It is complete pseudoscience. In the Penn and Teller's BS episode about it they have a guy who teaches people how to get whatever result they want by controlling their anal sphincter. Apparently it's not complicated.
It is, however, still a part of getting or maintaining clearance. A friend of mine wound up changing jobs simply because he failed the polygraph twice and didn't want to bother going in for a third.
It's not used to detect lies, it's used to measure how a person reacts under pressure. It's a low-level torture device meant to intimidate.
The fact that police services can use it to extract confessions is just a nice bonus, and it's really a really cheap alternative to conducting a complete and thorough investigation. Police policy has for a long time favored confessions over investigations.
Yap it is just an interrogation. However, knowing about how the polygraph is ineffective and letting the administrator know will often result in 'FAILURE'. They will specifically ask questions related to polygraph terminology (lingo, abbreviations) to see if you are familiar.
It effectively lets through psychopaths, very good liar or those that know how polygraphs work and presumably practiced passing it.
The example here is somebody who apparently needs to take one to access some confidential information - and clearly they take a pass/fail seriously, so it seems some (presumably US?) government agencies do take it seriously enough to make passing one a security requirement.
Good point. A quick Google search doesn't seem to bring up any laws that prevent employers from using polygraph results in determining whether to hire or fire someone.
