Investing term

What is Decision journal?

A pre-trade written record of your thesis, sizing, and what would change your mind.

A decision journal is a written record made before you trade, capturing your reasoning, how big the position is, and what would prove you wrong. Its power comes later: when you review it, you see your actual thinking rather than the rewritten memory your mind invents after the outcome. It's the single best tool for learning from your own decisions honestly.

For example

Before buying, you write "I expect 20% upside on a product launch; I'm wrong if sales stall" — months later that note tells you if you were right for the right reasons.

Decision journal is taught hands-on in Stage 13 — Active Investing: Should You Even Bother?.

See the lesson →

Related terms

Active investingPicking individual stocks (or actively-managed funds) instead of just buying the index.CatalystThe event or condition that will close the valuation gap — and an estimated timeline.Circle of competenceThe set of industries, business models, and types of companies you actually understand well enough to evaluate.ConvictionHow strong your evidence is for a thesis — and therefore how much capital it earns.
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