Glossary / Trend & momentum
Rate of change
Also called: ROC · price rate of change
Rate of change is the percentage difference between the current price and the price a fixed number of sessions ago. It is the most direct measurement of how quickly price has moved, with no smoothing in between.
How it is measured
How is rate of change measured?
Take the current price, subtract the price at the start of the lookback window, and divide by that starting price. The lookback length is the whole design decision: a short window reacts fast and reverses often, a long window is steadier but reaches a genuine turn late.
Why it matters
Why does rate of change matter to a swing trader?
Almost every momentum study reduces to a rate of change with extra processing on top, so understanding the raw version makes the derived ones legible. For a swing trader the practical caution is that the measurement is a two-point comparison — it reads only the start and the end of the window, so a sharp move that fully reversed inside the window is invisible to it.
In Tapeline
Does Tapeline use rate of change?
This is the shape of the Momentum factor. Tapeline's Momentum sub-score reads a short-horizon return alongside a momentum-quality input, and the composite weights Momentum least of the six factors because short-horizon rate of change reverses often.
Tapeline publishes the six factor names and the ordering of their weights. The numeric weights, the scoring equation and the band edges are not published.
Related
See this in the product
What the Momentum factor measures · The Momentum factor · Full methodology
Related terms
Back to the full glossary.
General information about market vocabulary, written to be descriptive rather than prescriptive. Not investment advice — see the risk disclosure.