Designing a Decision Journal — The Investor's Most Powerful Self-Improvement Tool

You will never improve at investing by remembering your best decisions. Memory is not an honest recorder. You improve by accurately documenting and reviewing all your decisions — especially the ones you would rather forget.

Why This Matters

Human memory is self-serving and systematically unreliable. We remember our successful calls with clarity and attribute them to skill. We misremember our failures in ways that protect our self-image — the information was unavailable, the event was unforeseeable, or we "almost" did something different. A decision journal breaks this cycle by creating a contemporaneous, verbatim record of your reasoning at the moment of decision — before the outcome is known. This record is the only version that can reveal actual biases.