Sample Size & Statistical Confidence
Know when results are meaningful and when they are just noise.
A small sample can be misleading. Ten trades can make a weak strategy look excellent or a strong strategy look broken. Professional review requires enough trades to estimate win rate, average win, average loss, drawdown, and execution quality with more confidence.
Sample size does not need to be perfect before you learn from it, but the conclusion should match the evidence. After twenty trades, you may notice obvious mistakes or poor timing. After fifty to one hundred trades, performance patterns become more useful. Larger samples are better when the setup occurs frequently and conditions are stable.
Separate strategy results from trader behavior. A playbook may have positive expectancy when followed, but negative results when you chase entries, move stops, or skip targets. Track rule-following alongside P&L so you know whether the edge or the execution needs work.