Also called Average directional index

ADX

Measures how strong a trend is without saying which way it points. Low readings mean a market going sideways, where trend-following strategies bleed.

Updated 2026-09-03

The average directional index measures how strong a trend is without saying which way it points. It runs from 0 upward, and readings below about 20 mean a market going sideways.

That directional agnosticism is the point. ADX at 40 means a powerful trend, and it is equally consistent with a powerful rally and a collapse. It answers one question only: is there a trend here worth trading, or is price just oscillating.

Why it belongs in a trend strategy

Because trend-following strategies bleed in flat markets. A crossover system in a sideways range generates entry after entry, each one reversing shortly after, and every one of them costs the spread. A low ADX is the cleanest available warning that the conditions a trend strategy needs are absent, so it is used as a gate on entries rather than as a signal in itself. It feeds directly into signal confidence.

ADX is slow, because it is a smoothed measure of a smoothed measure. It confirms a trend well after it began and stays elevated well after it ended. Treat it as a description of conditions rather than as a timing tool.

See also

  • EMA — An average of recent prices that weights the latest days most heavily, so it turns faster than a simple average. A fast one crossing above a slow one is the classic trend signal.
  • Signal confidence — The weighted entry score a bar must clear before the strategy opens a trade, built from trend and momentum agreement. It says nothing about whether a stock is cheap.

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Educational content, not investment advice. Angie explains how a valuation is built so you can judge it yourself. What you do with that is your call.

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