Run a Pre-Mortem Before Deciding
Added 2026-11-01
Assume the decision already failed, work backwards to causes and early signals.
I am weighing a decision (described below). Run a pre-mortem: 1) assume it clearly failed a year from now, write the three most likely causes; 2) give each an early signal observable now; 3) give each a low-cost preventive action; 4) judge which cause would be most fatal and least reversible; 5) end with one line: do it now, or wait for a specific signal.
Site original
Chinese original
How to use
先想失败，比先想成功更能筛掉坏决定。
Try tweaking it
- Ask what evidence would overturn the judgement.
- Have it argue both sides with three reasons each.
What you should get
- A decision table: assumptions, evidence, counter-evidence
- A next action with an observable signal
Common mistakes
- Asking only "should I?" and getting equally valid answers both ways.
- Never asking for counter-examples, so you only hear support.
How to check the output
- It states what evidence would overturn the conclusion.
- Both sides are argued, with assumptions marked as such.
Where it works
- Good for: splitting a decision into assumptions, evidence and counter-cases, leaving the call to you.
- Watch out: ask what evidence would overturn the judgement, or you will only hear supporting reasons.