What is exponential moving average?

What it means

The weighting decays geometrically, which means every historical price still contributes something but recent bars dominate. In practice the EMA turns earlier than a simple average of the same length, at the cost of reacting to moves that turn out to be noise.

Why it matters

Popular periods — 20, 50, 200 — are popular because they are popular. There is no property of markets that privileges those numbers, and their apparent significance is partly self-fulfilling, since enough participants watch them to generate reactions.

What this changes in practice

That self-fulfilment is weaker than it used to be, and our results reflect it. Every EMA-based strategy we tested lost money on XAUUSD, including two that never fired at all because their conditions were too strict for live gold. We kept the full record public rather than quietly deleting them, because the negative result is more useful to a buyer than the positive ones.