What is False Rejection Rate Type I?

Understanding False Rejection Rate Type I

This is failure to recognize a legitimate user. In biometric and authentication systems, the False Rejection Rate FRR is the probability that the system incorrectly rejects an authorized user. It represents a usability error where a legitimate user is denied access despite being entitled to it. FRR is a key usability metric addressed in standards like ISO IEC 19795 for biometric system evaluation. Organizations tune authentication systems by balancing FRR against False Acceptance Rate FAR based on usability requirements, with user-friendly applications prioritizing lower FRR. For example, a smartphone fingerprint authentication might be configured with a relatively low FRR to ensure legitimate users can conveniently access their device, accepting a slightly higher FAR as a tradeoff. Related terms: Biometric authentication, False Acceptance Rate FAR, Crossover Error Rate CER, Authentication accuracy, Receiver Operating Characteristic ROC, Security-usability tradeoff.