tullock showed that rent-seeking — the...

Two-sided Market

A two-sided market has two distinct user groups that need each other: buyers and sellers, riders and drivers, advertisers and viewers. The platform sits in the middle and creates...

Ultimatum Game

Werner Güth / Rolf Schmittberger / Bernd Schwarze

One party proposes how to split a fixed pie. The other accepts or rejects. If rejected, both get nothing. Rational self-interest says the responder should accept any positive...

Utility

Utility is the satisfaction or benefit an agent gets from an outcome. It is not directly observable — we infer it from choices. Economists model decision-making as utility...

Winner's Curse

Capen / Clapp / Campbell

In a common-value auction, the object has the same value to everyone, but bidders don't know it. Each bids on an estimate. The winner is the bidder who estimated highest — and...

Zero Price Effect

Dan Ariely

Zero is not just another price. When the price drops from a small positive amount to zero, demand jumps by more than the same-sized drop from a higher price. The zero-price...

Zero vs Positive-Sum

Zero-sum: one party's gain equals the other's loss. The pie is fixed. Positive-sum: the pie can grow; both parties can gain. The distinction shapes strategy, negotiation, and how...

Arbitrage

Arbitrage is profiting from a price difference for the same or equivalent asset across markets, with no net risk. Buy low in one place, sell high in another. The arbitrageur...

Asymmetric Upside

Asymmetric upside is a payoff structure where the best-case gain is large relative to the worst-case loss. You risk a bounded amount to participate in unbounded or outsized...

Cost of Capital

Cost of capital is the minimum return a company or project must earn to justify using investors' money. It is the price of capital — what providers of debt and equity demand for...

Dollar-Cost Averaging

Dollar-cost averaging (DCA) is investing a fixed amount of money at regular intervals regardless of price. You buy more shares when the price is low and fewer when it is high....

Financial Ratios

Financial ratios compress a company's financial statements into comparable, interpretable numbers. They answer questions like: How profitable is this business? How leveraged? How...

Hedging

Hedging is taking an offsetting position to reduce the risk of an existing exposure. You own something that could lose value; you add a position that gains when that thing loses —...

Intrinsic vs Market Value

Intrinsic value is what an asset is worth based on its fundamental ability to generate cash flows or utility — independent of what anyone is willing to pay for it today. Market...

Margin Call

A margin call is the broker's demand that you add collateral or close positions when the value of your margin account falls below the maintenance requirement. You borrowed to...

Mr. Market

Benjamin Graham

Mr. Market is Benjamin Graham's allegory: a manic-depressive partner who shows up every day and offers to buy your share of the business or sell you his at a price. Some days he's...

Option Value

Option value is the worth of the right — but not the obligation — to do something later. In finance, an option pays when the underlying moves in your favour; you can let it expire...

Position Sizing

Position sizing is how much of your capital you put in any single bet. It's not which assets to hold — it's how much. A great idea with 100% of your capital is a single point of...

Risk-Reward Ratio

Risk-reward ratio is the comparison of what you can gain to what you can lose on a bet. If you risk $1 to make $3, the ratio is 1:3 (or 3:1 reward to risk). It doesn't tell you...

Time Value of Money

Time value of money (TVM) is the principle that a dollar today is worth more than a dollar tomorrow. You can invest today's dollar and earn a return; a dollar promised later...

Too Tough Basket

Warren Buffett / Charlie Munger

The too-tough basket is the set of decisions or opportunities you explicitly choose not to make — because they're too hard to evaluate, outside your edge, or not worth the effort....

Domain Dependence

Charlie Munger

Expertise in one field does not automatically transfer to another. Domain dependence is the tendency to apply reasoning, heuristics, and judgment effectively within a familiar...

Efficiency vs Effectiveness

Peter Drucker

Efficiency is doing things right; effectiveness is doing the right things. The distinction is operational: efficiency minimises waste for a given goal (cost per unit, time per...

Epidemic Models

Epidemic models describe how something — a pathogen, a behaviour, a product, an idea — spreads through a population. The core mechanics: contact rate (how often people interact),...

False Cause

False cause is the error of inferring that A caused B when the evidence supports only that A and B are associated. Correlation is not causation: two things can co-occur or move...

False Positives & False Negatives

A test or decision has four outcomes: true positive (correctly say "yes" when the state is yes), true negative (correctly say "no" when the state is no), false positive (say "yes"...

Hanlon's Razor

Robert J. Hanlon

Never attribute to malice that which is adequately explained by incompetence or ignorance. Most bad outcomes come from stupidity, not conspiracy — and assuming malice causes you to misdiagnose the problem.

Hofstadter's Law

Douglas Hofstadter

"It always takes longer than you expect, even when you take into account Hofstadter's Law." Douglas Hofstadter stated this in Gödel, Escher, Bach (1979). The formulation is...

Hypothesis

A hypothesis is a testable claim about the world. Not a wish, not a vision — a proposition that can be disproved by evidence. "If we cut price 10%, volume will rise at least 15%."...

ICE Framework

Sean Ellis

ICE is a prioritisation score: Impact × Confidence × Ease. Rate each dimension (e.g. 1–10), multiply, and rank. High-ICE items get done first. The framework forces you to separate...

Law of Narrative Gravity

Stories pull. Once a narrative takes hold, it attracts evidence, attention, and belief. Facts that fit the story get amplified; facts that don't get discounted or ignored. The law...

Lindy Effect

The longer something has survived, the longer it's likely to survive. That's the Lindy effect. A book that's been in print for 40 years has a longer expected future than a book...

Miles's Law

Rufus Miles

"Where you stand depends on where you sit." Rufus Miles, a federal budget official, said it in the 1940s. Your position — role, department, incentives — shapes your view. The same...

Minimum Effective Dose

The minimum effective dose (MED) is the smallest input that produces the desired outcome. Borrowed from medicine — the lowest dose of a drug that achieves the therapeutic effect —...

Motte and Bailey

Nicholas Shackel

The motte-and-bailey is a rhetorical move: defend an indefensible claim (the bailey) by retreating, when challenged, to a related defensible claim (the motte). The motte is the...

Murphy's Law

Edward Murphy Jr.

Murphy's Law — "anything that can go wrong will go wrong" — is a heuristic for risk and design. Treat it as a design constraint: assume that whatever can fail will fail, and build...

Necessity & Sufficiency

Necessity and sufficiency are the two ways a condition can relate to an outcome. A condition is necessary for an outcome if the outcome cannot occur without it: no A, no B. A...

Observer Effect

The observer effect is the change in a system caused by the act of observing or measuring it. In physics, measuring a particle disturbs it. In human systems, being watched or...

Outcome Blind

Outcome-blind evaluation is judging a decision by the quality of the process and the information available at the time, not by the outcome that followed. A good decision can lead...

Poliheuristic Decision Theory

Alex Mintz

Poliheuristic decision theory describes how people actually choose when stakes are high: a two-stage process. First, they apply a non-compensatory screen — they eliminate any...

Pre-Mortem Analysis

Gary Klein

A pre-mortem is a decision exercise: assume the project or decision has already failed, then work backward to list why. The team imagines it is twelve months later and the launch...

Proxy

A proxy is a stand-in: you use one thing to represent another when the thing you care about is hard to observe or measure directly. Revenue is a proxy for value created; NPS is a...

Punctuated Equilibrium

Eldredge & Gould

Punctuated equilibrium, from evolutionary biology, describes change that is not smooth: long periods of stability are interrupted by short bursts of rapid transformation. Eldredge...

Randomized Controlled Experiment

A randomized controlled experiment (RCT) is the gold standard for learning whether something causes an outcome. You take a population, randomly assign units to treatment (get the...

Replication Crisis

The replication crisis is the discovery that many published research findings do not hold when other researchers try to repeat the same study. In psychology, medicine, economics,...

Revealed Preference

Paul Samuelson

What people say they want and what they actually choose are often different. Revealed preference is the principle that you learn someone's true preferences from their choices, not...

Steelmanning

Steelmanning is the practice of strengthening an opposing argument before engaging it. Instead of attacking the weakest version — the strawman — you build the strongest plausible...

Structure of Scientific Revolutions

Thomas Kuhn

Science does not advance by steady accumulation. It advances in fits: long periods of normal science under a dominant paradigm, then crisis, then revolution. Thomas Kuhn's The...

Sturgeon's Law

Theodore Sturgeon

Ninety percent of everything is crap. Theodore Sturgeon, the science-fiction writer, said it when defending his genre: when people said "90% of science fiction is crud," he...

Systems vs Goals

Scott Adams

Goals are outcomes you want to hit. Systems are the processes you run that make outcomes more likely. The systems-vs-goals frame says: focus on the system. If you run the right...

Thinking Gray

Thinking gray is the discipline of not choosing a side too early. Instead of deciding quickly whether something is good or bad, right or wrong, you hold the possibility that it's...

Tight Coupling

Charles Perrow

Tight coupling means components in a system depend on each other in rigid, time-sensitive ways. When one part fails or lags, the rest cannot adapt; failure propagates quickly and...

Unforced Error

An unforced error is a mistake that was not caused by the opponent or by external pressure — you had the initiative, the information, and the time, and you still failed. The term...

Via Negativa

Nassim Nicholas Taleb

Improvement often comes from subtraction, not addition. Knowing what to remove — bad habits, unnecessary complexity, toxic relationships — is frequently more powerful than knowing what to add.

Wright's Law

Theodore Paul Wright

Wright's Law says that the cost of a unit declines by a consistent percentage every time cumulative production doubles. Theodore Paul Wright formalised it in 1936 for aircraft...

10,000 Hour Rule

Malcolm Gladwell / Anders Ericsson

Expertise takes time. Malcolm Gladwell popularised the idea in Outliers: roughly 10,000 hours of practice separate the exceptional from the merely good. The number came from...

80/20 Rule (Pareto)

Vilfredo Pareto

A small share of causes drives a large share of results. The Pareto principle — the 80/20 rule — states that roughly 80% of outcomes often come from 20% of inputs: 80% of revenue...

Active Recall

Retrieving information from memory strengthens learning more than re-exposing yourself to it. Active recall is the practice of testing yourself — trying to produce the answer, the...

Attention Management

Attention is the bottleneck. You can manage time and still lose the day to fragmentation — meetings, notifications, and context switches that leave little continuous attention for...

Cognitive Load Theory

John Sweller

Working memory is limited. Cognitive load theory (CLT), developed by John Sweller and others, says that learning and performance suffer when the total load on working memory...

Compounding Knowledge

Knowledge can compound. What you learn today makes the next learning easier: new concepts attach to existing ones, patterns repeat across domains, and understanding in one area...

Desirable Difficulty

Robert Bjork

Learning that feels easy often leaves little trace. When retrieval is effortless and conditions match the study environment, the brain encodes superficially. Desirable difficulty...

Feedback Loops (Learning)

Learning requires a loop: act, observe the result, compare to intent, adjust. Without feedback — accurate, timely, and actionable — practice is just repetition. You reinforce...

Feynman Technique

Richard Feynman

If you can't explain it simply, you don't understand it well enough. The Feynman Technique turns that maxim into a method: choose a concept, explain it in plain language as if to...

Grit

Angela Duckworth

Grit is persistence toward long-term goals despite setbacks, boredom, and the temptation to quit. Angela Duckworth defined it in research at the University of Pennsylvania: grit...

Growth Mindset

Carol Dweck

Growth mindset is the belief that ability and intelligence can be developed through effort, strategy, and feedback. Its opposite — fixed mindset — is the belief that ability is...

Habits

Charles Duhigg

A habit is a behaviour that has become automatic — triggered by context or cue with minimal conscious decision. Habits form when a loop is repeated until the brain encodes it: cue...

Interleaving

Interleaving is mixing different types of practice or topics within a session instead of blocking — doing one skill or subject until done, then the next. Blocked practice feels...

Mental Representations

Mental representations are the internal structures you use to perceive, understand, and act on the world. They are not the world itself; they are your compressed, structured model...

Mindfulness

Mindfulness is the practice of attending to present-moment experience with openness and without automatic judgment — noticing what is happening in mind, body, and environment...

Power of Routine

The power of routine is the leverage you get from making repeated behaviours automatic, predictable, and aligned with your goals. Routine reduces decision cost — you don't...

Sleep & Recovery

Sleep and recovery are the processes that restore cognitive, emotional, and physical capacity after load. They are not optional extras; they are the period when the body and brain...

Algorithms

An algorithm is a finite, unambiguous sequence of steps that transforms inputs into outputs. No ambiguity, no infinite loops in the intended design — given the same input, the...

Anti-patterns

An anti-pattern is a recurring solution that looks plausible but backfires: it solves a surface problem while creating worse ones or locking in failure. The term came from...

Apophenia

Klaus Conrad

Apophenia is the tendency to perceive meaningful patterns in random or meaningless data. The brain is a pattern-seeking engine; when it runs on noise, it still finds structure....

Back-of-envelope Calculation

A back-of-envelope calculation is a quick, approximate computation done with minimal tools — napkin, envelope, or mental math — to bound a problem, check an claim, or decide...

Central Limit Theorem

The Central Limit Theorem (CLT) says that the distribution of the sum (or average) of many independent random variables tends toward a normal distribution, regardless of the shape...

Conditional Probability

Conditional probability is the probability of an event given that another event has occurred: P(A|B) = P(A and B) / P(B). It is the workhorse of updating beliefs with evidence....

Confounding Factor

A confounding factor (confounder) is a variable that influences both the supposed cause and the supposed effect, creating a spurious association between them. You see that X and Y...

Gambler's Ruin

Pascal / Huygens

Gambler's ruin is the mathematical certainty that a player with finite capital playing against a house (or opponent) with effectively infinite capital will go broke with...

Inflection Point

Andy Grove

An inflection point is the moment when the rate of change itself changes — the curve stops bending one way and starts bending the other. In calculus, it's where the second...

J-Curve

The J-curve is the shape of outcomes when things get worse before they get better. Performance drops, then recovers and can exceed the starting point — the path traces a "J" when...

Law of Large Numbers

Jacob Bernoulli / Andrey Kolmogorov

The law of large numbers says that as you repeat a random experiment more and more times, the average of the results converges to the expected value. Sample a few times and the...

Law of Small Numbers

Kahneman & Tversky

The law of small numbers is a cognitive bias: we treat small samples as if they were large. We see patterns, stability, and representativeness in a handful of observations where...

Long Tail

Chris Anderson

The long tail is the large number of low-volume items that collectively can match or exceed the sales of the few blockbusters. In a traditional store, shelf space is scarce; you...

Major vs Minor Factors

Major vs minor factors is the discipline of separating what actually moves the outcome from what doesn't. Most outcomes are driven by a few variables; the rest are noise or...

Monte Carlo Fallacy

The Monte Carlo fallacy — also called the gambler's fallacy — is the belief that past independent outcomes change the probability of future ones. A coin that landed heads five...

