The false acceptance rate, or FAR, is the measure of the likelihood that the biometric security system will incorrectly accept an access attempt by an unauthorized user. A system’s FAR typically is stated as the ratio of the number of false acceptances divided by the number of identification attempts. (Webopedia)
The false rejection rate, or FRR, is the measure of the likelihood that the biometric security system will incorrectly reject an access attempt by an authorized user. A system’s FRR typically is stated as the ratio of the number of false rejections divided by the number of identification attempts. (Webopedia)
These days there is a lot of emphasize on FAR (False Acceptance Rate). It is good that clients are getting aware of these terms and asking the right questions before implementing a solution.
However, FAR only provides half the information. When selecting a biometric solution, we need to find out what the False Rejection Rate (FRR) is at the said FAR.
So when a biometric solution provider claims to have a very low FAR, it is very important to find out what is the FRR at this ‘low’ FAR. Then depending upon the application one needs to evaluate whether the FAR & FRR ratio is acceptable for the application.
In a practical scenario a low FAR & a high FRR would ensure that any unauthorized person will not be allowed access. It would also mean that the authorized people will have to put their finger on the device several times before they are allowed access.
Therefore, it is good to have a very low FAR, but please remember that if this low FAR is coming at the cost of high FAR then the solution needs to be re-evaluated.