Today's useless fact - How do polygraph tests work, and how accurate are they?

What is often referred to as “the polygraph" is actually a set of relatively complex procedures for asking questions and measuring physiological responses in order to detect deception or establish truth. Polygraph testing is employed for a variety of uses, ranging from ascertaining the guilt of a criminal suspect to assessing the honesty of a prospective employee. Because different polygraph procedures are required depending on intended use, it is necessary to consider validity by polygraph technique and situation.

The courts have found themselves disagreeing on methods to establish validity for purposes of admissibility of evidence, where the critical focus of such judgment should rest. In addition, courts are inconsistent about what decision to make on the basis of judicial findings of fact regarding the validity of a diagnostic or predictive device. So, in summary there is really no agreement as to the accuracy of polygraph testing. People have been known to "beat" the machine and also there have been false positive responses from people telling the truth. Check out the links in our Polygraph category for more.