Monte Carlo Simulation

Stanisław Ulam / John von Neumann

Monte Carlo simulation estimates outcomes by running many random trials instead of solving equations. You define a model (inputs, relationships, and distributions), draw random...

Multiplying by Zero

In a chain of multiplicative factors, one zero makes the product zero. Revenue = traffic × conversion × price × retention. If conversion is zero, revenue is zero no matter how...

Order of Magnitude

Order of magnitude is the size of something expressed as a power of ten. Is it 10, 100, 1,000, or 10,000? Getting the order of magnitude right means you are in the right ballpark...

Outliers

Outliers are observations that lie far from the bulk of the data — the extreme values that don't fit the typical pattern. How you treat them shapes understanding and decisions....

Queuing Theory

Queuing theory is the study of waiting lines: how jobs, requests, or customers arrive, how they are served, and how long they wait. The core result is that wait times and queue...

Randomness

Randomness is the absence of a deterministic pattern: outcomes that cannot be predicted with certainty from prior information. In practice, we treat a process as random when we...

Reference Class Forecasting

Kahneman & Tversky / Bent Flyvbjerg

Reference class forecasting answers a single question: when projects like this one were attempted, what actually happened? Instead of building a bottom-up estimate from tasks and...

Scale

Scale is the relationship between size and outcome: how do cost, performance, or value change as you move from one magnitude to another? The question is not "is bigger better?"...

Scenario Analysis

Pierre Wack

Scenario analysis replaces a single forecast with a small set of distinct futures — typically base, upside, and downside — and asks what happens in each. The goal is not to assign...

Scope Neglect

Paul Slovic

Scope neglect is the failure to adjust judgment or willingness to pay when the scale of the problem changes. People often react similarly to "100 birds at risk" and "10,000 birds...

Sensitivity Analysis

Sensitivity analysis asks: when we change one input, how much does the output change? It identifies which assumptions drive the result. If a 10% drop in conversion rate flips your...

Simpson's Paradox

Edward Simpson / Yule

Simpson's paradox is the reversal of a trend or comparison when data are aggregated versus when they are split into groups. A treatment can look better in every subgroup but worse...

Standard Deviation & Normal Distribution

Standard deviation measures spread: how far outcomes typically are from the average. If the mean is 100 and the standard deviation is 15, then roughly two-thirds of observations...

Alliances

Alliances are formal or informal coalitions formed when the cost of going alone exceeds the cost of sharing gains with others. In conflict and competition, isolated actors rarely...

Appeasement

Appeasement is the strategy of conceding to an adversary's demands in the hope that satisfaction will reduce their aggression. Give them something they want — territory, market...

Arms Races

An arms race is a competitive spiral in which rivals invest in capability to match or exceed each other, driving costs up and often leaving both worse off than before. Each side...

Attrition Warfare

Attrition warfare is the strategy of winning by exhausting the enemy's resources — men, materiel, morale, or capital — until they can no longer continue. Victory goes to the side...

Beachhead

A beachhead is a small, secured position from which to launch a larger advance. In military use, it is the patch of territory seized in an amphibious assault — enough to land...

Brute Force Solution

A brute force solution is one that achieves the objective by applying overwhelming resources rather than by cleverness or efficiency. When you cannot outthink the problem, you...

Burn the Boats

Eliminate retreat so advance is the only option. The image comes from legend: a general lands on hostile shores and orders the fleet burned. No evacuation. No fallback. The army...

Carrot & Stick

Reward and punishment shape behaviour. The carrot induces compliance by offering gain; the stick enforces it by threatening loss. Neither works alone for long. Pure reward without...

Choke Point

A choke point is a narrow passage through which flow must go. Control it and you control the flow. In military terms, it might be a strait, a bridge, or a valley — a place where...

Cold War

A cold war is sustained rivalry without full-scale hot war. Two or more powers compete for influence, territory, and alignment — through proxies, economics, ideology, and arms —...

Containment

Containment is the strategy of limiting a rival’s expansion without seeking total victory. You don’t invade or destroy; you block, resist, and constrain at the edges so that the...

Counterinsurgency

David Galula / Robert Thompson

Counterinsurgency (COIN) is the fight against an insurgency — a weaker party that refuses conventional battle and instead uses hit-and-run, terror, and political mobilisation to...

Defense in Depth

Defense in depth is the use of multiple, layered barriers so that a single failure doesn't compromise the whole. One line breaks; the next holds. The idea is military in origin —...

Deterrence Effect

Deterrence is the use of credible threat to persuade an opponent not to act. You do not have to fight if the other side believes that attacking (or defecting, or entering) will...

Discipline

Discipline is the capacity to act in line with your goals and standards despite temptation, fatigue, or short-term preference. It is not punishment; it is the structure that makes...

Empty Fort Strategy

Zhuge Liang

Empty fort strategy is appearing strong when you are weak: leaving the gates open, the walls undefended, and inviting the enemy to conclude that the position is a trap. The tactic...

Exit Strategy

Exit strategy is the plan for how you stop: how you withdraw from a position, a commitment, or a conflict without being destroyed in the process. In military usage it is the route...

Guerilla Warfare

Mao / Giap

Guerilla warfare is the strategy of the weaker side: avoid pitched battle, strike where the strong cannot concentrate, and turn time and terrain into advantages. The strong want a...

Intelligence

Intelligence is the collection, analysis, and use of information to understand an opponent, environment, or situation before acting. In military and strategic contexts, it...

Lead Domino

The lead domino is the one piece that, when tipped, knocks over the rest. In strategy it is the single action or condition that makes subsequent outcomes possible or inevitable....

Potemkin Village

Grigory Potemkin

A Potemkin village is a façade: something built or staged to look impressive while hiding the lack of substance behind it. The term comes from the story that Grigory Potemkin...

Proxy War

A proxy war is a conflict in which two or more major powers compete through surrogates rather than fighting each other directly. Each power backs a side — with money, arms,...

Shock & Awe

Shock and awe is the strategy of achieving rapid dominance by overwhelming the opponent with speed, scale, and psychological impact. The goal is to paralyse the enemy's will or...

Swarming

Swarming is coordinated action by many dispersed units that converge on a target or objective without centralised command. No single node directs the whole; the units share a...

Turning Movement

A turning movement is an attack that avoids the opponent's strength by going around it — not necessarily to hit the flank, but to threaten something the opponent must protect...

Two-Front War

A two-front war is fighting two separate opponents or commitments at once — and losing the advantage of concentration. The strong position is to face one threat at a time; the...

Win Without Fighting

Sun Tzu

To win without fighting is to achieve your objective by making the opponent concede, withdraw, or align without a direct clash. Sun Tzu called it the acme of skill: "The supreme...

Winning Hearts & Minds

Winning hearts and minds is the strategy of securing lasting support from a population or group by addressing their needs, beliefs, and loyalties — not only by force or material...

Activation Energy

Reactions do not start the instant ingredients touch. They need a minimum energy input — activation energy — to overcome the barrier between initial and final state. In chemistry,...

Autocatalysis

In an autocatalytic reaction, the product of the reaction speeds up the reaction itself. The output is a catalyst for its own production. Growth is not linear; it accelerates....

Bullwhip Effect

Small changes in demand at the consumer end of a supply chain amplify as they move upstream. Retailers see a 5% bump and order 10% more to be safe. Wholesalers see lumpy orders...

Butterfly Effect

Edward Lorenz

A small change in initial conditions can produce a large change in outcome. The metaphor — a butterfly flapping its wings in Brazil could theoretically alter the path of a tornado...

Catalysis

A catalyst speeds a reaction without being consumed. It lowers the activation energy — the barrier between initial and final state — by providing an alternative path. The reaction...

Center of Gravity

Carl von Clausewitz

In physics, the center of gravity is the point at which an object's mass can be considered concentrated for the purpose of analyzing forces and balance. In military strategy,...

Chain Reaction

A chain reaction is a sequence in which each step triggers the next. One event causes another, which causes another; the reaction propagates. In nuclear physics, a neutron hits a...

Chaos Theory

Chaos theory studies deterministic systems that are nonetheless unpredictable in practice. The equations have no random terms — the future is fully determined by the present — but...

Competition

Competition is the struggle for limited resources. In ecology, species compete for food, space, and mates; the fittest persist, the rest are displaced or eliminated. The same...

Cooperation (Symbiosis)

In biology, symbiosis is the living together of different species in a way that affects one or both. Mutualism is the case where both benefit — the classic example is the bee and...

Dunbar's Number

Robin Dunbar

Human brains can maintain only so many stable social relationships. Robin Dunbar proposed a ceiling: roughly 150 people. Beyond that, you know names and faces but cannot track who...

Ecosystems

An ecosystem is a set of actors that depend on one another for survival and growth. In nature, species occupy niches; they compete, cooperate, and co-evolve. In business,...

Equilibrium

Equilibrium is the state where opposing forces balance and the system has no tendency to change unless disturbed. In physics, a ball at the bottom of a bowl is in equilibrium;...

Exaptation

Stephen Jay Gould / Elisabeth Vrba

Exaptation is the use of a trait or technology for a function other than the one it evolved or was designed for. Feathers may have evolved for thermoregulation before they were...

Filling a Vacuum

Nature abhors a vacuum; so do markets and organisations. Where there is unmet demand, unserved need, or empty authority, something will fill it. The model is physical: a vacuum...

Frame of Reference

Measurements and judgments depend on where you stand. In physics, velocity and position are relative to a frame of reference — a coordinate system or observer. There is no...

Friction & Viscosity

Friction resists motion; viscosity is resistance to flow. In physics, friction opposes relative motion between surfaces; viscosity is the internal resistance of a fluid to...

Half-life

Half-life is the time for half of something to decay or disappear. In physics, it describes radioactive isotopes: after one half-life, half the atoms have decayed; after two, a...

Hedonic Treadmill

Brickman / Campbell

People adapt to their circumstances. A raise or a new car boosts happiness for a while, then baseline returns. Setbacks hurt, then we adapt. The hedonic treadmill is the idea that...

Heisenberg Uncertainty Principle

Heisenberg

You cannot know both the position and the momentum of a particle with arbitrary precision. The more precisely you fix one, the more uncertain the other becomes. Heisenberg's...

Hierarchical Organisation

Complex systems achieve coordination through layered structure: authority, information, and tasks flow along clear reporting lines. Hierarchy is not bureaucracy — it is the...

Homeostasis

Claude Bernard / Walter Cannon

Systems that persist do so by staying within viable bounds. Homeostasis is the set of mechanisms that detect deviation from a set point and correct back toward it. Body...

Irreversibility

Jeff Bezos

Some changes cannot be undone. Irreversibility is the property that certain processes run one way: time, entropy, and many decisions move forward only. You can't unburn fuel,...

Niches

A niche is a subset of the environment where specific conditions allow a subset of players to survive and thrive. In ecology, a niche is the role a species plays — what it eats,...

Reciprocity (Physics)

For every action there is an equal and opposite reaction. Newton's third law is reciprocity in mechanics: forces come in pairs. When you push on a wall, the wall pushes back. When...

Relativity

Einstein

Outcomes and judgments depend on the frame from which they're observed. Relativity in physics — Einstein's special and general relativity — says that measurements of time, length,...

Scale & Limits

Things that work at one size often break or bend at another. Scale and limits is the principle that systems have operating ranges: too small and you don't get the benefits of...

Signalling & Countersignalling

Signalling is the use of observable actions or traits to convey information that would otherwise be hard to verify. Because the signal is costly or hard to fake, it is credible. A...

Tendency to Minimize Energy Output

Systems — physical, biological, and organisational — tend toward states that require less energy to maintain. A ball rolls downhill. Organisms conserve calories. People take...

Velocity

Velocity is rate of change with direction — how fast you're moving and where. In physics it's displacement per unit time (vector); in product and orgs it's output per unit time in...

Burden of Proof

Who must prove what? Burden of proof answers that question. The party making a claim bears the obligation to support it with evidence. The party defending the status quo or...

Cargo Cults

Richard Feynman

Copying the surface without the substance produces ritual, not results. Cargo cults take their name from Pacific islanders who, after Allied forces left post–WWII, built bamboo...

Cave of Plato

Plato

What we take for reality can be shadows on a wall. In Plato's Republic, prisoners are chained in a cave, facing a wall. They see only shadows cast by a fire behind them — shadows...

Chilling Effect

A chilling effect occurs when the threat of legal action, retaliation, or sanction causes people to avoid lawful conduct. The harm is not the penalty itself but the...

Consequentialism

The right action is the one that produces the best outcome. Consequentialism judges acts (or rules, or character) by their consequences — not by intent, duty, or intrinsic...

Due Process

How a decision is made can matter as much as what is decided. Due process is the requirement that decisions affecting rights or interests be made through fair procedures: notice,...

Effective Altruism

Do the most good you can with what you have. Effective altruism (EA) applies evidence and reason to the question of how to help others: compare interventions by impact (lives...

Ethos Pathos Logos

Aristotle

Persuasion runs on three rails: who you are, what they feel, and what you can prove. Aristotle distinguished ethos (character, credibility), pathos (emotion), and logos (reason,...

Golden Rule

The Golden Rule — treat others as you would have them treat you — is a reciprocity norm found across traditions: Judaism (Hillel), Christianity (Jesus), Islam (Hadith),...

Good Faith

Deal honestly; don't exploit the letter while violating the spirit. Good faith is the obligation to act with honesty, fairness, and fidelity to the purpose of an agreement or...

Historic Recurrence

History doesn't repeat, but it rhymes. Historic recurrence is the observation that similar patterns — boom and bust, rise and fall of empires, technological disruption, political...

Importance of Geography

Place shapes outcome. Geography — location, terrain, climate, resources, neighbours — constrains and enables. It's not destiny; it's a set of conditions that make some paths...

Inclusive Economic & Political Institutions

Daron Acemoglu / James Robinson

Inclusive institutions spread power and opportunity. They enforce property rights for a broad cross-section of society, allow free entry into markets and politics, and constrain...

Nuclear Option

The nuclear option is an action so costly or destructive that it is rarely used — but the threat of it shapes behaviour. The term comes from literal nuclear weapons: their use...

Precedents

A precedent is a past decision or outcome that is used to guide or justify a current one. In law, precedents (case law) bind or persuade future courts: what was decided before...

Regulatory Capture

George Stigler

Regulatory capture occurs when a regulator comes to serve the interests of the industry it oversees rather than the public. The regulator may have been captured at birth (designed...

Secrets

Peter Thiel

A secret, in Peter Thiel's formulation, is something important that is true but not widely believed. It is not a fact everyone knows, and not a belief that is false — it is a...

Ship of Theseus

The Ship of Theseus is a thought experiment: if you replace every plank of a ship, one by one, is it still the same ship? If you take the old planks and reassemble them into a...

Shirky Principle

Clay Shirky

The Shirky Principle, named after Clay Shirky: "Institutions will try to preserve the problem to which they are the solution." A drug-rehab centre has an incentive to have clients...

