What is average directional index?

What it means

ADX answers only one question — is there a trend — and deliberately says nothing about which way. That narrowness is what makes it useful as a gate rather than a signal: it tells you which family of strategy is appropriate, not what to do.

Why it matters

It is also slow. ADX is derived from smoothed directional movement, so it confirms a trend well after the trend began and stays elevated after it has ended. Treating a rising ADX as a reason to enter is usually late; treating a low ADX as a reason not to take trend trades is usually right.

What this changes in practice

Our engine uses it exactly that way. Trend strategies are gated behind ADX of at least 18, EMA-TREND required at least 25, and the mean-reversion and sweep strategies run regardless of the reading. That asymmetry is the point — a single number decides which half of the strategy set is even eligible to compete.