The key ingredient in successful polygraph use is a trained, experienced operator; the machine really has very little to do with "detection." Unfortunately it is impossible to train a sufficient number of operators to the necessary level of proficiency for mass screening, so most polygraph users simply lower the proficiency standard and go ahead anyway... with predictable results.
My favorite true story is of an Army Intel Major with the highest security clearances who applied to the CIA. The idiot who "boxed" him in New York for the CIA decided that he was "probably concealing illegal drug use." After three retests and five interviews the folks at Langley decided he was probably okay (he was), but by that time he had decided that THEY weren't... Marc de Piolenc Matthew X wrote: > > Lie detectors can be fooled > January 17, 2003 Lie detectors can work in specific cases, but are of > little use in general screening, a study has found. > The over-reliance on polygraph tests for screening can create a false sense > of security that may lead to less vigilance or the relaxation of other > methods of ensuring security, the committee found. – (Health24)