Scenario Analysis

Testing decisions against several plausible futures instead of one forecast.

Also known as: scenario analysis, what-if analysis, scenario planning

Scenario analysis replaces one forecast with several: a base case, an upside and a downside — each a coherent story about the future with numbers attached. Instead of betting the plan on a single line, the team sees what each future demands and which decisions survive all of them.

base:     growth continues → hire 6, spend X
upside:   viral loop catches → need capacity + support (trigger: waitlist > N)
downside: churn persists → freeze hiring, cut discretionary (trigger: logo churn > Y%)

Good scenarios differ in kind, not just by ±10%. Vary the drivers that actually branch the future — a key deal closing, a regulation landing, a competitor move — and attach a trigger to each so the team knows which future arrived and what to do. A scenario without a trigger and an action is fiction.

The classic mistakes:

Three versions of the same story. Base/upside/downside at ±10% share every assumption that matters. Scenarios must disagree about the world, not just the growth rate.
Too many scenarios. Seven futures paralyse; nobody plans for seven. Three or four, sharply distinct.
Probabilities nobody believes. False precision (“23% likely”) invites arguments about the number instead of the plan. Rank likelihood roughly or leave it out; the value is the prepared response.
Built once, never revisited. Scenarios rot as the world moves. Revisit when a trigger fires or quarterly, whichever comes first.
Analysis as cover for indecision. Scenarios inform a choice; they are not a substitute for making one. End with the decision each future implies.

When to use it: high-uncertainty, high-stakes calls — annual plans, capacity bets, pricing changes — where a single forecast would be a lie told precisely. For stable operations, a forecast with intervals is enough.