Someone I know had to take a polygraph when applying to be a deputy sheriff. This person said he failed a question that he absolutely did not lie on. He also said he "out and out lied" on one question, and he passed it! That should tell you that polygraphs cannot be trusted to be accurate. There are so many variables too. If a person has a headache it can make a difference! (The person I know had one that day) and also the examiner is a biggie. They are all different, and they say some are better than others. I more or less "believed" in polygraphs before this person told me about their experience. No longer the case now.