Win rate feels intuitive, but expectancy determines whether your edge survives over many trades. High win rate with poor payoff can still fail.
Expectancy is your true edge metric
Expectancy in R estimates average trade outcome after accounting for both winners and losers.
A strategy with lower win rate can outperform if average wins are materially larger than average losses.
Why win rate alone misleads
Many traders optimize for being right often, then take oversized losses when wrong.
This creates fragile profiles that look good in short samples but degrade under stress.
Use expectancy to prioritize upgrades
When expectancy is weak, improve one variable at a time: entry quality, exit quality, or risk consistency.
Randomly changing all parameters at once hides the true source of improvement.