Rate of change parameters for testable entries

Rate of change as rule inputs

Rate of change is a comparison of the current value of a price or derived series with its value a fixed number of bars earlier, shown either as a percentage or as a scaled ratio. The lookback period is the number of bars between the current reading and the earlier value.

Editorial: treat the construction as a small set of rule inputs rather than as a finished signal. The inputs are the lookback period, the plot scale, optional smoothing, and whether the trigger is a zero-line cross or an extreme band. Those inputs can then be tested as one entry procedure.

Scale, series, and a plotted condition

The reading can be plotted as a percentage with a zero equilibrium line, or as a current-to-earlier-price ratio scaled by 100 with a 100 equilibrium line. The series and the lookback length are the inputs to either form.

The series input may be any valid price, derived indicator, or custom calculation, not only a single quoted close. Rate of change can also be computed on a daily average of high, low, and close, and lookback length can be profiled across many periods for each input series.

In one illustrated bond-futures plot, readings above the reference were treated as an uptrend condition and readings below it as a downtrend condition.

A smoothed short-horizon construction

A short-horizon construction used a two-period rate of change smoothed by a four-period exponential average. The rule went long when that average rose versus the prior bar and short when it fell, so it acted on the slope of the smoothed rate of change rather than on the raw reading.

Zero-line cross and extreme-threshold entries

A zero-line cross can be written as long when rate of change crosses from below the equilibrium line to above it, and short on the opposite cross, with the lookback period left as a searchable input.

An extreme-threshold entry can be written as long when rate of change falls below a negative threshold and short when it rises above a matching positive threshold. Both the lookback period and the threshold are then available for a parameter search.

Parameter search and an out-of-sample check

A parameter search can step the lookback period from 8 through 40 in increments of 2, or step an extreme threshold from 5 through 12 in increments of 1, and then rank the resulting rule sets.

Parameters chosen on one history can be reapplied to other securities, the related industry group, and the broader market. That out-of-sample check asks whether the rule still behaves reasonably, or whether it was fitted too tightly to a single series.

Editorial: after a set is selected, try to break it on a different series rather than treating the rank order as a finished result.