Premortem and Inversion

Two methods for failure-oriented ideation:

• Premortem — Gary Klein, HBR September 2007. Imagine the project has already failed catastrophically; work backwards to causes.
• Inversion — Charlie Munger via Carl Jacobi: "Tell me where I'm going to die so I'll never go there." Solve problems by figuring out how to fail and avoiding that.

Both exploit prospective hindsight (Mitchell, Russo, Pennington 1989): people generate more concrete reasons for an event when imagining it has already happened than when imagining it might.

When to use

Premortem

• Choosing between project options
• Pressure-testing a near-term decision
• Late-stage planning for a long-horizon project
• Group decisions with social pressure suppressing dissent

Inversion

• Strategic direction choice (easier to identify clear failures than clear successes)
• Personal life decisions (career, marriage, investments, health)
• Identifying hidden anti-patterns in your own behavior
• Designing systems against adversaries (security, abuse-prevention)

Don't use when

• Early generative phase — corrosive to fragile ideas
• You can't act on the failure modes (anxiety, not planning)
• Group lacks psychological safety to articulate fears about the leader's project
• Decisions that need urgency (premortem takes 60–90 minutes done well)

Premortem procedure

1. State the project as if it's complete and failed. "It is [date 6 months from now]. We launched. The result was a complete disaster."
2. Generate failure narratives independently. Each member writes a paragraph describing what happened, in concrete terms. Independence is essential — group brainstorming surfaces socially safe concerns; independent writing surfaces uncomfortable ones.
3. Round-robin failure causes. Each shares one cause; no comment. Continue until exhausted.
4. Cluster and assess. Group similar; estimate probability and severity.
5. Generate mitigations for the top 3. Update the plan.
6. Re-run periodically. Failures unlikely at planning time may have become likely.

Inversion procedure

1. State the goal: "I want to [original goal]."
2. Invert: "How would I guarantee the opposite?"
3. List 5–10 things that would guarantee the inverted goal. Be specific.
4. Self-check: which am I accidentally doing or could drift into?
5. Avoid those; return to original goal.

Worked inversion example

Goal: I want my open-source project to attract sustained contributors.

Inversion: how would I guarantee that no one ever contributes?

1. Have no CONTRIBUTING.md or unclear norms.
2. Reject PRs without explanation, slowly.
3. Make the build hard to reproduce locally.
4. Use a tone in issue threads that makes contributors feel stupid.
5. Use a license requiring CLAs new contributors won't sign.
6. Take 6+ months to merge anything.
7. Reply to issues with one-word answers.
8. Have only the founders in the maintainer org.

Self-check: which am I doing? Honest answer surfaces 2–3 of these. Those are the highest-leverage fixes.

Anti-slop notes

• Premortem slop = generic risk lists ("execution risk", "market risk"). Real premortem narrative says specifically what went wrong.
• Inversion slop = "do the opposite of successful people" — that's contrarianism. Real inversion identifies specific failure-guaranteeing actions in your situation.
• Don't generate fake fears. If there are no real concerns, the premortem is short.
• Don't use these to talk users out of pursuing things they should pursue. Premortem and inversion are pressure tests, not vetoes.

Source: Klein, "Performing a Project Premortem", HBR Sept 2007. Munger, Poor Charlie's Almanack (PCA, 2005).