Two units for scoring trades: percentage of account, which mixes in sizing decisions, and R, which isolates the quality of the trade.
A trade that makes 1.5% of the account tells you about size and result together. The same trade at plus 2R tells you it returned twice its planned risk, regardless of how big the position was.
Use R to judge the strategy and percentages to judge the account. If R expectancy is stable at plus 0.35 while percentage returns fall, the strategy is fine and sizing has drifted - see sizing-drift. If R expectancy is falling, the edge is degrading and no amount of sizing will fix it. Separating the two is the fastest diagnostic in a trading-journal.
The conversion is direct: percent return ≈ R multiple x risk-per-trade percentage. At 0.8% risk per trade, a plus 3R trade is plus 2.4% of the account, and an expectancy of plus 0.3R per trade over 200 trades a year is roughly plus 48% before compounding and costs - a reminder that expectancy per trade is only half the equation. The other half is trade-frequency.
Original diagrams for the ideas on this page. Illustrative, not real market data.
Expectancy: the average trade. Forty trades sorted by outcome: 24 small losses and 16 larger wins. Weighting each side by how often it happens gives the average result per trade, marked here by the dashed line at +$120.Working out a position size. Three numbers decide how big a trade is: the account, the share of it put at risk, and the distance from entry to stop. One percent of $25,000 is a $250 budget, and a $0.50 stop divides into that 500 times.
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