What Is a Rolling Backtest

A rolling backtest in five lines

A rolling backtest is the same rule on the same tape, scored in windows that move along it rather than once for the whole. The reason is that a single total hides the weeks, and the weeks are where a rule is lived. It shows the streaks, the worst stretch, and whether the total came from everywhere or from one place. The window can be a week, a month or a hundred trades, the same size all the way along. In the example, the plain 10:00 to 18:00 rule on the euro scored week by week through 27 weeks of 2026 made 150.3 pips in all, where a pip is the fourth decimal place of the price, with 15 weeks up and 12 down.

A surveyor's wheel

Picture a surveyor's wheel, the kind pushed along a road that clicks once a metre. The counter on the handle shows the total at the end; the clicks along the ground, one per week, are the result. A wheel that only shows the counter has measured the road, and a wheel that shows every click has walked it, which is the difference between a backtest with one total and a rolling one. The clicks are where the long runs of nothing and the sudden drops are, and a trader lives in the clicks, not in the counter.

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