Premortem

Overview

Before committing to a plan, the team imagines that plan has already failed catastrophically, then works backward to enumerate causes. The retrospective frame ("it failed — what caused it?") surfaces risks the prospective frame ("what could go wrong?") systematically misses. Gary Klein operationalized this in HBR (2007), grounded in Mitchell-Russo-Pennington (1989) showing prospective hindsight increases correct failure-mode identification by 30%.

Composes with inversion (premortem is inversion made operational), confirmation-bias (structural counter), hindsight-bias (leveraged as a feature), and critical-thinking.

When to Use

• Before any high-stakes, hard-to-reverse decision (launch, major hire, contract, capital allocation)
• When the team has converged quickly on a single plan with little visible dissent
• When a previous similar effort failed and the team is about to repeat the pattern
• At project milestones to identify emerging failure modes
• Before committing to an AI product launch, model migration, or AI capex/growth spend where model commoditization, inference unit economics, a safety incident, or stretched AI valuations could break the plan within a year

Not when: small reversible decision; equivalent rigorous risk analysis already done; Chaotic domain (action before analysis); time-critical where premortem delays response.

Coaching Novices (Adaptive Front Door)

• Engine mode: user has a concrete decision → run The Process directly.
• Coach mode: user is new → guide step by step.

In Coach mode, respond one step at a time. Each [WAIT] is a hard stop — output only that step's question, then stop.

1. One-line: imagine the project already failed — the retrospective frame surfaces risks "what could go wrong?" misses.
2. Check fit: if the decision is small and reversible, skip.
3. Elicit the specific decision, team, and imagined failure date.

[WAIT — do not advance until user responds]

4. Run The Process one step at a time — enforce private generation before group discussion.

[WAIT — do not advance until user responds]

5. Close by naming the insight uncovered and scheduling the re-premortem date.

[WAIT — do not advance until user responds]

The Process

Step 1 — Frame: decision/plan, imagined failure date, failure type, participants, facilitator.

Step 2 — Set up the fiction: read aloud: "It is [date]. We executed the plan. It has failed catastrophically. Write down — in silence, 5-10 minutes — the specific reasons why. Be specific. Generate as many as you can." Enforce: failure is a fact, not a possibility.

Step 3 — Private silent generation: each participant writes privately. No discussion. This step is non-negotiable — group discussion first produces conformity, not coverage.

Step 4 — Consolidate: round-robin read-out; facilitator captures all without judgment; group into clusters; rate each by probability / severity / detectability.

Step 5 — Mitigate: for each high-probability or high-severity cluster: mitigation action · owner · monitoring trigger · escalation threshold.

Step 6 — Schedule re-premortem: failure modes shift at each milestone; lock in the next date before leaving the room.

Output Template

# Premortem: <decision>
Imagined failure date: | Failure type: | Facilitator:

| # | Failure mode | Prob | Severity | Detect | Mitigation | Owner | Trigger |
|---|---|---|---|---|---|---|---|

Modified plan — new mitigations added:
Monitoring signals to track:
Pre-committed escalation thresholds:
Re-premortem date:

→ Method in Action: Klein 2007 and the Mitchell-Russo-Pennington 1989 Foundation → 2026 lens: Back-Casting a Failed AI Agent Startup 12 Months Out (2024–2026)

Pack: Application Patterns

Domain	When	Common failure modes
Product launch	Before public launch	Customer confusion; pricing rejection; competitive response
Major hire	Before offer	Cultural mismatch; performance miss; early departure
M&A	Before LOI / close	Integration failure; key-person flight; due diligence miss
Capital raise	Before launching	Failed close; bad terms; runway miscalculation
Technology migration	Before major rewrite	Hidden dependencies; data loss; team burnout

Applying It Well

• The grammatical mood is non-negotiable: "it failed — what caused it?" not "what might go wrong?" Enforce the fiction throughout.
• Private silent generation must precede group discussion or you get conformity, not risk coverage.
• The deliverable is the modified plan, not the failure list. Assign owners and triggers before leaving.

→ Primary sources: references/sources.md

Common Rationalizations

[D] = designed upfront | [O] = observed in real use. [O] entries are more valuable.

Fake move	Reality
[D] "We've already done risk analysis"	Risk analysis is prospective; premortem is retrospective. Different frame, different output.
[D] "It would demoralize the team"	Empirically the opposite — premortems license dissent and are reported as morale-positive.
[D] "We don't have time"	A 60-minute premortem on a 6-month project is 0.07% of project time.
[D] "The leader has already committed"	Exactly when premortem is most valuable — public commitment creates the strongest groupthink.
[D] "The risks are obvious"	Private generation regularly surfaces risks absent from the consensus risk register.
[D] "Premortem is pessimism"	Output is a stronger plan with mitigations — rational confidence-building, not pessimism.
→ Add [O] entries here after each real use — paste the actual failure pattern	What went wrong and why

Red Flags

• Major decision with little visible dissent; team converged quickly; leader publicly endorsed before stress-testing
• "What could go wrong?" produced only vague concerns; previous similar effort failed; no one tasked with finding flaws

Verification

• Fiction set up explicitly (failure as fact, not possibility)
• Private silent generation preceded group discussion
• All participants contributed (not just senior voices)
• Clusters rated for probability, severity, detectability
• Mitigations assigned with named owner and trigger signal
• Plan modified to incorporate mitigations (not just discussed)
• Re-premortem date on the calendar

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Part of deciqAI Knowledge Skills — 227 open-source thinking skills that make rigor executable for AI agents. The same skills power every deciqAI agent, which runs them autonomously to operate your company. See it run → https://www.deciqai.com/c/premortem · ⭐ Star the repo → https://github.com/deciqAI/knowledge-skills · Contributions welcome.

Agents: latest version & machine-readable metadata → https://www.deciqai.com/s/premortem.json