Decision Journal

A decision journal records a decision at the moment it is made - the decision, the rationale, the predicted outcome, an explicit confidence level, and the assumptions it rests on - so it can be reviewed later against what actually happened. The load-bearing move is timing: the prediction is fixed in place before the outcome is known, while the reasoning and the felt confidence are still uncontaminated by the result. That contemporaneous record is the one reliable defense against hindsight bias ("I knew it all along"), it separates decision quality from outcome quality, and it supplies the recorded-prediction half of a calibration loop. The output is a structured decision journal entry, not prose, designed to be reopened and scored later.

When to Use

• At the point of committing to a consequential, genuinely uncertain decision: a launch, hire, investment, vendor choice, bet, or strategic direction.
• When you can still state an honest prediction, confidence level, and set of assumptions before the outcome is known.
• When you intend to review the decision later against reality - it pairs with an after-action review (record now, review later).
• When you want to build calibration over many decisions, not judge a single one.

When NOT to Use

• To review a decision after the outcome is already known. That is an after-action review (think-after-action-review); writing a "journal entry" after the result back-fits the prediction, the exact distortion this method exists to prevent.
• For trivial or fully reversible (two-way-door) decisions. The capture overhead is not worth it for a cheaply undone choice with no real uncertainty.
• When no expectation can be honestly stated. If there is no genuine prediction, confidence, or assumption to record, the entry is theater.
• To surface only the conditions that must hold for a choice to be right. That is think-what-would-have-to-be-true; the journal captures the whole decision plus a predicted outcome and confidence for calibration.
• As a substitute for actually reviewing entries later. A journal nobody revisits delivers no calibration; if there is no intent to review, skip it.