I'm no expert, but I HAVE run across several articles about polygraphs.
They appear to be pseudoscience. Yes, they do have a bit more real
science behind them than those glorified dowsing rods that the US Customs
people were using to detect illegal aliens last year. But if we rely on
polygraph results, yet they return many false positives, then lives can be
ruined when honest people are falsely judged to be liars.
If HONESTY is the goal, then the very first requirement is lots of honest
(double blind) testing of the reliability of polygraph tests.