The Overton Window

Joseph Overton

The Overton window is the range of ideas that are acceptable to discuss in public at a given time. Named after Joseph Overton of the Mackinac Center, the concept describes how...

The Trolley Experiment

Philippa Foot / Judith Jarvis Thomson

The trolley problem is a thought experiment: a runaway trolley will kill five people unless you pull a lever, diverting it onto another track where it will kill one. Do you pull...

Utilitarianism

Jeremy Bentham / John Stuart Mill

Utilitarianism is the view that the right action is the one that produces the greatest total well-being (utility) for the greatest number. Jeremy Bentham and John Stuart Mill gave...

Veil of Ignorance

John Rawls

The veil of ignorance is a thought experiment from John Rawls: when designing the rules of society (or any collective), imagine you don't know which position you'll occupy. You...

Attention Residue

Sophie Leroy / Cal Newport

In 2009, Sophie Leroy at the University of Minnesota published a paper that should have restructured every calendar in every knowledge-work organisation on the planet. The...

Availability Cascade

Timur Kuran / Cass Sunstein

In 1999, Timur Kuran and Cass Sunstein published a paper that explains half of what goes wrong in public discourse: "Availability Cascades and Risk Regulation." The concept is a...

Backfire Effect

Brendan Nyhan / Jason Reifler

In 2010, Brendan Nyhan and Jason Reifler published a study that broke a fundamental assumption about how persuasion works. They showed groups of participants fake news articles...

Big Five Personality Traits

Paul Costa / Robert McCrae

In 1992, Paul Costa and Robert McCrae published the NEO Personality Inventory — Revised, and personality psychology finally had a framework that survived replication. After...

Bounded Rationality

Herbert Simon

Herbert Simon introduced bounded rationality in 1955 and won the Nobel Prize in Economics for it in 1978. The core claim dismantled a century of economic orthodoxy: humans do not...

Chesterton's Fence

G.K. Chesterton

G.K. Chesterton: "Don't ever take a fence down until you know the reason it was put up." Before removing a rule, process, or structure, understand why it exists. The principle is...

Classical Conditioning

Pavlov

Pavlov (1890s): a neutral stimulus paired with an unconditioned stimulus becomes a conditioned stimulus. The bell → salivation. The mechanism is deceptively simple: pair a neutral...

Commitment & Consistency

Robert Cialdini

Cialdini's principle: people want to be consistent with their past commitments. Foot-in-the-door — a small yes leads to a bigger yes. Public commitments are stickier than private...

Conformity

Solomon Asch / Gregory Berns

In 1951, Solomon Asch put seven people in a room and showed them a line on a card. He then showed them three comparison lines — A, B, and C — and asked which one matched the...

DISC Model

William Marston / Walter Clarke / John Geier

In 1928, William Marston published Emotions of Normal People, proposing four behavioural styles: Dominance (direct, results-driven), Influence (outgoing, relationship-focused),...

Delayed Gratification

Walter Mischel

In 1970, Walter Mischel sat four-year-olds down at a table at Stanford's Bing Nursery School and placed a single marshmallow in front of each one. The deal was simple: eat the...

Denial

Elizabeth Kübler-Ross

In 1975, a 24-year-old Kodak engineer named Steven Sasson built the first digital camera. It was ugly — a toaster-sized device that captured a 0.01-megapixel black-and-white image...

Ego Depletion

Roy Baumeister / Shai Danziger

In 1998, Roy Baumeister ran an experiment that reshaped how psychologists think about self-control. Subjects were placed in a room with freshly baked chocolate chip cookies and a...

Embodied Cognition

Lakoff & Johnson

Lakoff and Johnson's framework: thought is shaped by the body. We "grasp" ideas, "warm" to people, give "cold" shoulders. The language is not decorative. It reveals the...

Essentialism

Greg McKeown / Dieter Rams

In 2014, Greg McKeown published Essentialism: The Disciplined Pursuit of Less — a book whose subtitle contains its entire thesis. Not "the lazy pursuit of less." Not "the...

Gambler's Fallacy

On August 18, 1913, at the Monte Carlo Casino, the roulette wheel landed on black. Then black again. And again. Twenty-six consecutive times. Gamblers watched the first ten spins...

Golem Effect

Robert Rosenthal / Lenore Jacobson

In 1968, Robert Rosenthal and Lenore Jacobson ran an experiment at a San Francisco elementary school that would reshape how psychologists thought about expectation and...

Hippo Problem

Avinash Kaushik

Highest Paid Person's Opinion: the tendency to defer to the most senior person in the room, regardless of data. Avinash Kaushik named it in 2006 while watching web analytics teams...

Hyperbolic Discounting

Richard Herrnstein / George Ainslie

We discount future rewards more than exponential discounting predicts. $100 today vs $110 tomorrow — we take $100. $100 in a year vs $110 in a year and a day — we take $110. The...

Illusion of Control

Ellen Langer

In 1975, Ellen Langer ran a deceptively simple experiment at Yale. She sold lottery tickets to office workers. Half chose their own ticket. Half were assigned one at random....

Illusory Truth Effect

Lynn Hasher / David Goldstein / Thomas Toppino

In 1977, Lynn Hasher, David Goldstein, and Thomas Toppino ran an experiment that should have rewritten every communications playbook. They presented subjects with plausible...

Intrinsic vs Extrinsic Motivation

Edward Deci / Richard Ryan

Edward Deci and Richard Ryan's Self-Determination Theory identifies three innate psychological needs that drive human motivation: autonomy (the need to direct your own life and...

Intuition

Kahneman / Klein / Jobs

Daniel Kahneman's System 1 is fast, automatic, pattern-based. It does not deliberate. It recognises. Intuition is compressed experience — the brain's way of delivering answers...

Irrational Escalation

Barry Staw

Sunk cost fallacy in action: doubling down on failing projects to justify past investment. Barry Staw's 1976 study gave MBA students the role of a financial VP allocating R&D...

Learned Helplessness

Martin Seligman / Steven Maier

In 1967, Martin Seligman and Steven Maier ran an experiment at the University of Pennsylvania that would rewrite the psychology of motivation. They placed dogs in a shuttle box —...

Maslow's Hierarchy

Abraham Maslow

Abraham Maslow published "A Theory of Human Motivation" in 1943 and proposed five levels of need: physiological, safety, love/belonging, esteem, self-actualization. Lower needs...

Mental Accounting

Richard Thaler

Richard Thaler (1985): people treat money differently based on where it came from or what it's for. Lottery winnings are "house money" — spent more freely. Tax refunds feel like...

Motivation

Victor Vroom

Motivation is the force that drives behaviour. Victor Vroom's Expectancy Theory (1964) distils it into three multiplicative factors: expectancy × instrumentality × valence. Can I...

Neglect of Probability

Kahneman & Tversky / Gerd Gigerenzer

Humans don't evaluate risk by computing probabilities. They evaluate risk by imagining outcomes. The more vivid the outcome — the more easily they can picture the plane crash, the...

Nudging

Thaler & Sunstein

Thaler and Sunstein (2008): small changes in choice architecture that alter behaviour without restricting options. Organ donation opt-out vs opt-in — participation swings from...

Overthinking

Barry Schwartz / Sheena Iyengar / Jeff Bezos / Reed Hastings

Analysis paralysis is excessive rumination that impairs decision-making. The brain keeps cycling through options, scenarios, and objections long after the marginal value of...

Pattern Matching

Humans are pattern-seeking machines. We see faces in clouds, conspiracies in randomness. The brain compresses overwhelming input into actionable understanding by matching new...

Placebo Effect

Expectation creates physiological change. Sugar pills reduce pain when patients believe they're medicine — not because the pain is imagined, but because the brain releases...

Priming

John Bargh

Exposure to a stimulus influences response to a subsequent stimulus. Bargh's elderly-walking study (1997): subjects primed with "elderly" words — Florida, bingo, wrinkle, grey —...

Reactive Devaluation

Lee Ross

Lee Ross (1995): proposals are devalued because of who proposed them. The same deal from an adversary is worth less than from a neutral party. In mergers, the target's proposal is...

Risk Compensation

Sam Peltzman

In 1975, University of Chicago economist Sam Peltzman published a study that infuriated the safety establishment. He looked at the effect of mandatory seatbelt laws on traffic...

Scout Mindset

Julia Galef

Julia Galef spent a decade studying why some people update their beliefs when confronted with evidence and others dig in. Her framework, published in The Scout Mindset (2021),...

Selective Perception

Christopher Chabris / Daniel Simons

We perceive what we expect or want to see. The same data supports opposing conclusions. Confirmation bias is selective perception in action — the downstream effect of a filter...

Sensemaking

Karl Weick / Wagner Dodge

Karl Weick: how people make sense of ambiguous situations. Sensemaking is retrospective — we understand what we did after we've done it. It's social — we construct meaning through...

Seven Deadly Sins

Pope Gregory the Great

Pride, greed, wrath, envy, sloth, gluttony, lust — Pope Gregory the Great codified these seven failure modes in 590 AD. Strip the theology and what remains is a taxonomy of...

Stereotyping

Kahneman / Bertrand / Mullainathan

Applying generalized beliefs about a group to individuals. The brain's compression algorithm — efficient but often wrong. In hiring: "Stanford grads are smart" functions as a...

Suggestibility

Loftus

The tendency to accept and act on suggestions from others. Children are highly suggestible; adults less so, but not immune. Leading questions shape memory — Loftus showed that a...

Tribalism

Tajfel

In-group favouritism and out-group hostility. We evolved in tribes; us vs them is default. The brain doesn't need a reason to form a tribe. It needs a label. Tajfel proved this...

Variable Reinforcement

B.F. Skinner / Wolfram Schultz

B.F. Skinner put pigeons in boxes and gave them food pellets for pressing a lever. When the pellet came every time — fixed reinforcement — the pigeons pressed at a steady rate....

Zeigarnik Effect

Bluma Zeigarnik

In 1927, Bluma Zeigarnik was sitting in a Viennese café with her doctoral adviser, Kurt Lewin, when Lewin noticed something about the waiter. The waiter could remember every...

Automation

Automation is the use of technology to perform tasks with minimal human intervention. The goal is to increase throughput, reduce cost, and remove variability — but automation...

Backup System Model

A backup system is a parallel capability that takes over when the primary fails. The model is simple: identify single points of failure, then add fallbacks that activate...

Breakpoints

A breakpoint is a value or condition at which system behaviour changes discontinuously. Below the breakpoint, one rule holds; above it, another. The concept comes from programming...

Causal Loops Diagrams

Forrester / Senge

Causal loop diagrams (CLDs) map how variables influence each other over time. Each arrow is a causal link: A → B means "A affects B." The sign on the arrow indicates direction:...

Churn

Churn is the rate at which customers, users, or subscribers leave. It is the outflow in a stock-and-flow system: the customer base is the stock; acquisition is the inflow; churn...

Counterparty Risk

Counterparty risk is the risk that the other party to a contract, trade, or dependency will not fulfil their obligation. They might default, delay, or renege. You perform; they...

Fail-safes

A fail-safe is a mechanism that defaults to a safe state when something goes wrong. Failure of a component triggers a response that limits damage rather than amplifying it. Dead...

Friction

Friction is resistance to motion or change. In physics it opposes movement; in systems it opposes flow — of users, decisions, money, or information. Friction slows things down and...

Hysteresis

Hysteresis is when the state of a system depends not only on current conditions but on its history. The path you took to get here matters. The same input can produce different...

Interdependence

Interdependence means that parts of a system depend on each other. Change in one part affects others; those effects can feed back. The system is a web of relationships, not a set...

Irreducibility

Irreducibility means the whole cannot be fully explained or predicted from the parts alone. The system has properties or behaviours that emerge from interaction and don't exist at...

Le Chatelier's Principle

Le Chatelier's principle says: when a system at equilibrium is disturbed by a change in condition (temperature, pressure, concentration), the system shifts in the direction that...

Normal Accidents

Charles Perrow

Normal accident theory, from Charles Perrow, says that in systems that are both complex (many parts interacting in non-obvious ways) and tightly coupled (little slack, fast...

Optimization

Optimization is improving a system toward a defined objective — making a chosen variable as good as possible given constraints. The objective might be cost, speed, throughput, or...

Paradox of Automation

The paradox of automation: the more reliable and capable the automated system, the less practice humans get — and the more critical human intervention becomes when the system...

Quality Control

Quality control is the set of activities that ensure output meets a defined standard — detection, measurement, and correction of deviation. It can happen at the end (inspection)...

Redundancy

Redundancy is duplicate capacity or parallel paths so that if one element fails, the system can still function. It is a hedge against failure: you pay a cost (extra components,...

Refactoring

Refactoring is changing the internal structure of a system without changing its external behaviour — improving how it's built so that future change is easier, without (in...

Reflexivity

George Soros

Reflexivity is the two-way causal link between belief or perception and reality: beliefs change behaviour, behaviour changes outcomes, and outcomes reinforce or revise beliefs....

Slack

Tom DeMarco

Slack is spare capacity — time, resources, or optionality — that is not committed to the current plan. It absorbs shock, allows reallocation when priorities change, and reduces...

Standard Operating Procedure

A standard operating procedure (SOP) is a documented, repeatable sequence of steps for a defined task or situation. It reduces variation, captures knowledge, and makes outcomes...

Stress Testing

Stress testing is deliberately subjecting a system to extreme or adverse conditions to see how it behaves — and where it breaks. The goal is to expose failure modes before they...

The Critical Few

The critical few are the small number of factors, people, or actions that drive the majority of outcomes. Most of the effect comes from a few causes; most causes contribute...

The Experimental Mindset

The experimental mindset is the habit of treating beliefs as hypotheses and the world as testable. Instead of defending a view until it breaks, you state what would disprove it,...

10 Ways to Evaluate Market

A structured checklist of ten dimensions to assess whether a market is worth entering or scaling in: size, growth, concentration, margins, cycles, defensibility, timing,...

5 W's and 1H

Who, What, When, Where, Why, and How: six questions that force a complete brief. Applied to any initiative, product, or decision, they ensure you don't ship or commit without...

Accumulation

Outcomes compound when small, repeatable gains stack over time — users, data, reputation, capability. Accumulation is the dynamic: not one big move but many small ones that add...

Alternative Dispute Resolution

ADR (mediation, arbitration, negotiation) resolves conflict outside courts. The idea: faster, cheaper, and often better outcomes than litigation by focusing on interests and...

Alternatives

Every choice is made against alternatives — the other options you could take. Thinking in alternatives forces explicit comparison: what you give up, what you gain, and what the...

Amplification

Amplification is using existing reach or mechanisms to multiply the impact of a message, product, or action. One input yields many outputs because channels, audiences, or...

Attention

Attention is the scarce resource: people have limited focus and time. Winning it means being relevant, salient, and timely so your message or product gets noticed and remembered....

