Write before the outcome is known
A decision journal records what you believed at the time, the evidence you used, and the alternatives you considered. This makes the reasoning easier to review without reconstructing it from memory.
Separate process from outcome
A favorable result does not prove that every assumption was sound. An unfavorable result does not by itself show that the process was careless. Compare the outcome with the uncertainty that was visible at the time.
Define a useful review trigger
A change in a key business driver or network dependency may matter more than a short-term price move. Identify the developments that would justify revisiting your research.
Use a concise template
Record the question, core observations, assumptions, alternatives, limitations, and review triggers. Keep the entry clear enough that another reader could follow the logic.
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