What it means
Expectancy is the average result per trade. In R (multiples of the amount risked): E = (win rate × average win) − (loss rate × average loss).
A positive expectancy means the method made money on average over the sample; it does not mean the next trade will.
Why traders use it
Win rate alone is misleading. A method that wins 37% of the time at +2R and loses 1R otherwise has a positive expectancy; a method that wins 80% at +0.2R and loses 1R otherwise does not.
Chart examples
Expectancy from 30 example trades
How to identify it objectively
- 1Record every trade in R (profit ÷ initial risk).
- 2Win rate = wins ÷ trades.
- 3E = win rate × average win R − loss rate × average loss R.
- 4Report it with the sample size.
Bullish use
- 1Expectancy applies to longs and shorts alike.
- 2Calculate it separately for long and short trades to see if one side carries the method.
Bearish use
- 1A negative expectancy means the rule loses on average over the sample.
- 2More trades only grow the loss.
What confirms it
- A large sample (100+ trades) with costs included.
- Similar expectancy out of sample.
What invalidates it
- Positive in-sample, negative out-of-sample.
- Costs not included.
How a hypothetical setup is built
Entry
Not an entry rule: a measurement of one.
Stop
Always record the planned stop so R can be calculated.
Target
Compare expectancy across target choices (for example 1.5R vs 2R).
A hypothetical illustration of how the concept is turned into a plan, not a recommendation. Practise it on a paper account first.
Related concepts
- Risk Management & StatisticsProfit Factor
- Risk Management & StatisticsMaximum Drawdown
- Risk Management & StatisticsPosition Sizing
- Full guide on The TradeskillJournal, Replay and Backtesting
Historical testing
The diagram uses a made-up sequence of 30 trades (11 wins of +2R, 19 losses of −1R) to show the arithmetic; it is not a backtest of any method.
Limitations: when it fails
- 30 trades is far too few to trust; the example only shows the formula.
- Expectancy can change as markets change.
- Ignoring costs overstates it.
Knowledge check
Pick an answer to see the explanation. Nothing is saved.