DEFINITION · Updated June 2026

Sample size

The number of trades or predictions in your record. Larger samples make a real edge (or leak) statistically detectable; small samples are dominated by variance and prove almost nothing.

The single most underrated concept in trading. A great-looking month is usually too small a sample to mean anything. How many trades you need depends on your edge and prices, our trades-to-prove-edge calculator turns that into a number.

GO DEEPER
Trades-to-prove-edge calculator
More terms
Event contractDesignated Contract Market (DCM)Section 1256 contract60/40 ruleWash sale ruleMark-to-marketForm 6781Form W-2GFull glossary →