Updated: 2026-03-06
How to Review Your Trades: The Evidence-Based Method
Barber and Odean's 2000 analysis of 66,465 brokerage accounts (Journal of Finance) found that the most active traders underperformed passive market returns by 6.5% per year on average. The study is widely cited as evidence against active trading — but the more precise lesson is about review quality. The traders in the underperforming quartile did not lack information. They lacked a systematic method for turning their trade history into behavioral corrections. The Dalbar Quantitative Analysis of Investor Behavior (2023) shows that the average equity investor earned 3.7% annually over twenty years while the S&P 500 returned 9.65% — a gap explained almost entirely by behavioral decision-making errors, not strategy selection. Trade review done well is the single highest-leverage activity available to an active trader. Most traders do it badly, or not at all. This guide covers what evidence-based review actually looks like and why most traditional approaches produce no lasting behavior change.
