A good decision can have a bad outcome and a bad decision a good one. Judge the decision on what was knowable when it was made.
Judge a decision by what was knowable when it was made, and keep the outcome in a separate column.
Reviewing a trade or a deal that went wrong, answering a question about a failure, and any post-mortem.
From Thinking in Bets · Annie Duke
Separate a bad year into your errors and the market's mood, name the errors specifically, and say whether the method changes.
Reviewing your own record, reading any manager's bad year, and the interview question about a mistake.
From Giverny Capital's 2025 annual letter, on a year of underperformance · François Rochon
The fair test of a decision is the information available when it was made; hindsight is a different exam.
Discussing the Lehman decision, or any post-mortem where later knowledge is contaminating the judgement.
From Inside the Meltdown · 2009
In a post-mortem, separate the direction from the pace and the explanation, and say which one failed.
Subscription pricing, crisis communication, and the behavioural question about a mistake you made.
From Netflix's third-quarter 2011 letter to shareholders · Reed Hastings and David Wells