Monday, May 01, 2006

more reasons to hate polygraph tests

I loath polygraph tests, and this Post article about their use by Federal agencies like the CIA and FBI underscores why I hate them. It's because they are essentially bullshit.

For example, 25% of FBI applicants fail them -- do you think that's because the FBI draws an unusually untrustworthy bunch of people applying for jobs, or because there is a high false-negative rate? Well, a study in 2002 said that if you gave polygraphs to 10,000 people includine 10 spies, 1600 people would FAIL -- and two spies would PASS. Is a false-positive rate of 16% worth it when even the bad guys in question get away with it fully 20% of the time, in this sample? Couldn't that even foster a false sense of security -- "hey, this one passed, she must be innocent" -- while inspiring wasteful and destructive witch hunts against people innocent of all espionage charges who simply get nervous when asked if they are spies?

How is that useful? Some Federal agencies and private businesses like it as a deterrent, a way to get some people to confess and a way to make people think twice about doing something they wouldn't want to be asked about under the wire. But it's just a bunch of crap and the results of a polygraph vary widely depending on who is administering it -- it's an art, not a science, and leading questions can greatly skew the results -- and on how anxiety-prone the person taking it is. It's an easy cop-out, and no substitute for adequate security procedures and old-fashioned investigative skills.