BANT

BANT is a sales qualification framework: Budget, Authority, Need, and Timeline. Before investing in a deal, confirm the prospect has money to spend, someone with power to decide,...

Baker's Dozen

Baker's dozen is the practice of giving 13 when 12 is expected — deliberate overdelivery. In business it means exceeding the stated offer: extra value, faster delivery, or a bonus...

Barriers to Purchase

Barriers to purchase are anything that blocks or slows a buyer from completing a transaction: friction (steps, forms, complexity), uncertainty (will it work? can I trust?), or...

Basketball Politics

Basketball politics is the dynamic where a few people have the ball (information, decisions, access) and others orbit around them, waiting for a pass. In organisations, it shows...

Best Content Involves Red Pill

"Best content involves red pill" means the most effective content often challenges what the audience assumes — a contrarian take, an uncomfortable truth, or a reframe that changes...

Buffer

A buffer is capacity or time held in reserve so the system can absorb variation without failing. In operations, it's extra inventory or capacity; in time, it's slack between...

Call to Action

A call to action (CTA) is the explicit instruction that tells the audience what to do next: sign up, buy, share, reply. Without it, interest rarely converts. The core idea: every...

Channel Evaluation Framework

A channel evaluation framework is a structured way to assess and compare acquisition channels: which channels can reach your customer, at what cost, and with what control....

Channel vs Product-led Growth

Channel-led growth uses sales, partnerships, or paid acquisition to get the product in front of buyers; product-led growth (PLG) uses the product itself to acquire and expand...

Compromise Effect

The compromise effect is the tendency to prefer a middle option when choices are ordered by some dimension (price, size, risk). The "middle" feels safe, reasonable, and justified...

Confirming Conversations

Confirming conversations are exchanges that validate what you already believe or want to hear — "yes, that's right," "we're on track," "customers love it." They feel good but...

Conjoined Triangles of Success

The Conjoined Triangles of Success is a satirical framework from Silicon Valley (HBO): two triangles representing "Failure" and "Success" that share a base — the joke is that the...

Contrast Is Drug

Contrast is drug: the human brain is wired to notice and remember difference — before vs after, old vs new, pain vs relief. In marketing and product, contrast creates attention...

Controversy

Controversy is disagreement or provocation that triggers strong reaction — approval or outrage — and often spreads because people can't help engaging. In building and scaling,...

Core Human Drives

Core human drives are the deep motivations that shape behavior: survival, belonging, status, meaning, growth, and the like. Different frameworks name them differently (e.g....

Cost

Cost is what you give up to get something — money, time, attention, optionality. In building and scaling, "cost" usually means more than COGS: it includes opportunity cost (what...

Critical Assumptions

Critical assumptions are the beliefs that must hold for your strategy or bet to work — "customers will pay for X," "we can acquire users at cost Y," "this channel will scale." If...

Customer Buying Journey

The customer buying journey is the path from first awareness to purchase and beyond: awareness → consideration → decision → purchase → loyalty/advocacy. Stages may be named...

Customer Hunting Types

Customer hunting types are the different ways you go to market to acquire customers: outbound (you reach out), inbound (they find you), partner/channel (someone else sells or...

Customer Personas

Customer personas are archetypal descriptions of who you're selling to — a named, concrete profile (e.g. "Marketing Mary," "IT Ian") that captures goals, pain points, context, and...

Damaging Admission

A damaging admission is when you voluntarily surface a weakness, limitation, or failure that the other side could use against you. Counterintuitively, doing so often increases...

Demonstration

Demonstration is showing the product or outcome in action so the prospect sees the result rather than just hearing a claim. It reduces perceived risk and disbelief: people believe...

Desire

Desire is the want that precedes action — the pull toward an outcome, identity, or experience. In business, you don’t create desire from nothing; you connect your offer to desires...

Distribution Channel

A distribution channel is the path through which your product or message reaches the customer — direct sales, partners, marketplaces, content, paid acquisition, or product-led...

Double Down on Strengths

Double down on strengths means investing more in what already works and where you’re already strong, instead of spreading effort across weaknesses or new bets. It’s the strategic...

Duplication

Duplication is scaling by replicating a working unit — the same process, format, or model — in new contexts. Instead of inventing something new each time, you copy what works:...

Economic Values

Economic values are the forms of value a business can create and capture — not just product for money, but convenience, certainty, status, access, or experience in exchange for...

Education-Based Selling

Education-based selling is leading with useful information and insight so the prospect learns something before you ask for a commitment. You’re not pushing a product first; you’re...

End Result

End result is the outcome you’re building toward — the customer state, the metric, the moment that defines success. Thinking from the end result means starting with that outcome...

Exclusivity

Exclusivity is the perception that an offer, access, or identity is limited — by invitation, capacity, qualification, or time. It increases perceived value and desire: people want...

Expectation Effect

The expectation effect is the tendency for expectations — what we believe will happen — to influence what actually happens. High expectations can improve performance (Pygmalion);...

Force Multiplier

A force multiplier is a factor that amplifies the output of a given input — tools, people, process, or structure that make one unit of effort produce more than one unit of result....

Four Pricing Methods

Four pricing methods frame how you set price: cost-plus (markup on cost), competitive (match or beat alternatives), value-based (tied to outcome or value delivered), and...

Get Shit Done

Get shit done (GSD) is the bias toward execution over planning: ship, learn, and fix rather than perfect before moving. The core idea: output beats intention. Done is better than...

Go-For-It Window

The go-for-it window is the period when conditions align to make a bold move — market, team, capital, or opportunity — and when delay means the window closes. The core idea:...

Hassle Premium

The hassle premium is the extra willingness to pay when you remove friction, complexity, or effort from the customer — the “I’ll pay more so I don’t have to deal with it” effect....

Incremental Augmentation

Incremental augmentation is improving a product, process, or system in small, additive steps rather than big rewrites. Each step builds on the last; you augment what exists...

Institutional Knowledge

Institutional knowledge is the collective know-how that lives in people, practices, and context — how things really work, why decisions were made, and who to ask. The core idea:...

Intermediation & Disintermediation

Intermediation is the insertion of a middle layer between producer and consumer (e.g. distributor, marketplace, aggregator); disintermediation is removing that layer so buyer and...

Levels of Awareness

Levels of awareness describe where the prospect is in relation to their problem and your solution: unaware, problem-aware, solution-aware, product-aware, or most-aware. The core...

Loyalists vs Mercenaries

Loyalists are people (customers, employees, partners) who stay for mission, relationship, or identity; mercenaries are in it for the best deal or opportunity and will leave when a...

Major Acquisition Lanes

Major acquisition lanes are the primary channels or motions that bring customers in — paid, organic, referral, sales, partnerships, product-led. The core idea: growth comes from a...

Managing to Person

Andy Grove

Every report is different — in skill, motivation, and context. Managing to the person means adjusting style, cadence, and expectations to where each individual actually is, not...

Mercenary Rule

The mercenary rule: if you pay people only for output and give them no stake in the outcome, they behave like mercenaries — they optimise for the payment, not the mission. When...

Most Underrated Marketing Channel

The most underrated marketing channel is the one your competitors ignore or undervalue — not the flashiest or newest platform. Often it's word of mouth, direct outreach, content,...

Most Value Created After V1

The first version ships the idea; the real value is built in every iteration that follows. V1 proves the concept works; V1.1 through V100 prove the team can learn and compound....

Multiplication

Multiplication is creating value that scales with more of the same input — each unit of effort or asset produces more than its cost, so total output grows faster than total input....

Next Best Alternative

The next best alternative is what the other party would do if they didn’t choose you — their best option aside from the deal on the table. In negotiation, sales, and positioning,...

Option Fatigue

Option fatigue is the paralysis that sets in when a customer or decision-maker faces too many choices. More options don't mean more sales — past a threshold, they mean fewer. The...

Paradox of Specificity

The paradox of specificity: the more narrowly you define who you’re for and what you do, the more strongly you attract that segment and the easier it is to spread beyond it....

Permission

Permission is the right to ask for attention, time, or action — granted when you’ve earned trust or delivered value first. In marketing and sales, you don’t get to pitch until you...

Persuasion Resistance

Persuasion resistance is the pushback people feel when they sense they’re being sold or manipulated — they dig in, reject the message, or do the opposite. The harder and more...

Predictability

Predictability is the degree to which outcomes, behaviour, or process can be relied on — same inputs yield same (or acceptably similar) results. In building and scaling,...

Preoccupation

Preoccupation is the state of being mentally occupied by something else — so that attention and capacity for the task at hand are reduced. In building and scaling, preoccupation...

Price Transition Shock

Price transition shock is the negative reaction — surprise, resistance, churn — when a customer faces a new or higher price after being anchored to an old one. Free to paid,...

Pricing Uncertainty Principle

The pricing uncertainty principle: you cannot fully know both the true value to the customer and the optimal price at once. Changing price changes revealed demand; measuring...

Probable Purchaser

A probable purchaser is the person most likely to buy — not everyone who could, but the narrow segment who will. The concept forces founders to stop marketing to the general...

Prototype

A prototype is a rough, early version built to test an idea before committing full resources. It doesn't need to work perfectly — it needs to answer a question: does this concept...

Psych Framework Customer Buying Journey

The Psych Framework maps the customer buying journey through psychological stages — not just funnel steps. At each stage, a different psychological need dominates: awareness...

Qualification

Qualification is the process of checking whether a prospect has need, authority, budget, and timeline to buy — so you invest in those who can close and don't waste time on those...

Quality

Quality is fitness for purpose taken to its extreme — the standard where every detail serves the user and nothing is left sloppy. It's not gold-plating; it's the discipline of...

Quality Signals

Quality signals are the visible cues that communicate a product or brand's standard before the buyer can fully evaluate it. Materials, packaging, design, price, endorsements,...

Reactivation

Reactivation is winning back users or customers who have gone dormant — stopped using, stopped buying, or lapsed. They already know you; the cost to re-engage is often lower than...

Receptivity

Receptivity is how open a person is to your message or offer at a given moment — attention, readiness, and willingness to engage. The same message lands differently depending on...

Relative Importance Testing

Relative importance testing measures how much each factor (feature, attribute, message) drives choice or satisfaction when considered together — not in isolation. People say one...

Reputation

Reputation is what others believe about you based on past behaviour — a summary of trust built or broken over time. It's hard to build and easy to lose. The core idea: reputation...

Risk Reversal

Risk reversal is shifting risk from the buyer to the seller — guarantees, free trials, money-back offers, or "we only win if you win" structures. The buyer's main objection is...

Social Status

Social status is one's relative position in a hierarchy that others care about. People seek to gain or defend status; products and experiences often function as status signals....

Sphere of Influence

Sphere of influence is the set of people, decisions, and outcomes you can actually affect. It's bounded by authority, relationships, and reach. The core idea: focus effort inside...

Strategic vs Financial Acquisition

Acquirers buy companies for two broad reasons: strategic (capability, market, synergy) or financial (cash flow, multiple arbitrage, cost cuts). Strategic acquisitions aim to...

Surfing

Surfing is the metaphor for riding a wave of change — technology, regulation, or demand — rather than fighting it. You don't create the wave; you spot it early, position, and...

Systemization

Systemization is turning one-off or ad hoc work into repeatable processes, checklists, and standards so the outcome doesn't depend on a single person or moment. The core idea:...

Technology Adoption Lifecycle

Geoffrey A. Moore

The technology adoption lifecycle segments customers by when and why they adopt something new: innovators, early adopters, early majority, late majority, laggards. Each segment...

Three Universal Currencies

Beyond money, people and organisations trade in time and attention. Time is finite and irreplaceable; attention is the scarce resource that gates focus and decisions. The core...

Throughput

Throughput is the rate at which a system produces its desired output — units shipped, deals closed, features deployed, customers onboarded. It measures the flow of value, not the...

Transaction

A transaction is a discrete exchange — something of value moves from one party to another in return for something else (money, commitment, service). The core idea: every deal,...

Triage

Triage is sorting items (tasks, opportunities, customers) by urgency and impact so you allocate limited resources to what matters most. It comes from emergency medicine: not...

Value-Based Selling

Value-based selling prices and pitches based on the value the buyer receives, not the cost to deliver. A tool that saves the customer $500K/year is worth far more than its $50K...

Version Two is Lie

"Version Two" is a lie because it rarely arrives as promised. When teams say "we'll fix it in V2," they're using a future release as an escape valve for present-day trade-offs —...

Weekly 1-1s

Weekly one-on-ones are a cadence: a fixed, recurring slot for each report to talk with their manager. The purpose is alignment, unblocking, and feedback — not status theatre. When...

Weird > Average

Distinctiveness beats bland competence. "Weird" here means recognisably different — a clear point of view, a narrow wedge, or a choice that some love and some hate. Average is the...

Zero Tolerance

Zero tolerance means no exceptions for certain behaviours or standards: one violation is one too many. It applies where the cost of a single failure is existential (safety,...

Average Rule

When multiple independent estimates or signals bear on the same quantity, combining them (e.g. by averaging) often beats relying on one. The average rule is a decision heuristic:...

Belady's Algorithm

Belady

Belady's algorithm (MIN or OPT) is the optimal offline page-replacement policy for a cache: evict the page that will be used farthest in the future. It minimizes cache misses when...

Binary Search

Binary search finds a target in a sorted sequence by repeatedly halving the search space: compare to the middle element, then search only the half that can contain the answer....

Godwin's Law

Mike Godwin

Godwin's Law: "As an online discussion grows longer, the probability of a comparison involving Nazis or Hitler approaches 1." It's a meta-observation about discourse decay —...

Interrupt Coalescing

Interrupt coalescing batches multiple interrupt triggers into a single handling event. Instead of the CPU switching context on every interrupt, the system waits briefly or until a...

Lagrangian Relaxation

Lagrangian relaxation turns a hard constrained problem into a sequence of easier ones: move constraints into the objective with penalty multipliers (Lagrange multipliers), then...

Laplace's Law

Pierre-Simon Laplace

Laplace's rule (or rule of succession) estimates the probability of an event that has occurred k times in n trials as (k + 1) / (n + 2). It's a simple Bayesian prior: start from...

Least Recently Used

LRU (Least Recently Used) is a cache eviction policy: when the cache is full, evict the item that was used longest ago. It assumes temporal locality—recently used items are more...

Multiplicative Rule

The multiplicative rule says that for independent events, the probability of all occurring is the product of their individual probabilities. If each step in a chain has 90%...

Optimization Algorithms

Optimization algorithms search for the best solution in a space of possibilities: maximise reward or minimise cost. Greedy methods (e.g. hill climbing) move toward better...

Packet Switching

Packet switching sends data in small, discrete packets that can be routed independently across a shared network. Unlike circuit switching (dedicated path for the whole session),...

Scheduling & Prioritization

Scheduling and prioritisation algorithms determine the order in which tasks are processed when resources are limited. Key heuristics: Earliest Due Date (EDD) minimises maximum...

