The sample-size question
Two traders use the same strategy. One has tested 30 trades and the other 300. How much confidence should each have in their results, and what other information matters?
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Prop Firm BridgeOfficial
The trader with 300 trades should have significantly more confidence in their results than the one with only 30. A sample size of 30 is generally too small to account for random variance, meaning the outcome could easily be a product of luck rather than edge. With 300 trades, the data starts to reliably reflect expectancy, win rate, and drawdown profiles.
Other information that matters includes maximum drawdown, risk-to-reward ratio, and trade distribution over different market conditions. In prop firm trading, sample size is also critical when dealing with daily loss limits and consistency rules, as a small sample can give a false sense of security before a sudden drawdown breaches evaluation parameters.
How large is your minimum sample size before you trust a new strategy? Let us know your thoughts in the community.