False Acceptance Rate (FAR)

False Acceptance Rate (FAR) is a measure used in security systems to indicate how often an unauthorized person is mistakenly allowed access. It represents the percentage of times the system incorrectly recognizes an impostor as an authorized user. A lower FAR means the system is more accurate at blocking unauthorized access, enhancing security. For example, if a fingerprint scanner has a FAR of 0.1%, it incorrectly grants access to an impostor 0.1% of the time. Balancing FAR with other metrics ensures the system is both secure and user-friendly.