Sorting Algorithms

Sorting puts a sequence in order (e.g. by value or key). Different algorithms trade off time, space, and stability. Comparison-based sorts (e.g. merge sort, quicksort) use only...

Statistical Learning

Statistical learning is the framework for learning from data: choose a model class, define loss, and fit by minimising empirical risk (e.g. squared error, cross-entropy). Core...

The Copernican Principle

The Copernican principle says: don't assume a privileged position. We're not at a special time or place in the universe—or in a distribution. Applied to duration: if you have no...

The Gittens Index

John Gittins

The Gittins index assigns a single number to each arm in a multi-armed bandit problem (with geometric discounting): it's the value of playing that arm optimally versus a fixed...

Threshold Rule

A threshold rule is a decision rule that triggers an action when a quantity crosses a level: "if x ≥ T, do A; else do B." It turns a continuous or noisy signal into a discrete...

Upper Confidence Bound

UCB (Upper Confidence Bound) is a simple policy for the multi-armed bandit: for each arm, compute an index = estimated mean + confidence bound (e.g. proportional to √(log n /...

Zawinski's Law

Jamie Zawinski

Zawinski's law (Jamie Zawinski, Netscape/Mozilla): "Every program attempts to expand until it can read mail. Those programs which cannot so expand are replaced by ones that can."...

Abdication of Responsibility

Abdication of responsibility occurs when a party with decision rights or obligations shifts blame, cost, or accountability onto others while retaining the upside. In economics and...

Bribery

Bribery is the use of payment or favours to distort a decision in the payer's favour. In economics it appears as a transfer that bypasses normal price or merit: the briber pays...

Cancer Surgery Formula

The cancer surgery formula is a decision heuristic: cut out the bad with clean margins and do not try to save the tumour. In business and strategy it means exiting losing...

Cap-and-trade Systems

Cap-and-trade is a market-based policy that sets a total limit (cap) on emissions or use of a resource and issues tradeable permits so that the right to emit or use can be bought...

Controlling the Center

Controlling the center is a strategic idea from chess and game theory: the player who dominates the central squares gains flexibility, threat range, and options. In markets and...

Cooperative/Non-cooperative

In game theory, games are cooperative when players can make binding agreements and share payoffs; they are non-cooperative when each player acts independently and no enforceable...

Costs: Sunk/Transaction/Switching/Search

Four cost types shape decisions and markets. Sunk costs are already spent and irrecoverable — they shouldn't influence future decisions but almost always do. Transaction costs are...

Factors of Production

Output requires inputs: in economics these are labour, capital, land, and often entrepreneurship. Labour is human effort; capital is produced goods used to produce more (machines,...

GDP

GDP (gross domestic product) is the total value of final goods and services produced in an economy over a period — usually a year or a quarter. It can be measured as output (value...

Game Theory: Combinatorial

Combinatorial game theory studies games with a finite set of positions, perfect information, and no chance — e.g. chess, go, nim. The key idea: under certain conditions, the game...

Game Theory: Discrete & Continuous

In discrete games, players choose from a finite set of actions (e.g. cooperate or defect, enter or stay out). In continuous games, they choose from a continuum (e.g. price,...

Game Theory: Evolutionary

Evolutionary game theory studies how strategies spread in a population when payoffs determine reproductive or imitation success. There are no rational, calculating players — only...

Game Theory: Infinitely Long

When a game is repeated indefinitely (no known last period), the set of equilibria expands. In the one-shot prisoner's dilemma, defection dominates. In an infinitely repeated...

Game Theory: Mean Field

Mean-field game theory studies settings with very many players where each player's payoff depends on their own action and on the aggregate distribution of others' actions — not on...

Game Theory: Metagames

A metagame is a game about which game to play — or how to change the rules, the players, or the payoffs. Instead of taking the game as given and choosing a strategy, you ask: can...

Game Theory: Perfect & Imperfect Information

John von Neumann / Oskar Morgenstern

In perfect-information games, every player knows the full history and current state when they move; in imperfect-information games, some moves or types are hidden. Chess is...

Game Theory: Pooling Games

In signalling games, different "types" (e.g. high vs low quality) can send the same signal — a pooling equilibrium — or separate — a separating equilibrium. Pooling means the...

Game Theory: Stochastic Outcomes

In many games, the link between strategy and outcome is probabilistic: you choose an action, but the result depends on chance (nature’s move) or mixed strategies. Analysing such...

Inflation

Inflation is a sustained rise in the general level of prices — the value of money in terms of goods falls. It's usually measured by a price index (e.g. CPI, PCE) over a period....

Iron Law of Civilization

The "iron law" (in some formulations) is that civilisation advances when the returns to productive behaviour exceed the returns to predation or extraction — and decays when the...

NIMBY

NIMBY — "Not In My Back Yard" — is the pattern where people support a policy or project in the abstract but oppose it when it affects their own locale. Benefits are diffuse or...

One Variable

"One variable" thinking is the discipline of changing or analysing one factor at a time while holding others constant — the experimental and mental equivalent of ceteris paribus....

Product Lifecycle

The product lifecycle is the sequence from introduction through growth, maturity, and decline. Demand and competition shift across stages: early, few competitors and often high...

Purchasing Power Parity

Purchasing power parity (PPP) is the idea that, in the long run, exchange rates should move so that a given basket of goods costs the same across countries when expressed in one...

Seizing the Middle

Seizing the middle means positioning at the centre of a value chain or network so that participants on either side must pass through you. The middle player becomes the default...

Simultaneous/Sequential

Games — in markets, negotiations, or competition — are either simultaneous (players act without knowing others' choices) or sequential (players move in order, observing earlier...

Symmetry of Ignorance

The symmetry of ignorance holds that in complex or novel problems, no single participant — designer, user, engineer, or executive — has sufficient knowledge to define the solution...

TANSTAAFL

TANSTAAFL — "There Ain't No Such Thing As A Free Lunch" — is the principle that every benefit has a cost, even when it isn't visible. Someone always pays: in money, time,...

Tiered Pricing

Tiered pricing offers a product or service at multiple price-and-feature levels so that different customer segments self-select into the tier that matches their willingness to...

3-6-3 Rule

The 3-6-3 Rule is the old banking joke: borrow at 3%, lend at 6%, and be on the golf course by 3pm. It describes the era when banking was a simple spread business — take deposits...

AD-AS Model

The AD-AS (Aggregate Demand–Aggregate Supply) model is the standard macroeconomic framework for understanding how the overall price level and total output are determined....

Cockroach Theory

The cockroach theory holds that when you see one piece of bad news, there are almost certainly more hiding behind it — just as seeing one cockroach in a kitchen implies many more...

Double Entry Accounting

Double entry accounting is the system in which every financial transaction is recorded in at least two accounts — a debit and a credit — so that the accounting equation (assets =...

Fisher Effect

Irving Fisher

The Fisher Effect states that the nominal interest rate equals the real interest rate plus expected inflation: i = r + π^e. Lenders demand compensation for the erosion of...

Luxury Paradox

Thorstein Veblen

The luxury paradox is that for certain goods, higher prices increase rather than decrease demand — the opposite of standard economics. Luxury goods function as status signals: the...

Minsky Moment

Hyman Minsky

A Minsky Moment is the sudden collapse of asset prices after a long period of growth fuelled by increasing speculation and debt. Named after economist Hyman Minsky, the core...

Negative Returns

Negative returns describe the zone beyond diminishing returns where additional input actively makes the outcome worse, not just less productive. Diminishing returns means each...

Pari-Mutuel System

In a pari-mutuel system, all bets are pooled together and the payout is determined by the share of the pool held by winning tickets — minus the house take. The odds aren't fixed...

Penny Problem Gap

The penny problem gap is the disproportionate behavioural cliff between free and any positive price — even one cent. The gap between $0 and $0.01 is vastly larger than the gap...

Phillips Curve

A.W. Phillips / Milton Friedman / Edmund Phelps

The Phillips Curve describes the observed inverse relationship between unemployment and inflation: when unemployment falls, wages and prices tend to rise, and vice versa....

Say's Law

Jean-Baptiste Say

Say's Law — "supply creates its own demand" — holds that the act of producing goods generates the income needed to purchase them. In its strong form: there can be no general...

Agenda-Setting Theory

Maxwell McCombs / Donald Shaw

Agenda-setting theory (Maxwell McCombs and Donald Shaw, 1972) holds that media may not tell people what to think, but it powerfully shapes what they think about. By choosing which...

Backwards Law

Alan Watts

The "backwards law" (often associated with Alan Watts and popularised in modern writing) is the idea that the more you pursue something directly — happiness, status, approval —...

Bias Against Null Results

Bias against null results is the systematic tendency to undervalue, ignore, or suppress findings that show no effect. Journals prefer "positive" results (something happened);...

Brandolini's Law

Giovanni Brandolini

Brandolini's Law (the "bullshit asymmetry principle") states that the amount of energy needed to refute nonsense is an order of magnitude larger than the energy needed to produce...

Chimpanzee Test

The Chimpanzee Test is a simplicity heuristic: if you can't explain a concept clearly enough that someone with no domain knowledge could grasp it, you probably don't understand it...

Controlled Placebo

A controlled placebo is the practice of comparing an intervention against an inert baseline (the placebo) to isolate the actual effect from the expected effect. Without a control,...

Cunningham's Law

Ward Cunningham

Cunningham's Law (attributed to Ward Cunningham, inventor of the wiki) states that the best way to get the right answer on the internet is not to ask a question — it's to post the...

Elon Musk's Law

Elon Musk

Elon Musk's Law (informal) is the principle that physics is the law, everything else is a recommendation. If something is physically possible, the only barriers are engineering,...

Gate's Law

Bill Gates

Gate's Law (often attributed to Bill Gates, closely related to Amara's Law) holds that we overestimate what we can achieve in two years and underestimate what we can achieve in...

Hotel Bathroom Principle

The Hotel Bathroom Principle is a heuristic: if the visible details are wrong, the hidden ones are likely worse. If a hotel bathroom is dirty, the kitchen is probably filthy. If...

Law of (Truly) Large Numbers

The Law of Truly Large Numbers states that with a large enough sample, any outrageous thing is likely to happen. Given millions of events, million-to-one coincidences occur daily....

Meta-Analysis

Meta-analysis is the practice of combining results from multiple independent studies to find stronger, more reliable patterns than any single study can provide. Individual studies...

Necessary Repeatability

Necessary repeatability is the principle that a result must be reproducible to be trusted. If an experiment, process, or outcome can't be repeated under similar conditions, it may...

Okrent's Law

Daniel Okrent

Okrent's Law (attributed to journalist Daniel Okrent) states that the pursuit of balance can create imbalance. When media or organisations try to present "both sides" of an issue...

P-hacking

P-hacking is the practice of manipulating statistical analysis — testing multiple hypotheses, adjusting variables, cherry-picking subgroups — until a result crosses the p < 0.05...

Peer Review

Peer review is the process of subjecting work — research, strategy, product decisions — to scrutiny by qualified, independent evaluators before it is accepted. In science, it is...

Planck's Principle

Max Planck

Planck's principle — often paraphrased as "science advances one funeral at a time" — holds that new ideas rarely win by converting their opponents. Instead, the old guard retires...

Reproducibility

Reproducibility is the requirement that a result can be independently obtained using the same methods. If you run the experiment again — different lab, different team — and get...

Reverse Engineer

Reverse engineering is the practice of taking an existing outcome — a product, a strategy, a competitor's success — and working backward to understand how it was built. Instead of...

Ribot's Law

Théodule Ribot

Ribot's law (Théodule Ribot, 1881) states that memory loss follows an inverse temporal gradient: recent memories are destroyed first, while older memories are the most resistant....

Schrodinger's Cat

Erwin Schrödinger

Schrödinger's cat is a thought experiment: a cat in a sealed box is simultaneously alive and dead until someone opens the box and observes. The point isn't about cats — it's about...

Skinner's Law

B.F. Skinner

Skinner's law — derived from B.F. Skinner's work in operant conditioning — holds that behaviour is a function of its consequences. Actions that are reinforced (rewarded) increase...

Systematic Review

A systematic review is a structured method for synthesising all available evidence on a question using pre-defined, transparent criteria. Unlike a casual literature scan or an...

The Gatekeepers

Gatekeepers are the individuals, institutions, or systems that control access to a resource, audience, or market. In media, editors decide what gets published. In venture,...

The Great Temptation

The great temptation is the pull toward expansion, diversification, or new opportunities at the expense of deepening what already works. It hits hardest after initial success —...

Veirordt's Law

Karl von Vierordt

Veirordt's law (Karl von Vierordt, 1868) describes a systematic error in human time perception: short durations are overestimated (they feel longer than they are), and long...

Weber-Fechner Law

Weber / Fechner

The Weber-Fechner law states that human perception of change is proportional to the relative magnitude of the stimulus, not the absolute magnitude. Adding one candle to a dark...

Worm's Eye View

A worm's eye view is the perspective from the ground — the lowest level of a system, closest to the actual work, the actual customer, the actual process. It is the opposite of the...

Accountability Partner

An accountability partner is someone who commits to monitoring and reinforcing your follow-through on stated goals. The mechanism is social: declaring a commitment to another...

Batching

Batching groups similar tasks into a single, uninterrupted block rather than scattering them across the day. The cognitive rationale is attention residue: every time you switch...

Breathwork

Breathwork uses deliberate breathing patterns to regulate the autonomic nervous system, shifting the body between sympathetic (alert) and parasympathetic (calm) states on demand....

Chunking

George Miller

Chunking compresses multiple pieces of information into a single cognitive unit, expanding the effective capacity of working memory. George Miller's research showed working memory...

Cold Exposure

Cold exposure — cold showers, ice baths, cold plunges — triggers a acute stress response that produces lasting physiological benefits. The mechanism: cold activates the...

Commitment Devices

A commitment device is a choice you make today that restricts your future options in order to enforce follow-through. The mechanism exploits loss aversion: by making failure...

Digital Minimalism

Cal Newport

Digital minimalism is a philosophy of technology use where you deliberately reduce digital tools to only those that strongly support your core values and priorities — and...

Dual N-Back

Jaeggi / Buschkuehl / Jonides / Perrig

Dual N-Back is a cognitive training task that exercises working memory by requiring you to track two independent streams of information simultaneously — typically a sequence of...

Elaborative Rehearsal

Elaborative rehearsal is the process of encoding new information by connecting it to existing knowledge rather than simply repeating it. Maintenance rehearsal (rote repetition)...

Energy Management

Energy management treats physical and mental energy — not time — as the fundamental resource to optimise. Time management assumes all hours are equal; energy management recognises...

Environment Design

Environment design is the practice of structuring your physical and digital surroundings to make desired behaviours effortless and undesired behaviours difficult. The insight is...

Implementation Intentions

Peter Gollwitzer

Implementation intentions are pre-decided if-then plans that specify when, where, and how you will perform a behaviour: "If situation X occurs, then I will do Y." The mechanism,...

