wrote on Dec 20^th, 2002 at 7:06pm:

Dear stopnik, You bewilderment is justified because there are not any scientific means to predict future behavior.  The NAS study has confirmed that polygraph screening as used in employment examinations by itself has no better ability to predict future spies or security risk than chance guessing (actually even less than chance when you acknowledge that only a small percentage of applicants would be spies to begin with).

Actually, IIRC it's even worse:  NAS concluded that the polygraph adds no incremental value to the hiring process.  IOW, there's no reason to use it, and a lot of reasons not to.

Skeptic