Eight Percent of the Time It Works Every Time

The Transportation Security Agency (TSA) is the embodiment of government incompetence. It has failed 95 percent of red team exercises, which doesn’t bode well for the agency’s general ability to detect weapons before air travelers are able to enter the “secure” area of an airport. However, the United States doesn’t have a monopoly on government incompetence. The United Kingdom (UK) also has its own program that has a failure rate of 90 percent:

A British police agency is defending (this link is inoperable for the moment) its use of facial recognition technology at the June 2017 Champions League soccer final in Cardiff, Wales—among several other instances—saying that despite the system having a 92-percent false positive rate, “no one” has ever been arrested due to such an error.

Of course nobody has been arrested due to a false positive. When a system has a false positive rate of 92 percent it’s quickly ignored by whomever is monitoring it.

False positives can be just as dangerous as misses. While misses allow a target to avoid a detection system, false positives breed complacency that quickly allows false positives to turn into misses. If a law enforcer is relying on a system to detect suspects and it constantly tells him that it found a suspect but hasn’t actually found a suspect, the law enforcer quickly ignores any report from the system. When the system does correctly identify the suspect, there’s a good chance that the law enforcer monitoring it won’t even bother to look at the report to verify it. Instead they’ll just assume it’s another false positive and continue sipping their tea or whatever it is that UK law enforcers do most of the time.