Journaling

Journaling is the practice of writing regularly to clarify thinking, process emotions, track decisions, and build self-awareness over time. The mechanism is dual: writing forces...

Keystone Habits

Charles Duhigg

A keystone habit is a single behaviour that triggers a cascade of other positive behaviours without requiring separate willpower for each. Exercise is the canonical example:...

Memory Palace

A memory palace is a mnemonic technique where you mentally place items you want to remember at specific locations along a familiar route — your house, your commute, your office....

Method of Loci

The method of loci is a spatial mnemonic strategy — dating to ancient Greece — where information is encoded by associating each item with a specific physical location along a...

Note-Taking Systems

A note-taking system is a structured method for capturing, organizing, and retrieving information so that learning compounds over time. The value isn't in the act of writing —...

Pomodoro Technique

Francesco Cirillo

The Pomodoro Technique structures work into 25-minute focused intervals separated by 5-minute breaks, with a longer break after four cycles. The mechanism exploits two...

Single-Tasking

Single-tasking means doing one thing at a time with full attention. The case for it is neurological: the brain doesn't truly multitask on cognitive work — it switches between...

Speed Reading

Speed reading encompasses techniques designed to increase reading velocity while maintaining comprehension: skimming, chunking, reducing subvocalization, and strategic previewing....

Temptation Bundling

Katy Milkman

Temptation bundling pairs a behaviour you should do with a behaviour you want to do: only allow yourself the enjoyable activity while performing the important one. The term comes...

Time Boxing

Time boxing allocates a fixed, non-negotiable period to a task and stops when time expires — regardless of whether the task is finished. The mechanism exploits Parkinson's Law:...

Ultradian Rhythms

Ultradian rhythms are biological cycles of roughly 90–120 minutes that govern periods of high and low cognitive alertness throughout the day. Unlike circadian rhythms, which...

Visualization (HP)

Visualization — mental rehearsal of a desired outcome or process — engages many of the same neural pathways as physical performance. Neuroimaging studies show that vividly...

Algebra

Algebra is the practice of using symbols to represent unknown quantities and relationships, then manipulating those symbols to solve for unknowns. As a mental model, its power...

Anscombe's Quartet

Francis Anscombe

Anscombe's Quartet is a set of four datasets that share nearly identical summary statistics — same mean, variance, correlation, and regression line — yet look completely different...

Benford's Law

Benford's Law states that in many naturally occurring datasets, the leading digit is not uniformly distributed — the digit 1 appears as the first digit about 30% of the time,...

Berkson's Paradox

Berkson

Berkson's Paradox is a statistical phenomenon where two variables that are unrelated — or even positively correlated — in the general population appear negatively correlated when...

Confidence Intervals

A confidence interval expresses the range within which a true value likely falls, given the uncertainty in your measurement. A 95% confidence interval means that if you repeated...

Data Dredging

Data dredging — also called data fishing or data snooping — is the practice of searching through large datasets for statistically significant patterns without a prior hypothesis....

Dimensional Analysis

Dimensional analysis checks whether an equation or estimate makes sense by verifying that the units on both sides match. If you're calculating cost per customer and your answer...

Equivalence

Equivalence is the recognition that two things different in form are identical in function, value, or logical structure. In mathematics, it appears as equations, isomorphisms, and...

Error Bars

Error bars represent the range of uncertainty around a measured value. They show not just the estimate but how much that estimate could plausibly vary — encoding confidence,...

Frequentist Statistics

Frequentist statistics defines probability as the long-run frequency of events in repeated experiments. A coin has a 50% probability of heads not because of any belief about this...

Mean Median Mode

Mean, median, and mode are three ways to summarize the "center" of a dataset — and they tell different stories. The mean (average) includes every value, making it sensitive to...

Moderation

Moderation is the principle that the relationship between a variable and its outcome is often non-monotonic — more isn't always better, and the optimal point usually sits between...

Order of Approximation

Order of approximation is the practice of solving problems at the right level of precision for the decision at hand. A zeroth-order approximation ignores all nuance and gives a...

P-values

A p-value is the probability of observing data at least as extreme as the actual result, assuming the null hypothesis is true. It does not tell you the probability that your...

Permutations & Combinations

Permutations count the number of ways to arrange items when order matters. Combinations count selections when order doesn't. The distinction sounds academic but carries enormous...

Regression Analysis

Regression analysis models the relationship between variables — identifying how changes in one or more inputs predict changes in an output. Linear regression fits a straight line;...

Reliability of Case Evidence

Reliability of case evidence asks how much weight a single case — one customer story, one founder's success path, one market data point — should carry in forming beliefs....

Sampling

Sampling is drawing a subset from a larger population to make inferences about the whole. The power of sampling is efficiency — you don't need to survey every customer or test...

Statistical Significance

Statistical significance is the threshold at which an observed result is deemed unlikely enough under the null hypothesis to be considered "real" rather than random noise....

Stochastic Processes

A stochastic process is a system that evolves over time with inherent randomness — where the next state depends on the current state plus a random component. Stock prices,...

Surface Area

Surface area is the total exposed boundary between a system and its environment. In geometry, it determines how much of a solid contacts the outside world. In business, it...

Variability

Variability is the degree to which data points in a set differ from each other and from the central value. It's the spread, not the center. Two businesses can have identical...

Variance

Variance measures how far a set of outcomes spreads from the average. High variance means results swing widely; low variance means they cluster tight. The number itself is the...

36 Stratagems (Master Page)

The 36 Stratagems are a Chinese collection of military and political tactics compiled from centuries of warfare, diplomacy, and statecraft. Each stratagem is a pattern — a...

Boots on the Ground

Boots on the ground means committing real, physical presence to a situation rather than managing from a distance. In military terms, it's the difference between airstrikes and...

Call Your Bluff

Calling a bluff means forcing an opponent to prove a claimed position or follow through on a threat — exposing whether their leverage is real or fabricated. In military terms,...

Confusion

Confusion as a strategic tool means deliberately disrupting an opponent's ability to understand the situation, coordinate responses, or make coherent decisions. In military terms,...

Crippling

Crippling means targeting the critical capability that an opponent depends on — not to destroy them outright, but to degrade their ability to compete effectively. In military...

Decapitation

Decapitation means removing the leadership or decision-making centre of an opponent, collapsing their ability to coordinate and respond. In military terms, it's a strike on the...

Demoralization

Demoralization means breaking an opponent's will to fight rather than their ability to fight. It targets psychology — belief in the mission, confidence in leadership, trust that...

Distraction

Distraction means drawing an opponent's attention and resources toward a secondary objective so the primary effort succeeds unopposed. In military terms, it's a feint — a visible...

Division

Division means splitting an opponent's forces, coalition, or resources so they can't concentrate their strength. In military terms, it's maneuvering to separate an enemy army into...

Erosion

Erosion is the strategy of gradually wearing down an opponent's resources, position, or resolve through sustained, low-intensity pressure rather than decisive engagement. In...

Fear

Fear as a strategic tool means leveraging an opponent's anticipation of loss, pain, or failure to paralyse their decision-making or force concessions without direct engagement. In...

Fighting the Last War

Fighting the last war means applying strategies, structures, and assumptions that worked in a previous conflict to a fundamentally different new one. In military history, generals...

Flypaper Theory

Flypaper theory holds that it's better to attract and concentrate threats in a single, controlled location than to fight them spread across many. In military terms, the idea is to...

Fortification

Fortification means building defensive structures that make a position extremely costly to attack. In military terms, it's walls, trenches, and strongpoints that force attackers...

Overwhelm

Overwhelm means concentrating so much force, speed, or complexity on an opponent that their capacity to respond collapses. In military terms, it's attacking on multiple fronts...

Provocation

Provocation means deliberately goading an opponent into an emotional, hasty, or poorly calculated response that damages their own position. In military history, feigned retreats...

Punching Above Weight

Punching above weight means a smaller force achieving disproportionate impact against a larger, better-resourced opponent. In military terms, it's a small nation or unit...

Rumsfeld's Rule

Donald Rumsfeld

Rumsfeld's Rule categorises knowledge into four quadrants: known knowns (things we know we know), known unknowns (things we know we don't know), unknown unknowns (things we don't...

Sacrifice

Sacrifice means deliberately giving up something valuable now to gain a larger strategic advantage later. In military history, it's trading a position, unit, or battle to win the...

Seeing the Front

Seeing the front means going to where the action is — the actual point of contact with customers, competitors, or operations — rather than relying on filtered reports and...

Siege War

Siege warfare means surrounding and isolating an opponent's position, cutting off their supplies, reinforcements, and options until they're forced to capitulate without a direct...

Speed

Speed as a strategic principle means that the rate of decision-making and execution is itself a competitive advantage — independent of the quality of any individual decision. In...

Stop the Bleeding

Stop the bleeding means immediately stabilising a deteriorating situation before attempting any recovery or improvement. In military medicine, you stop arterial bleeding before...

Terrorism

Terrorism as a strategic model describes the use of dramatic, high-visibility attacks designed to generate disproportionate psychological impact relative to actual damage. The...

Trench War

Trench warfare describes a competitive stalemate where both sides are deeply entrenched in their positions, neither able to gain meaningful ground, and every advance comes at...

Turtling

Turtling means retreating into an extremely defensive posture — prioritising protection and survival over any form of offensive action. In military terms, it's pulling forces...

Winning Battle but Losing War

Winning the battle but losing the war means achieving tactical victories that come at such a high cost — in resources, attention, relationships, or strategic position — that they...

Zero-tolerance Policy

A zero-tolerance policy means establishing absolute rules with automatic, severe consequences for any violation — no exceptions, no judgment calls, no grey areas. In military...

Alloying

Alloying is the process of combining two or more elements to create a material with properties superior to any individual component. Bronze is stronger than copper or tin alone....

Atomic Theory

Everything complex is built from a finite set of simple, indivisible components. In physics, all matter reduces to atoms — a small periodic table produces every substance in the...

Baton Passing

In relay racing, the baton pass is the most critical moment — where speed is gained or lost. The metaphor maps directly to organisations: transitions between roles, teams, phases,...

Copernican Principle

Nicolaus Copernicus

The Copernican Principle holds that you are not special — your position, timing, or perspective is not privileged. Just as Copernicus showed Earth wasn't the centre of the...

Determinism

Determinism holds that every event is the inevitable result of prior causes. In physics, given perfect knowledge of initial conditions, the future is theoretically predictable....

Electromagnetism

Electromagnetism describes how electric and magnetic fields interact — invisible forces that attract, repel, and propagate at a distance. In physics, it's one of the four...

Foundational Species

In ecology, a foundational species creates and maintains the habitat that allows an entire ecosystem to exist. Coral builds reefs; old-growth trees create forest canopies. Remove...

Herd Immunity

Herd immunity occurs when enough members of a group are protected against a threat that the threat can no longer spread effectively — even to those who aren't individually...

Heredity

Heredity is the transmission of traits from one generation to the next. In biology, DNA carries information that determines physical characteristics, predispositions, and...

Kinetics

Kinetics is the study of rates — how fast reactions occur, not just whether they occur. In chemistry, a reaction can be thermodynamically favourable but kinetically slow: it will...

Memetic Theory of Conflict

Rene Girard

Mimetic theory, originated by Rene Girard, proposes that conflict arises not from scarcity or rational disagreement but from imitative desire — people want the same things because...

Memetic Theory of Desire

Rene Girard

Rene Girard’s mimetic theory holds that human desire is not autonomous — we don’t want things because of their intrinsic value but because other people want them. Desire is...

Molecular Shape

In chemistry, a molecule’s shape determines its function. The same atoms arranged differently produce radically different substances — carbon arranged as graphite is soft and...

Nature vs Nurture

The nature vs nurture debate asks whether traits are determined by genetics (nature) or environment (nurture). In biology, the answer is both — genes set a range of potential, and...

Peak Oil

M. King Hubbert

Peak oil describes the point at which extraction of a finite resource reaches its maximum rate, after which production irreversibly declines. The concept, introduced by geologist...

Polarity

Polarity describes the existence of two opposing but interdependent forces — positive and negative, attraction and repulsion, growth and stability. In physics, charged particles...

Potential

Potential is stored capacity — energy, ability, or opportunity that exists but hasn't yet been converted into action or output. In physics, a boulder at the top of a hill holds...

Principle of Minimum Energy

The Principle of Minimum Energy states that systems naturally settle into the configuration requiring the least energy to maintain. Water flows downhill. Electrons occupy the...

Quantum Mechanics

Quantum mechanics describes a world where outcomes are fundamentally probabilistic, not deterministic. At the subatomic level, particles don't have fixed states until they're...

Replication

Replication is the process of copying a successful pattern with high fidelity. In biology, DNA replicates to build organisms; errors in replication cause mutations. In business,...

Resonant Frequency

Every system has a natural frequency at which it vibrates most efficiently. Apply energy at that frequency and the system amplifies — small inputs produce massive outputs. Apply...

Reward System

The reward system is the brain's built-in mechanism for reinforcing behaviour. Dopamine — the neurotransmitter at its core — doesn't signal pleasure; it signals anticipated...

Self-Preservation

Self-preservation is the fundamental biological drive to maintain one's existence. Every organism — from bacteria to corporations — develops mechanisms to detect threats and take...

Shannon-Hartley Law

Shannon & Hartley

The Shannon-Hartley theorem defines the maximum rate at which information can be transmitted over a communication channel with a given bandwidth and noise level. The formula is...

Sustainability

Sustainability is the capacity of a system to maintain itself over time without depleting the resources it depends on. In ecology, an ecosystem is sustainable when consumption...

The Chemical Bond

A chemical bond is the force that holds atoms together to form molecules. The bond forms because the combined state is more stable — lower energy — than the atoms existing...

The Chemical Reaction

A chemical reaction occurs when substances combine or break apart to form something new. Reactants go in; products come out. The key insight: reactions require specific conditions...

Viscosity

Viscosity is a fluid's resistance to flow. High-viscosity fluids like honey move slowly; low-viscosity fluids like water flow freely. As a mental model, viscosity describes the...

Agnosticism

Agnosticism is the intellectual position that some questions cannot be answered with certainty — and that honest acknowledgment of this uncertainty is more valuable than false...

Arrow's Impossibility Theorem

Kenneth Arrow

Arrow's Impossibility Theorem proves that no ranked voting system can perfectly translate individual preferences into a collective decision while satisfying a small set of...

Categorical Imperative

Kant

The Categorical Imperative, Kant's foundational ethical principle, states: act only according to rules you could will to be universal laws. Before taking any action, ask: what...

Common Law

Common law is a legal system built not from top-down legislation but from the accumulated weight of judicial decisions over time. Each ruling becomes a precedent that shapes...

Condorcet Paradox

Marquis de Condorcet

The Condorcet Paradox shows that collective preferences can be irrational even when every individual's preferences are perfectly rational. If voters prefer A over B, B over C, and...

