Scaling out at 1R: what it does to expectancy, worked through

[FXS London Scalper]

Taking half off at 1R and running the rest feels safe. Whether it helps depends on how often trades go past 1R, which is simple arithmetic.

A worked example with hypothetical numbers: full target at 2R, stop at 1R.

• Without scaling: 40% of trades hit 2R, 60% lose 1R. Expectancy: 0.4 × 2 − 0.6 × 1 = +0.2R.
• With half off at 1R, rest to 2R or breakeven: suppose 55% reach 1R and 40% of all trades go on to 2R. Expectancy: 0.4 × 1.5 + 0.15 × 0.5 − 0.45 × 1 = +0.225R.

In this example scaling slightly improves expectancy and smooths results. With different numbers, for example if the typical trade reaching 1R carries on to 2R anyway, scaling reduces it.

Costs matter: two exits mean more slippage, and on a tight scalp that can tip the balance.

How to decide with your own data: from your journal, find what share of trades reached 1R, and of those, what share reached the full target. Plug in your numbers.

Do you scale out, and did you check the numbers?