What is Bollinger Bands?

What it means

Because the bands are volatility-scaled, they adapt automatically to conditions rather than using a fixed distance. A touch of the upper band means price is statistically extended relative to its own recent behaviour, not relative to any absolute level.

Why it matters

The two common uses point in opposite directions. Mean-reversion traders fade band touches; breakout traders treat a band expansion after a squeeze as the start of a move. Both work in the right regime and both fail in the other, which is precisely the regime problem that makes range versus trend classification worth solving.

What this changes in practice

Our BB-REV strategy fired zero times in twenty days of live trading, having looked reasonable in replay. It was cut for redundancy as much as performance — RANGE-REV already covered the same edge, and duplicated coverage in a tournament means two strategies competing to take the same trade.