ctt,

I can easily see where one might believe this to be true.  Sometimes, when looking at FACTUAL statistics stated by a particular agency (e.g. current failure rate for FBI pre-employment polygraph is 50%) it is almost inconceivable as to why these agencies would continue use of this tool.

However, I'm not sure that a "psychological test" is how these agencies now perceive the polygraph.  Although some more than others, it is apparent that some do believe the polygraph is a fail-safe method of detecting deception.  Let's face it, some liars are uncovered.  But to use it simply as a test to see how one reacts in an "interrogative" situation, I don't see how the FBI's 50% failure rate would then be explained.  I find 50% of applicants cracking or blowing up during the examination ALMOST as hard to believe as 50% of applicants actually lying.  Both are absurd.

Sadly, I think we are dealing with two main opponent-groups:  those who subscribe to the polygraph mantra and believe that it works (of course, if it is your income provider, you would naturally claim to believe in it) and the concept of bureaucracy - too much is needed (these days anyway) to put a change like that in place.  This is the bureaucrats' opinion, of course.  

That's just how I feel about the situation.  I see on other boards focused more on employment issues people talking about being "evaluated" at all phases of processing including the polygraph - meaning the examiner is looking at how you are dressed, etc.  Maybe this holds true for examiner bias but otherwise I just don't believe this to be the case.  I think the polygraph is still used solely based on the belief that it is an effective deception detection method.

Sorry for the long post, I tend to be overly verbose when posting here.