Tactical Information Systems
Biometric Identification Software

Accuracy & Errors

Biometrics 101

The lower you set one type of error, the higher the other type becomes.

The lower you set one type of error, the higher the other type becomes.

In biometrics, one of the first questions that comes up is about accuracy. It's a complicated issue because a biometric match is never a sure thing - it is a matter of probability. When a phone owner unlocks their phone with a fingerprint, the phone is not 100% sure that the fingerprints match. And this a problem because we want important things to be 100% true. It's just not possible in biometrics (blame math).

There are two types of errors a biometric system can make. A system can erroneously match someone it shouldn’t. This type of error is called a false match. The second type of error is when the system does not match someone who should match, called a false non-match. To understand the accuracy of a biometric system, it is important to understand both of these probabilities. Consider a typical biometric system used to control access to a facility. A false match means allowing someone in when that individual shouldn't be allowed. A false non-match means blocking someone who should be allowed. False non-matches are annoying; false matches are dangerous. Biometric systems can be tuned to optimize one factor over another, but it is a trade-off. If false matches are decreased, false non-matches automatically increases and vice-versa.