Employee Polygraph Testing (Lie Detector Test)
Employee Polygraph Testing is a controversial topic, mainly because most of us are not question whether it is legal. What are the rights of employers when it comes to polygraph testing; and what rights do employees have been asked or even instructed to undergo polygraph test?
What is a polygraph?
A polygraph is an instrument that measures changes in a person’s body that are associated with stress or deception. It measures heart rate, breathing, blood pressure and the electronic conductivity of the skin. It measures the smallest changes and therefore is able to record deception based on the body’s physical responses to the stress caused by not telling the truth.
When we lie about something important, changes occur in our bodies that we have no control over. The polygraph records these changes. The Autonomic Nervous System in our bodies consists of two systems – the Sympathetic and the Parasympathetic. When we lie, physiological changes occur at the Sympathetic level, beyond our control, and the polygraph records these Sympathetic arousal responses.
Polygraph tests a very accurate. The average accuracy: 98%!
Can I force an employee to take a polygraph test?
No. You need their written permission at the time or it should be included in the employment contract that both the employer and employee have signed before. Every polygraph examination also needs to be preceded by a “polygraph consent form” with the written consent of the employee.
Can I end the contract of an employee for failing a polygraph test?
No. The information can only form the basis of an investigation. Further evidence is needed which proves, within a “balance of probability”, that an offense has taken place. The polygraph can therefore only be used as supporting evidence in a disciplinary hearing and it can never be accepted as evidence in a criminal trial, where guilt has to be proven “beyond reasonable doubt”.
How many questions can I ask during one test?
The success of a polygraph examination is based on the composition of the questions, therefore the series of questions to be asked should be carefully formulated. Preferably, don’t ask more than four relevant questions during the course of the test.
Can a pregnant female be polygraphed?
No (as a rule). Even though there is no medical evidence that a polygraph can cause harm to the mother or unborn child.
I’m told that if I’m very nervous, I might fail the test. Is this true?
No. Everyone who takes a polygraph examination will be nervous, whether they intend lying in the exam or not. The polygraph exam identifies truth and deception, no matter the level of nervousness in the subject.