Judge decisions by process quality, not by whether they happened to work out

Duke's foundational argument is that outcomes are a noisy, unreliable signal for judging whether a decision was actually good, because luck and uncontrollable external factors influence results as much as, or more than, the quality of reasoning behind a choice. A well-reasoned bet can lose due to bad luck, and a poorly reasoned one can win due to good luck, yet people instinctively praise winners and blame losers as if the outcome directly reflected decision quality.

She argues this outcome-fixation actively damages learning, since it teaches people the wrong lessons — reinforcing lucky recklessness and punishing well-calibrated caution that simply ran into bad variance. Judging the decision process instead, independent of how things turned out, is the only way to genuinely improve over repeated decisions rather than just chasing whatever happened to work last time.

Takeaway: after any decision, ask whether the reasoning was sound given the information available at the time — the actual outcome is a separate, much noisier question.