Audit plans for scenario inflation

Before committing to a plan that depends on multiple things going right, count the dependencies.

Why it works

Plans are coherent stories, and the conjunction fallacy inflates the apparent probability of compound plans: "we will recruit effectively AND launch on time AND customers will respond." Each "and" is a multiplication of probabilities; a plan with five 80%-likely steps has only a 33% chance of complete success even if each step is quite likely individually. Auditing for hidden conjunctions turns an appealing narrative into an honest probability landscape and often motivates simplifying the plan.

How to do it

1. List every assumption your plan depends on succeeding.
2. Assign a rough probability to each assumption independently.
3. Multiply the probabilities (or simply count the number of "and" dependencies) to get a rough joint probability.
4. Identify which assumption, if wrong, is most damaging, and address that first.

Evidence

The multiplication rule for independent events is mathematically established; its application to planning underestimates risk in a way consistent with the planning fallacy and conjunction fallacy literatures. (mechanistic)

Real plan steps are rarely truly independent, and dependencies can cut both ways; this audit is a corrective heuristic, not a precise probability calculation.

Common mistake

Counting only the explicit assumptions and missing the implicit ones — most plans depend on more conditions than they name, so the audit should actively search for unstated dependencies.