Repainting indicators and the history that never existed
Posted: Sat Oct 31, 2026 6:57 pm
Some indicators change their past values as new bars arrive. Zigzag types, certain swing detectors, and fractals look flawless on the chart because the historical display has been revised in hindsight. The signals that appear in the past were not visible in real time.
Scalpers who build rules on repainting tools experience a nasty gap between visual backtesting and live performance. The chart shows a clean turn at every swing, but in real time, the signal appears late or disappears.
To identify repainting, record the indicator's value in real time for several hours and compare it with the same bars afterward. Differences confirm the problem.
Also be wary of indicators that use the current bar's high or low before it is complete. Their values shift until the bar closes.
If a tool is essential, use a version that confirms signals only after a defined delay, and measure the performance with that delay included.
Honest testing means using only the information that was available at the time of the decision.
How is an indicator checked for repainting before it enters a strategy?
Scalpers who build rules on repainting tools experience a nasty gap between visual backtesting and live performance. The chart shows a clean turn at every swing, but in real time, the signal appears late or disappears.
To identify repainting, record the indicator's value in real time for several hours and compare it with the same bars afterward. Differences confirm the problem.
Also be wary of indicators that use the current bar's high or low before it is complete. Their values shift until the bar closes.
If a tool is essential, use a version that confirms signals only after a defined delay, and measure the performance with that delay included.
Honest testing means using only the information that was available at the time of the decision.
How is an indicator checked for repainting before it enters a strategy?