Base rate

The base rate is the underlying frequency of an event in a population. Because manipulation is rare relative to total order flow, ignoring the base rate makes any detection statistic look far more damning than it is.

compliance and practice · updated 2026-09-08

See also

• False positive — A false positive is a surveillance alert that turns out to be innocent activity. Manipulation detection operates at very low base …
• Surveillance — Surveillance, in a market context, is the automated monitoring of order and trade data for patterns that suggest abuse. Exchanges,…

Terms that refer here

Detection rate · False positive

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