“Within 6 months every cop in the department considered them a joke.”
I’m not surprised... It’s a tool and it has it’s uses. However as it turns out these things are more of a truth detector than a lie detector. Your looking for stress related changes in voice. The fact that there IS stress detected doesn’t mean that the subject is lying since stress can be caused by other things, however lack of stress is a very good indicator that the subject is telling the truth.
It is not just stress in the voice. It is many many things, so many that I don’t think a computer could sort them out. When I listened to and watched BUY-a-Lick’s statement it was tone of voice, the words she used, the space between words, the frequency of her voice went up slightly, facial expressions, eye brows did not go up, eyes where not wide open, when recounting the past the head will cock to one side or the other and hers did not. Just her trying to stop the beginning of a cheshire grin numerous times was enough to determine she was lying and I did not need any equipment to determine that fact. The equipment still needs an operator sensitive to other factors to be useful.