Polygraph exam definition

A polygraph exam is often referred to as a "lie detector test." It is one of a variety of testing procedures that seek to measure and evaluate the body's reaction to stress as an indicator of whether the subject is answering a question truthfully. It then renders a diagnostic opinion on the truthfulness or honesty of the subject.

There are various testing devices or procedures that may be used for this purpose, including polygraphs, voice stress analyzers, deceptographs, psychological stress evaluators or other similar devices.

Federal law, mainly the Polygraph Protection Act of 1988, prohibits use of pre-employment polygraph exams for most categories of private workers. The law exempts from the polygraph limits workers in public or governmental sector, certain federal government contractors, security personnel and certain drug company employees.