Bill,
I have to admit, that is hilarious, even if I am the target of the joke.
EosJ,
10% collateral damage is not acceptable, you're right. At least not when you are in that 10%. Sometimes I find it unacceptable too, I must confess. Whether passing polygraphs or administrating them, I've never had to face it from the side of the person falsely accused. Regardless of my ego, which I gladly admit, and despite Digithead's contrary opinion, I do feel sympathy for those treated with injustice.
That said, though, the agencies most polygraphers work for all want to get rid of the bad fish in the net, even if it means killing some of the good fish at the same time. When there are thousands of qualified applicants, and you have a process that you believe--rightly or wrongly--is correct most of the time, you use what you have. Is that unfair? Not to those hired, but it is unfair to those falsely accused, as well as to the rest of us when a truly bad fish escapes the net and swims in our waters. I just don't believe that either the false positive or the false negative happens as often as some of you would like to believe. Just because something may have happened to you doesn't make it a very common occurrence.
You are right about something else, I think: Maybe I haven't come across a truly prepared, determined person in an exam--a truly prepared person determined to beat the test despite past criminal behavior. And if I have, I didn't know it. What I have come across are people who are determined but not prepared, even though they've come here and read all of George's advice. Those people fail, after looking really stupid and being very embarrassed.
Finally, Digithead,
Your math makes sense in a purely mathematical world. Your skill with numbers is undeniable and impressive. My esteem for you has risen lately. But there are variables involved in the polygraph that you just can't figure out, no matter how you manipulate the statistics. Why does the polygraph work so well in the real world? I don't have all the answers, but from my experience I have seen time and time again that it does.