Expectancy
Expectancy is the average result a trader can expect from a single trade, given a strategy's historical win rate and average win/loss size. It's calculated as (win rate × average win) minus (loss rate × average loss). A positive expectancy means the strategy makes money on average per trade over time; a negative expectancy means it loses money on average, no matter how good any individual trade felt.
Unlike win rate or profit factor alone, expectancy is a per-trade figure — it answers 'what do I expect to make (or lose) on the next trade, on average,' which is the number that actually compounds into an account's results over many trades.
Why it matters
Expectancy is where win rate and average win/loss size come together into a single, decision-useful number — it's the metric that resolves the ambiguity that win rate and profit factor leave open on their own. A strategy with a mediocre win rate can still have strong positive expectancy if its winners are large relative to its losers, and a strategy with an impressive win rate can have weak or negative expectancy if its rare losses are large enough to erase many small wins.
The same sample-size caveat applies here as with win rate and profit factor: expectancy calculated from a handful of trades is a noisy estimate, not a reliable edge, and it can shift meaningfully as more trades are added to the sample.
In MimikTrader
Expectancy is one of the KPIs on the Pro plan analytics dashboard, computed from a connected account's actual broker fills.
Example
Example: a strategy wins 40% of trades for an average of $250 and loses 60% of trades for an average of $120. Expectancy = (0.40 × $250) − (0.60 × $120) = $100 − $72 = $28 per trade. On average, each trade this strategy takes is worth about $28 — a small positive edge that only becomes meaningful over a large enough sample of trades.
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