Learn in the textbookBiometric Authentication and Authentication Accuracy Metrics
DefinitionThe false acceptance rate (他人受入率) is the rate at which someone other than the registered user is wrongly accepted as that user.
ExplanationWhen this rate is high, an impostor can pass by posing as the genuine user, which undermines security. Because biometric authentication decides by how closely the captured features match, there remains a chance of mistaking someone with very similar features for the real user.
AnalogyIt is the share of outsiders let in by a gatekeeper who has set the pass mark too low.
Memory hookIn the Japanese name 他人受入率, the subject is 他人 (someone else): read it as the rate at which an impostor gets accepted.