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 proposed solution? What is the expected return? What are the risks? What happens if we do nothing? Every organisation makes resource allocation decisions. The business case is the mechanism that forces those decisions to be explicit rather than political. Without one, capital flows to whoever argues loudest, whoever has the most seniority, or whoever cornered the CEO at lunch. With one, capital flows — at least theoretically — to the initiative whose logic survives scrutiny.

The format varies. McKinsey formalised the structured business case in the 1960s as a consulting deliverable: situation, complication, resolution, supported by quantitative analysis of costs, benefits, and risks. The British government's Green Book methodology requires a five-case model — strategic, economic, commercial, financial, and management — for any public spending above a threshold. Amazon uses six-page narrative memos that read like arguments, not slide decks. The surface differs. The underlying discipline is identical: make the assumptions explicit, quantify what can be quantified, and force the decision-maker to confront the trade-offs rather than hiding them in a financial model's nested tabs.

The most dangerous business cases are the ones that look rigorous but aren't. A thirty-page document with a discounted cash flow model projecting revenue to 2035, complete with three scenarios and a sensitivity analysis, can be pure fiction if the assumptions driving the model are wrong. Revenue projections extrapolated from a single quarter. Market size pulled from a Gartner report without questioning whether the company can address any of it. Cost estimates that omit integration complexity, organisational resistance, or regulatory risk. The spreadsheet creates the illusion of precision. The assumptions behind it determine whether the precision means anything. Jeff Bezos understood this when he banned PowerPoint at Amazon and required narrative memos instead. A narrative forces the author to connect assumptions to conclusions in prose — which makes logical gaps visible in ways that bullet points and charts never do.

The best business cases do something counterintuitive: they spend more time on the "do nothing" scenario and the critical assumptions than on the projected upside. The projected upside is the easy part — anyone can build a model showing a positive return if they control the inputs. The hard part is identifying the two or three assumptions that, if wrong, would invalidate the entire thesis. A business case for entering the Chinese market that doesn't identify "regulatory approval within 18 months" as a critical assumption isn't a business case — it's a sales pitch. A business case for acquiring a competitor that doesn't model the integration costs realistically isn't an analysis — it's advocacy. The discipline of the business case is intellectual honesty under institutional pressure to be optimistic.

The "do nothing" scenario is where most business cases fail hardest. Organisations treat inaction as costless — the default state against which the proposed initiative looks attractive by comparison. But inaction has costs. Market share erodes. Competitors advance. Technical debt compounds. Key employees leave. The business case that models the cost of inaction alongside the cost of action gives the decision-maker a genuine comparison rather than a choice between "invest" and "nothing happens." The strongest cases make inaction feel as risky as action — because it usually is.