The success rate of up to 90% claim

The success rate of up to 90% claimed for lie detectors is misleadingly attractive. Ifwe refer such a figure to a company with 50 employees, 20 of whom are thieves,the lie detector could catch 18 of them but doing so would place 32 innocentemployees under suspicion. The problem for the management would thereforebecome one of deciding how much industrial unrest they are prepared to cause inorder to eliminate theft. What concerns research workers even more, of course, isthe fact that a certain number of innocent people are bound to be convicted ofcrimes they have not committed.