How do hysteresis bands differ from simple thresholds?

A simple threshold says trade when the score crosses one cutoff. A hysteresis rule says the next action depends partly on the current state, so the strategy might need a higher bar to enter than to stay in, or a lower bar to exit than to re-enter.

That extra structure is useful when the score tends to oscillate near the decision boundary. Instead of flipping in and out every time noise nudges the signal, the system waits for a more meaningful move.

Near-threshold scores are often the least trustworthy place to trade aggressively. If the model or market is noisy, one cutoff can turn a barely meaningful difference into repeated entry and exit events that mostly recycle spread and fees.

Hysteresis adds memory to the policy. The strategy behaves differently depending on whether it is currently flat, long, short, or partially invested. That is why entry and exit bands are often a better description than one threshold number.

A good hysteresis rule lowers churn while preserving the moves that matter. Test whether the benefit survives worse fills, whether nearby band widths behave similarly, and whether the rule still reacts quickly enough when the edge genuinely turns.