Chapter 10. An Introduction to Statistical Measures of Biometrics

To know how well something performs , we must be able to quantify the performance. For automobiles, we measure gas consumption; for heating and cooling units, we measure effectiveness in British thermal units (BTUs). Biometrics have their own similar performance measures.

To know if a car is getting good fuel economy or if a heater or air conditioner is doing its job, we look at what the statistics mean. We then compare them to our expectations or some other accepted norm. At no time does knowing how the performance measure was calculated impact our ability to evaluate performance. Similarly, for biometrics, how a performance measure is calculated is of little value. There are exceptions to this statement, which will be discussed. In general, just knowing what a performance measurement means is sufficient. For our purposes, the statistical measures to be used for biometrics are:

• FAR (False Acceptance Rate)

• FRR (False Rejection Rate)

• FTE (Failure to Enroll)

• EER (Equal Error Rate)

A discussion of each statistical measure follows .