Biometric security devices are generally considered to be highly accurate. The accuracy of a biometric system is usually measured in terms of the false acceptance rate (FAR) and the false rejection rate (FRR). The FAR is the likelihood that an unauthorized user will be mistakenly granted access, while the FRR is the likelihood that an authorized user will be denied access. A good biometric system will have a low FAR and a low FRR.
The accuracy of biometric security items can be affected by a number of factors, such as the quality of the sensor used to capture biometric data, the cleanliness of the sensor, and the physical condition of the user. For example, a fingerprint reader may have trouble recognizing a fingerprint that is dirty or damaged. However, with proper maintenance and calibration, biometric security products can provide a high level of accuracy and safety.