Constructivism

Constructivism holds that knowledge, meaning, and social reality are not discovered but constructed through human interaction, language, and shared interpretation. There is no...

Decline of Violence

Steven Pinker

Despite the constant drumbeat of alarming headlines, violence has declined dramatically over centuries and millennia — in every measurable form. Homicide rates, deaths in warfare,...

Distributive vs Procedural Justice

Justice has two faces. Distributive justice asks whether outcomes are fair — did everyone get what they deserve? Procedural justice asks whether the process was fair — were the...

Duty of Care

Duty of care is the legal and moral obligation to act with reasonable concern for the safety and well-being of others who could be affected by your actions or decisions. In law,...

Duverger's Law

Maurice Duverger

Duverger's Law states that single-member district, winner-take-all electoral systems tend to produce two-party systems, while proportional representation tends to produce...

Extremely Intense Ideology

Charlie Munger

Extremely intense ideology is the tendency for strongly held belief systems to distort thinking, override evidence, and make their adherents confidently wrong. Charlie Munger...

Futarchy

Robin Hanson

Futarchy is a proposed governance system where we "vote on values, bet on beliefs." Citizens define the goals they care about through democratic processes, then prediction markets...

Historical Wisdom

Historical wisdom is the practice of using the accumulated lessons of history as a decision-making tool. It rests on the observation that while specific events don't repeat, the...

Horseshoe Theory

Horseshoe theory proposes that the political spectrum is not a straight line from left to right but a horseshoe — with the extreme left and extreme right curving toward each...

Law of Non-Contradiction

Aristotle

The law of non-contradiction states that a proposition cannot be both true and false at the same time and in the same respect. It is one of the foundational axioms of logic, first...

Limited Hangout

A limited hangout is a strategic disclosure of partial truth to prevent the full truth from emerging. When concealment is no longer viable, the actor reveals enough damaging...

Negligence

Negligence is the failure to exercise the level of care that a reasonable person would exercise in the same circumstances, resulting in harm to others. It sits at the intersection...

Political/Government Failure

Political or government failure occurs when government intervention in markets or society produces outcomes worse than the problem it was meant to solve. Just as markets can fail...

Presumption of Innocence

The presumption of innocence is the principle that any person accused must be considered innocent until proven guilty by sufficient evidence. In law, it places the burden on the...

Reasonable Doubt

Reasonable doubt is the threshold of certainty required before acting on a conclusion — the standard that separates justified conviction from premature judgment. In criminal law,...

Sayre's Law

Sayre's Law states that "in any dispute, the intensity of feeling is inversely proportional to the value of the issues at stake." The less that matters, the more fiercely people...

State Capture

State capture is the process by which private interests systematically redirect public institutions to serve their own ends — not through occasional lobbying but through...

The Golden Mean

Aristotle

The golden mean is Aristotle's principle that virtue lies between two extremes — excess and deficiency. Courage is the mean between recklessness and cowardice. Generosity is the...

The Magic Ratio

John Gottman / Marcial Losada / Emily Heaphy

The magic ratio — derived from John Gottman's research on marriages and later extended to teams — states that stable, high-performing relationships require a minimum ratio of...

The Meaning of Life

Viktor Frankl

The meaning of life — as a mental model, not a metaphysical quest — is the recognition that humans perform at their highest level when their work connects to a purpose they find...

The Platinum Rule

The platinum rule is the upgrade to the golden rule: instead of "treat others as you would want to be treated," it says "treat others as they want to be treated." The distinction...

The Reasonable Person

The reasonable person is a legal and philosophical standard: an imaginary individual of ordinary prudence, care, and judgment, used to measure whether someone's behavior was...

Third Rail

A third rail is a topic, policy, or decision so politically dangerous that touching it destroys you — named after the electrified rail in subway systems that kills on contact. In...

Three Buckets of History

The three buckets of history framework sorts historical events into three categories: things that have happened before and will happen again, things that have happened before but...

Abstract Blindness

Abstract blindness is the tendency to overlook or undervalue abstract factors — probabilities, systemic causes, long-term effects — because concrete, vivid, or immediate...

Ambiguity Bias

Ambiguity bias is the tendency to prefer options where the probability of a favorable outcome is known over options where the probability is unknown — even when the unknown option...

Anecdotal Fallacy

The anecdotal fallacy is using a personal experience or single example as proof of a general claim — substituting a vivid story for statistical evidence. "My uncle smoked his...

Appeal to Novelty

Appeal to novelty is the assumption that newer is better — that the latest idea, tool, or method is superior because it is recent. Recency is mistaken for progress. The core idea:...

Association Bias

Association bias is judging something by what it's linked to — people, brands, contexts — rather than by its own attributes. We transfer feelings and beliefs from one thing to an...

Aumann's Agreement Theorem

Robert Aumann

Aumann's agreement theorem says that two rational agents who share a common prior and whose posteriors are common knowledge cannot agree to disagree — they must converge to the...

Authority Bias

Authority bias is the tendency to overweight the views or orders of people we see as authorities — titles, credentials, status — and to underweight the content of what they say....

Automation Bias

Automation bias is the tendency to over-trust automated systems — algorithms, dashboards, tools — and to under-check or override our own judgment when the system suggests an...

Belief Bias

Belief bias is the tendency to judge an argument by whether we agree with the conclusion rather than by the quality of the reasoning. We accept valid-looking arguments that...

Blind Spot

Blind spot (in psychology) is the failure to see one's own biases and errors while readily seeing them in others. We have a literal blind spot for our own judgment flaws. The core...

Blindspot Bias

Blindspot bias is the belief that we are less biased than other people — that we see the world more objectively while others are swayed by bias. We spot bias in others easily and...

Bright Spots

Chip Heath / Dan Heath

Bright spots are the positive outliers — people, teams, or cases that succeed where others fail under similar conditions. Instead of only studying failure or the average, study...

Bucket Error

A bucket error occurs when you misclassify something by putting it in the wrong mental category — and then reason about it based on the category rather than the thing itself. The...

Burnout

Burnout is the state of chronic physical and emotional exhaustion caused by prolonged stress without adequate recovery — characterized by three dimensions: exhaustion, cynicism,...

Catharsis

Aristotle

Catharsis is the release of strong emotions through expression, producing a sense of relief or renewal. Aristotle introduced it to explain why audiences leave tragedies feeling...

Caveman Syndrome

Caveman Syndrome is the recognition that our brains evolved for a world radically different from the one we now inhabit. The mental hardware running your decisions was optimised...

Change Bias

Change Bias is the systematic tendency to either overestimate or underestimate the impact of a change, depending on your relationship to it. Those proposing a change tend to...

Cheerleader Effect

The Cheerleader Effect is the cognitive bias where individuals appear more attractive, competent, or impressive when presented as part of a group than when evaluated alone. The...

Cherry-Picking

Cherry-picking is the practice of selecting only the evidence that supports your pre-existing conclusion while ignoring evidence that contradicts it. Unlike confirmation bias —...

Cognitive Scope Limitation

Cognitive Scope Limitation is the recognition that the human mind has a finite capacity for the range and complexity of problems it can hold simultaneously. We struggle to think...

Compassion Face

Compassion Face is the phenomenon where people unconsciously mirror empathetic facial expressions and body language to signal understanding and care — regardless of whether they...

Conflict

Conflict is the inevitable tension that arises when individuals, teams, or organisations have incompatible goals, values, or interpretations. Most people treat conflict as a...

Congruence Bias

Congruence Bias is the tendency to test a hypothesis exclusively by searching for evidence that confirms it, rather than by attempting to falsify it or testing alternative...

Conservatism Bias

Conservatism Bias is the tendency to insufficiently update beliefs when presented with new evidence. Even when confronted with data that should significantly change your view, you...

Context Effect

The Context Effect is the principle that the environment, setting, and surrounding information fundamentally alter how people perceive, evaluate, and decide. The same product...

Continued Influence Effect

The Continued Influence Effect describes how information that has been clearly corrected or retracted continues to shape thinking and decision-making. Even after you learn that an...

Courtesy Bias

Courtesy Bias is the tendency to give opinions that are more socially acceptable or agreeable than one's true assessment, particularly in face-to-face settings. People tell you...

Cryptomnesia

Cryptomnesia is the phenomenon where a forgotten memory returns without being recognised as such — you experience a recalled idea as if it were an original thought. You read...

Cult Indoctrination

Cult Indoctrination describes the systematic process by which individuals are drawn into extreme group loyalty through a predictable sequence of psychological techniques:...

Declinism

Declinism is the belief that society, an institution, or a situation is getting worse — and that the past was better than it actually was. It combines rosy retrospection...

Distinction Bias

Distinction bias is the tendency to overvalue differences between options when evaluating them side by side, compared to how we'd experience them separately. In joint evaluation...

Duration Neglect

Duration neglect is the psychological finding that people judge an experience primarily by its most intense moment and its ending, largely ignoring how long it lasted. A...

Echo Chamber Effect

The echo chamber effect is the amplification of beliefs that occurs when people are surrounded only by others who share their views. Dissenting information is absent, agreement is...

Effort Justification

Effort justification is the tendency to value outcomes more highly when we've worked hard to achieve them — regardless of the outcome's actual quality. If it was painful to get,...

Egocentric Bias

Egocentric bias is the tendency to overestimate our own contribution, perspective, or importance relative to others. We remember our inputs more vividly, weigh our opinions more...

Eloquence

Eloquence bias is the tendency to judge the quality of an idea by how well it is expressed rather than by its actual merit. A beautifully articulated argument feels more true; a...

Emotional Contagion

Emotional contagion is the automatic, often unconscious transfer of emotions between people. Moods spread — anxiety, enthusiasm, frustration, calm — through facial expressions,...

Exaggerated Expectation

Exaggerated expectation is the tendency to expect outcomes — whether positive or negative — to be more extreme than they actually turn out to be. We overshoot in both directions:...

Excessive Fairness Bias

Excessive fairness bias is the tendency to prioritise equal treatment over optimal outcomes — distributing resources, credit, or attention evenly when the situation demands...

Extremeness Aversion

Extremeness aversion is the tendency to avoid the most extreme option in a set, regardless of its actual merit. When choosing between three options, people disproportionately...

False Consensus

False consensus is the tendency to overestimate how many other people share our beliefs, values, and behaviours. We assume our views are more common and representative than they...

False Memory

False memory is the phenomenon where we recall events that didn't happen or recall real events differently from how they occurred. Memory is not a recording — it's a...

False Precision

False precision is presenting a number or estimate with more specificity than the underlying data supports. Saying "the market is $4.27 billion" when the real answer is "roughly...

First-conclusion Bias

First-conclusion bias is the tendency to accept the first explanation or solution that comes to mind and stop searching for better ones. Our brains are wired to resolve...

Focalism

Kahneman

Focalism — also called the focusing illusion — is the tendency to overweight a single aspect of an event when making predictions or evaluations. When estimating how a new hire,...

Forecast Bias

Forecast Bias is the systematic tendency for predictions to skew in a consistent direction — typically toward overconfidence, optimism, or the continuation of current trends. It...

Gateway Drug Theory

Gateway Drug Theory proposes that exposure to a mild experience lowers the threshold for progressively more intense versions of that experience. In its original context, the...

Group Attribution Error

Group Attribution Error is the tendency to assume that the characteristics or decisions of a group reflect the preferences of every individual within it — or that a single...

Humor Effect

The Humor Effect is the cognitive phenomenon where humorous information is remembered better than non-humorous information. Jokes, wit, and playful framing create stronger memory...

Hypernovelty

Hypernovelty describes the modern condition of being surrounded by an endless stream of new stimuli — news, notifications, content, products, trends — that hijacks the brain's...

Ideological Bias

Ideological Bias is the tendency to interpret information, evaluate evidence, and make decisions through the lens of a pre-existing belief system rather than on the merits. When...

Illusion of Skill

The Illusion of Skill is the mistaken belief that consistent patterns in outcomes reflect genuine expertise rather than luck, randomness, or environmental factors. Professionals...

Illusion of Transparency

The Illusion of Transparency is the belief that your internal states — intentions, emotions, knowledge — are more apparent to others than they actually are. You think your...

Illusion of Validity

Kahneman / Tversky

The Illusion of Validity is the cognitive bias where high confidence in a judgment persists even when the evidence underlying that judgment is known to be unreliable. When...

Impact Bias

Impact Bias is the tendency to overestimate the intensity and duration of emotional reactions to future events — both positive and negative. We predict that a major win will make...

Inattentional Bias

Inattentional Bias — sometimes called inattentional blindness — is the failure to notice fully visible and relevant information because your attention is directed elsewhere. The...

Inconsistency-Avoidance

Charlie Munger

Inconsistency-Avoidance is the brain's deep resistance to holding or acting on contradictory beliefs, ideas, or behaviours. To conserve energy and maintain a stable self-concept,...

Information Bias

Information Bias is the tendency to seek more information even when it will not change the decision. It manifests as the belief that more data always leads to better outcomes —...

Ingroup Bias

Ingroup Bias is the automatic tendency to favour members of your own group — giving them more trust, more benefit of the doubt, more resources, and more favourable interpretations...

Interpretation & Reinterpretation

Interpretation & Reinterpretation describes the mind's constant process of assigning meaning to events — and then revising that meaning when new information, new context, or new...

Jealousy/Envy Tendency

Charlie Munger

Jealousy/Envy Tendency is the deep-seated human impulse to feel pain at the success or advantages of others — particularly those we perceive as similar to ourselves. Envy targets...

Least Effort Principle

The Least Effort Principle states that when faced with multiple paths to a goal, humans (and most organisms) will reliably choose the one requiring the least total work —...

Leveling & Sharpening

Leveling & Sharpening describes the systematic distortion that occurs when information passes through memory or communication. Leveling is the loss of detail — nuance, context,...

Liking/Loving Bias

Liking/Loving Bias is the tendency to distort your judgement in favour of people, products, or ideas you like or love. When you like someone, you overvalue their virtues,...

Ludic Fallacy

Nassim Nicholas Taleb

The Ludic Fallacy — from the Latin ludus, meaning game — is the mistake of applying the clean, well-defined rules of games and models to the messy, open-ended reality of the real...

Masked Man Fallacy

The Masked Man Fallacy — also called the intensional fallacy — occurs when someone assumes that because they know something under one description, they must know it under all...

Mental Simulation

Mental Simulation is the cognitive process of imagining how events will unfold — running scenarios in your mind before they happen. It's how founders envision product launches,...

Mere Exposure Effect

Robert Zajonc

The Mere Exposure Effect is the phenomenon where repeated exposure to a stimulus — a face, a brand, a song, an idea — increases your preference for it, independent of any new...

Momentum Bias

Momentum Bias is the tendency to continue a course of action primarily because it's already in motion — not because ongoing evidence supports it. Once energy, resources, and...

Multiple Tendencies

Charlie Munger

Multiple Tendencies refers to the reality that human behaviour is rarely driven by a single psychological force. At any given moment, several cognitive biases, emotional drives,...

