“Our real target was the microcosms of our decision makers: unless we influenced the mental image, the picture of reality held by critical decision makers, our scenarios would be like water on a stone.”Pierre Wack (Harvard Business Review) · Scenarios: Uncharted Waters Ahead · 1985 · Pierre Wack, «Scenarios: Uncharted Waters Ahead», Harvard Business Review, septembrie 1985, secțiunea despre «microcosmosul» decidentului
A good scenario does not guess the future; it changes the map in the decision-maker's head.
Wack headed the business environment division of the Royal Dutch/Shell Group's planning department, and his article opens with an uncomfortable observation: forecasts are dangerous precisely because they are usually right. They assume tomorrow will look like today and fail exactly when everything changes. The answer is not a better forecast but accepting uncertainty as a structural feature of the environment. The method separates two things: predetermined elements — what has already happened but whose consequences have not yet unfolded, like monsoon rains in the upper Ganges basin that will certainly show downstream — and critical uncertainties. The former are treated as facts; scenarios are built only on the latter. Today's practice has standardised the form. You pick, by consensus, the two most critical and uncertain forces, turn them into axes, and the four quadrants of the 2×2 matrix become four plausible worlds; the 2009 Tradecraft Primer describes exactly this step. For each world you write the indicators that would show it is becoming reality. The trap, in Wack's terms: first-generation scenarios that merely combine obvious uncertainties, such as one oil price or another, do not help decisions. A good scenario changes the decision-maker's mental model; otherwise it is water on a stone.
The next step: a good scenario does not end on paper. It must be rehearsed in the mind, like a dress rehearsal. The decision maker imagines living inside each world and notices where his usual model cracks. The valuable signal is that discomfort: when a plausible world feels absurd, that is exactly where your blind spot sits. A manager picturing his stores closed for a week discovers he has no plan for payments or supplies. That discovery is the point, not the story itself. The practical question becomes: what, in each scenario, would force you to drop a belief you now hold as certain?
Passage 2: Wack insists on a distinction most people skip: not everything uncertain deserves a scenario. Part of the future is already written; only its consequences haven't shown up yet. Children born fifteen years ago will, whatever happens, be teenagers in a few years. A company's decision today to close a factory will hit tomorrow's supply chain regardless of crises. That is the predetermined part: you treat it as fact, not as question. The scenario is built only on what remains genuinely open. The usual mistake is the reverse: doubting settled things while ignoring what nobody can know. A mayor planning schools should treat birth rates as known fact and only internal migration as uncertainty. The next question: how do you actually recognize what is already determined and what isn't?
Why it matters Shell's scenarios did not guess the timing of the 1973 oil crisis, but they prepared management for its possibility — something a single forecast could not do.