A written log in which a decision-maker records — before the outcome is known — the question being decided, the options considered, the reasoning behind the chosen path, the predicted outcome, and the confidence level. Popularized by Daniel Kahneman, Annie Duke, and Shane Parrish, decision journals are the highest-leverage tool for improving decision quality over time because they neutralize hindsight bias.
Reviewing the journal six or twelve months later separates good decisions from lucky ones and bad decisions from unlucky ones.