Every lie detector should begin with a game of high-low: The subject writes down a number between 1 and a 1000 and puts it in their shoe, the questioner needs to get the right answer. Since the questioner needs only 10 questions to get the right answer (+ control questions), it provides a practical calibration of whether the test is worth a damn or not.

Prediction: No one will ever use my practical calibration of whether the test is worth a damn or not, until lie-detector technology is actually worth a damn.