What is False Accept Rate (FAR)?
False Accept Rate (FAR) is the rate at which a system erroneously accepts an impostor. For 1: 1 verification it means an unauthorized person is granted access; for 1:N searching it means a wrong identity is returned above threshold. Lowering FAR reduces the risk of fraud, but if you push it too low, legitimate users will be locked out.
Select thresholds contextually: for high-risk actions, err on the side of low FARs and friction; for casual logins, balance FAR against user experience and False Reject Rate. Monitor FAR with DET/ROC curves, don’t use a single number. As attack pressure from deepfakes intensifies, fortify with liveness and make sure your references were derived from strong identity verification.