Negativity Bias

Negativity Bias is the tendency for negative experiences, information, and emotions to have a disproportionately larger effect on psychological states and decisions than neutral...

Normalcy Bias

Normalcy Bias is the tendency to assume that because something has never happened before, it won't happen — or that because things have always been a certain way, they'll continue...

Omission Bias

Omission Bias is the tendency to judge harmful actions as worse than equally harmful inactions — to feel that doing something that causes damage is morally and psychologically...

Optimism Bias

Optimism Bias is the tendency to overestimate the likelihood of positive outcomes and underestimate the likelihood of negative ones — particularly for events involving yourself....

Optimistic Probability Bias

Optimistic Probability Bias is the specific tendency to overestimate the probability of favourable events and underestimate the probability of unfavourable ones. While Optimism...

Outcome Bias

Outcome Bias is the tendency to judge the quality of a decision based on its outcome rather than the quality of the decision-making process at the time it was made. A risky bet...

Paradox of Knowledge

The Paradox of Knowledge is the observation that the more you learn about a subject, the more you realise how much you don't know — and conversely, the less you know, the more...

Paranoia

Andy Grove

Paranoia, in the business context, is a heightened state of vigilance toward threats — real and imagined — that can be either debilitating or productive depending on how it's...

Pareidolia

Pareidolia is the tendency to perceive meaningful patterns — particularly faces, shapes, or signals — in random or ambiguous stimuli. You see a face in the clouds, a trend in...

Peltzman Effect

Sam Peltzman

The Peltzman Effect, named after economist Sam Peltzman, is the observation that safety measures often fail to reduce total harm because people compensate for increased safety by...

Pessimism Bias

Pessimism Bias is the tendency to overestimate the likelihood and severity of negative outcomes. While optimism bias skews projections upward, pessimism bias skews them downward —...

Physical/Psychological Pain Bias

Physical/Psychological Pain Bias describes the tendency for the anticipation and experience of pain — whether physical or emotional — to dominate decision-making beyond what...

Placement Bias

Placement Bias is the tendency for the position of information — where it appears in a sequence, on a page, in a list, or in a physical space — to disproportionately influence...

Positivity Effect

The Positivity Effect is the tendency — especially pronounced with age and experience — to attend to, remember, and favour positive information over negative information. Seasoned...

Precision Bias

Precision Bias is the tendency to treat precise-sounding numbers as more credible and reliable than round ones, even when the underlying data doesn't support that level of...

Prejudice

Prejudice is a pre-formed judgment about a person, group, or situation based on category membership rather than individual evidence. It operates as a cognitive shortcut: instead...

Present Bias

Present Bias is the tendency to overweight immediate rewards relative to future ones, beyond what rational discounting would justify. Given a choice between $100 today and $120 in...

Primacy Effect

The Primacy Effect is the tendency for the first information received to disproportionately shape opinions, memory, and judgment. In a list of traits, the first ones mentioned...

Pro-innovation Bias

Pro-innovation Bias is the tendency to overvalue new innovations, assuming they should be widely adopted while underestimating their limitations, costs, and the adequacy of...

Procrastination

Procrastination is the act of delaying important tasks in favour of less important but more immediately comfortable ones — despite knowing the delay will cost you. It's not...

Projection Bias

Projection Bias is the tendency to assume that others share your current preferences, beliefs, emotions, or mental state — and that your own future self will feel the same way you...

Pseudocertainty Effect

Kahneman / Tversky

The Pseudocertainty Effect occurs when people treat an outcome as certain even though it's merely probable, because the decision has been mentally separated into stages. In a...

Publication Bias

Publication Bias is the systematic tendency for studies with positive, significant, or novel results to get published while studies with null, negative, or replicative results...

Rashomon Effect

Akira Kurosawa

The Rashomon Effect — named after Akira Kurosawa's film — describes how the same event produces multiple contradictory but individually plausible accounts, each shaped by the...

Reason-Respecting Tendency

Ellen Langer

The Reason-Respecting Tendency is the human inclination to comply more readily with a request when a reason is provided — even if the reason is trivial or circular. Ellen Langer's...

Recency Illusion

The Recency Illusion is the belief that something you've only recently noticed must itself be recent. You learn a new word and suddenly hear it everywhere; you discover a business...

Reciprocation Bias

Reciprocation Bias is the deep-seated compulsion to return favours, gifts, and concessions — even when the original gesture was uninvited, unwanted, or strategically calculated....

Reductive Bias

Reductive Bias is the tendency to oversimplify complex, multi-causal phenomena by attributing them to a single cause or a simple explanation. When a product fails, it must have...

Restraint Bias

Restraint Bias is the tendency to overestimate your ability to control impulsive behaviour. People who believe they have strong willpower expose themselves to more temptation —...

Reward & Punishment

Reward and Punishment is the foundational behavioural principle that organisms repeat behaviours that are rewarded and avoid behaviours that are punished. It sounds elementary,...

Ringelmann Effect

Max Ringelmann

The Ringelmann Effect is the finding that individual effort decreases as group size increases. In a tug-of-war experiment, each person pulls less hard when more people are on the...

Sapir-Whorf Hypothesis

Edward Sapir / Benjamin Lee Whorf

The Sapir-Whorf Hypothesis proposes that the language you use shapes how you think — not just how you communicate, but what you're capable of perceiving and reasoning about. In...

Scarcity Bias

Scarcity Bias is the tendency to assign greater value to things that are scarce, limited, or dwindling in availability — regardless of their objective worth. When something...

Self-Enhancement Bias

Self-Enhancement Bias is the tendency to perceive yourself as above average on desirable traits — intelligence, skill, ethics, driving ability — even when statistical reality...

Self-Handicapping

Self-Handicapping is the strategy of creating obstacles to your own performance so that failure can be attributed to those obstacles rather than to lack of ability. A student who...

Self-Serving Bias

Self-Serving Bias is the tendency to attribute your successes to internal factors — talent, effort, intelligence — while blaming your failures on external circumstances — bad...

Self-consistency Bias

Self-consistency Bias is the tendency to perceive your past beliefs, attitudes, and behaviours as more consistent with your current ones than they actually were. People...

Self-relevance Effect

The self-relevance effect is the tendency for people to process and remember information more deeply when it relates to them personally. Messages framed around "you" and "your...

Semmelweis Reflex

Ignaz Semmelweis

The Semmelweis Reflex is the automatic tendency to reject new evidence or knowledge because it contradicts established norms, beliefs, or paradigms. Named after Ignaz Semmelweis —...

Serial Recall Effect

The serial recall effect describes how the position of information in a sequence determines how well it's remembered. Items at the beginning (primacy) and end (recency) of a list...

Simplicity Bias

Simplicity bias is the tendency to prefer simple explanations and solutions even when the situation is genuinely complex. Unlike Occam's Razor — which recommends parsimony as a...

Sleeper Effect

The sleeper effect is the phenomenon where a message becomes more persuasive over time as the recipient forgets the source but retains the content. Initially, a low-credibility...

Social Comparison Bias

Social comparison bias is the tendency to favour or disfavour people based on how they compare to us — particularly resisting those who are perceived as superior in areas where we...

Social Desirability Bias

Social desirability bias is the tendency for people to answer questions and present themselves in ways they believe will be viewed favourably by others — rather than answering...

Stress-Influence Bias

Stress-influence bias is the tendency for acute stress to distort decision-making — narrowing attention, amplifying loss aversion, and collapsing complex trade-offs into binary...

Subjective Validation

Subjective validation is the tendency to perceive a statement or piece of information as true if it holds personal meaning or significance — regardless of whether it's objectively...

Testing Effect

The testing effect is the finding that actively retrieving information from memory strengthens long-term retention far more than passively reviewing the same material. Testing...

The Onion Brain

The Onion Brain is the model that human cognition operates in layers — from fast, instinctive reactions at the core to slow, deliberate reasoning at the surface. Each layer...

Threat Lockdown

Threat lockdown is the cognitive state where a perceived threat causes the brain to narrow focus, suppress peripheral information, and lock onto the danger source. While useful...

Three Men Make A Tiger

Three Men Make A Tiger is the ancient Chinese proverb that illustrates how repetition from multiple sources creates belief — even in absurdities. If one person tells you there's a...

Time-Saving Bias

Time-saving bias is the tendency to overestimate the time saved when increasing speed from a slow pace and underestimate the time saved when increasing from an already fast pace....

Trait Ascription Bias

Trait ascription bias is the tendency to view oneself as relatively variable in personality and behaviour while viewing others as more predictable and fixed. You see your own...

Turkey Illusion

Nassim Taleb

The turkey illusion — derived from Nassim Taleb's parable — describes the danger of inferring safety from a long history of stability. A turkey is fed every day for 1,000 days,...

Ultimate Attribution Error

The ultimate attribution error extends the fundamental attribution error to groups. When members of our ingroup succeed, we attribute it to character and ability. When they fail,...

Uncertainty Avoidance

Uncertainty avoidance is the degree to which people feel threatened by ambiguous or unknown situations and create structures — rules, rituals, processes — to reduce that...

Victim-blaming

Victim-blaming is the tendency to attribute fault to the person who suffered harm rather than to the circumstances or the perpetrator. It stems from the psychological need to...

Vividness Illusion

The vividness illusion is the tendency to give disproportionate weight to vivid, emotionally charged, or easily imagined information — while underweighting pallid but...

Zero-sum Heuristic

The zero-sum heuristic is the default cognitive shortcut that treats most interactions as zero-sum — where one party's gain must come at another's expense — even when the...

Analytical Honesty

Analytical honesty is the discipline of letting data tell you what is true rather than what you want to hear. It means confronting uncomfortable metrics, acknowledging when a...

Bottlenecks (Systems)

A bottleneck is the narrowest point in a system — the constraint that limits the throughput of everything downstream. In a factory, it's the slowest machine. In an organisation,...

Cessation

Cessation is the deliberate act of stopping — ending a process, product, initiative, or habit that no longer serves the system. Most systems have a bias toward continuation: once...

Change

Change is the transition of a system from one state to another. As a mental model, the insight isn't that change happens — it's that systems resist it. Every stable system has...

Context

Context is the surrounding information that determines how a signal is interpreted. The same data point, decision, or behaviour means entirely different things depending on the...

Deconstruction

Deconstruction is the systematic dismantling of a complex whole into its component parts to understand how it works, why it works, and where it fails. Unlike simple analysis,...

Environment

Environment is the set of external conditions that surround and influence a system. As a mental model, it recognises that behaviour is shaped more by the environment it occurs in...

Garbage In Garbage Out

Garbage in, garbage out (GIGO) states that the quality of a system's output is fundamentally limited by the quality of its inputs. No amount of processing, analysis, or...

Humanization

Humanization is the practice of reintroducing human perspective into systems that have become abstracted. As organisations scale, they naturally abstract away individuals —...

KPI

A Key Performance Indicator is a quantifiable metric chosen to represent the health or progress of a system toward its goals. The power of KPIs lies in focus — they force an...

Margin of Error

Margin of error is the range within which the true value of a measurement is likely to fall. Every measurement, estimate, and forecast has one — whether stated or not. The model...

Measurement

Measurement is the act of assigning a number to an attribute of reality. As a mental model, the key insight is that measurement is never neutral — it selects, simplifies, and...

Norms

Norms are the unwritten rules that govern behaviour within a system. They are distinct from formal rules or policies — norms emerge from repeated behaviour, social reinforcement,...

Process Overhead

Process overhead is the cost — in time, energy, and attention — of maintaining the processes themselves rather than doing the work the processes are meant to enable. Every...

Progressive Load

Progressive load is the principle of introducing complexity, demand, or change to a system gradually rather than all at once. Systems — biological, organisational, or mechanical —...

Ratio

A ratio expresses the relationship between two quantities, revealing proportionality that absolute numbers hide. Revenue means little without knowing the cost to generate it....

Renormalization Group

The renormalization group is a framework for understanding how a system's behaviour changes — or doesn't — as you shift the scale at which you observe it. Originating in physics,...

Selection Test

A selection test is any mechanism that filters inputs into a system based on defined criteria. Hiring processes, market competition, college admissions, and immune responses are...

Spring-Loading

Spring-loading is the practice of storing energy, resources, or capability in advance so that when an opportunity or trigger arrives, the system can release force disproportionate...

Sustainable Growth Cycle

A sustainable growth cycle is a self-reinforcing loop where growth generates the resources needed to fuel further growth — without depleting the system's foundation. Unlike...

The Middle Path

The middle path is the principle that optimal system performance often lies between extremes rather than at either pole. Originating in Buddhist philosophy and echoed in...

Tolerance

Tolerance is the acceptable range of deviation a system can absorb before performance degrades or failure occurs. Every system has tolerances — the variation in inputs,...

Typicality

Typicality is the degree to which an instance represents the central tendency of a category. The more typical something is, the more it resembles the average case. As a mental...

Uncertainty

Uncertainty is the condition of incomplete knowledge about the current state, future outcomes, or causal relationships within a system. Unlike risk — which can be quantified with...

Hedgehog Concept

Jim Collins's framework from Good to Great: find the intersection of what you can be the best in the world at, what drives your economic engine, and what you are deeply passionate about. The companies that made the leap from good to great found this intersection and pursued it with relentless discipline.

Leverage

Multiply your output with labor, capital, or products with zero marginal cost.

Pathos

Pathos is the appeal to emotion — one of Aristotle's three modes of persuasion alongside ethos (credibility) and logos (logic). Pathos works by creating an emotional connection between the speaker and the audience: empathy, fear, hope, anger, or joy. It is the most powerful short-term persuasion tool because decisions are made emotionally before they are justified logically. In business, great storytelling, brand identity, and crisis communication all rely heavily on pathos. Steve Jobs's product launches were masterclasses in pathos — he made you feel the problem before he revealed the solution. The risk of pathos is manipulation: appealing to emotion without substance erodes trust over time. The best communicators use pathos to open the door, then walk through it with logos.

Porter's Five Forces

Five competitive forces that determine why some industries are profitable and others are not.

Stockdale Paradox

Named after Admiral James Stockdale, the highest-ranking U.S. military officer held as a prisoner of war in Vietnam. The paradox: you must maintain unwavering faith that you will prevail in the end, while simultaneously confronting the most brutal facts of your current reality. The leaders who survived were not the optimists — they were the realists who never lost faith.

Thought Experiment

A disciplined imaginative exercise used to explore the consequences of principles, test the limits of theories, and reason about scenarios that cannot be physically tested. From Galileo's falling bodies to Einstein's light beam to Schrödinger's cat, thought experiments have driven some of the most important breakthroughs in science, philosophy, and strategy.

War of Attrition

A competitive strategy where victory goes to the side that can endure the longest. The objective is not to win a single decisive battle but to outlast the opponent by depleting their resources, morale, or willingness to continue. In business, attrition strategies appear in price wars, talent acquisition battles, and platform competition where survival determines the winner.