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TRAP #554 ·VOL V The Toolkit · Systems Thinking, Mental Models & Decision FrameworksLEXICON ENTRY

The Premortem

Discovered by Gary Klein, 1998

Imagine the plan already failed. Now work out why.
Category: ToolEvidence: ReplicatedUniversality: HighTier 1Type: Mechanismⓘ what these mean

This is a Lexicon entry: the mechanism, when it shows up, and the countermeasure. The full correction, with real-world cases and the audit prompt, hasn't been written yet.

Definition

A planning technique in which a team imagines, before committing, that the project has already failed, then works backwards to explain why. Treating the failure as a fact rather than a possibility licenses people to voice doubts that optimism and group pressure would otherwise suppress. Gary Klein developed it as a structured counter to overconfidence and planning bias. It is the prospective mirror of a postmortem.

Failure mode

Not a failure; a decision practice. Without explicit premortem, risks are underestimated. Planning bias produces overconfident forecasts.

Countermeasure

Before committing, assume the project has already failed. Generate the most plausible explanations for the failure. Use the explanations to adjust the plan before committing, not after.

Get the pre-decision checklist →

Related traps

Also connected in the map6 more, locked

Credit & first seen

DiscoveredKlein, G. (1998). Sources of Power: How People Make Decisions. MIT Press source ↗

Also revealed

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This entry has the mechanism and countermeasure. The full write-up - real cases, sources, the audit prompt - comes later.

Entry #554 of 631 in The Lexicon · see the full Lexicon