About 6 years ago the local police dept. one county over from where I practice bought a bunch of VSAs and trained their cops to use them. Within 6 months every cop in the department considered them a joke. One of the officers remarked to me that he could get more reliable results using a Magic 8 Ball. That PD no longer even bothers to use them - they are in a closet gathering dust.
“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.