There are three main performance metrics when evaluating biometric technologies. They are false match rates (FMR), false non-match rates (FNMR), and failure to enroll rates (FTER). A false match means that the technology has incorrectly matched an identity to a presented biometric, and the FMR is the probability of the incorrect matches. Incorrect matches in a positive identification system mean that unauthorized people could gain access to resources or places to which they are not allowed. False nonmatches happen when the technology rejects a valid presented biometric. False nonmatches could mean that an authorized person is denied access to a place, where he or she is, in actuality, permitted. The FTER is the probability that an individual will not be able to be entered into the database. These failures can occur for different reasons including the inability to capture a sufficiently distinct sample or from system designs that inhibit consistent readings.