The bias that inverts your ratio
The effect is arithmetic rather than emotional: closing winners at +0.5R while holding losers to −2R converts a system designed at 1:2 into one executed at 1:0.25.
Hence a paradox that confuses many traders: your win rate may rise because you close winners quickly, while expectancy collapses because the losses are larger. Watching win rate alone shows an illusory improvement while the account bleeds — precisely the case that makes win rate dangerous on its own.
Measuring a bias you cannot feel
Behavioural biases are not fixed by general advice, because in the moment they do not feel like biases — they feel like sound decisions. The only practical approach is for each bias to have a measurable signature in your trade record.
So each page here gives the numerical marker that exposes the bias rather than asking you to "be disciplined". You do not need to be told to have discipline; you need to know whether you currently lack it.
A worked example
A system designed at 1:2 whose win rate is 40% returns +0.20R. Apply loss aversion: winners closed at +1R instead of +2R, losers held to −1.5R instead of −1R.
Expectancy becomes (0.40 × 1) − (0.60 × 1.5) = −0.50R per trade. Same system, same analysis, same win rate — and the result flipped from profitable to losing by a wide margin, because execution alone changed. That is the gap between the written system and the executed one, and it appears only when you measure the realised ratio from the record.
Common mistakes with this term
- Measuring improvement by win rate alone, which rises precisely as this bias worsens.
- Moving the stop away to avoid realising a loss, turning a 1R loss into 2R or more.
- Never measuring the realised ratio from the record and trusting the planned one instead.