So do I, and I have been polygraphed.
The problem with a polygraph is that it is NOT a lie detector. It will accurately measure respiration, heartbeat, and skin resistance. It assumes that when a person practices deception, certain physiological parameters will change as well.
The problem is, these paremeters may or may not change, and they do not change uniformly in all people (or for that matter in the same person). The ultimate arbiter of the truthfulness or deception of a statement is the person administering the test. And different testers, when presented with the same polygraph data, provide different opinions.
This is the key word: OPINION. The results of a polygraph are an OPINION. And because of this, they are not admissible in criminal proceedings.
I'm a test engineer. The tests I design must be repeatable and reproducible in order to be useful, and I use tools to gauge the repeatability and reproducibility of my tests. A polygraph is neither repeatable nor reproducible.
Frank Rizzo, Philly's former Mayor and Police Commissioner, was an ardent supporter of polygraphs until he failed one.
FWIW, I passed mine.
Bill Sullivan