I recently applied to the Philadelphia PD and scored near perfect on all of my tests.  I got to the polygraph stage with no worries at all.  When I took it the first time, the officer asked me all the questions about drugs, criminal history, etc.  I filled out the form and gave it back then proceeded with the machine hooked up.  Fifteen minutes later it was over and the female officer told me I failed without even really looking at it.  When I asked her what questions I did not "pass" on she said it was not up to her to discuss the matter and that I needed to reschedule the exam for a different date.  I rescheduled and the same lady gave me the test again a week later(only later did I realize that this in itself was against the PPD's policy).  I took the test once again with the same outcome.  I assumed I had passed since she did not tell me otherwise and asked when the next step would be.  She said that she would review the exam results then told me to call my background investigator in a week.  She apparently did not know this time if I passesd as quickly as the last.
I called a week later to find out that the results were not in yet.  I called for a month until my investigator told me he just got the results in and I failed again.  When I asked him what took so long he told me sometimes that happens(great excuse huh?).  Anyway, I was told to wait till they offered the next test(6 mos. later) and re-apply for the whole process again.
Does anyone know of any reason why 1. She could not tell me right away the second time or 2.  Why I was only given 2 times to take the polygraph when others took it as many as 6 times?  If anyone know the reason or anyone had the same experience please email me.  

Now that you mention it, I was put in a small room with a heater on.  I never though about that since it was winter time but there were vents supplying regular head from building furnaces then there was a space heater against the wall of the room which is only about 6 foot square.  Trust me, it was hot as hell in there.  The other features of this room that lies in the basement of the building were 1. a two-way mirror and 2. A framed quote from I think Robert Frost about a pallipation of one's blood with always reveal a lie or something to that nature.  They make you sit in this room for about 30-45 minutes before you take the actual test.  This room in itself was probably one major tactic to put a person's tension levels through the roof.  Thanks for helping me remeber that.