What is a Polygraph?

The word “polygraph” literally means “many writings”. The name refers to the manner in which selected physiological activities are simultaneously recorded. What we today refer to as a polygraph or lie detector is a scientific instrument, which is capable of simultaneously recording two or more channels of data. This data is the specific physiological changes produced by an individual when he/she is asked questions pertaining to a specific area under investigation. These recordings or graphs which are known as “polygrams” are then interpreted by a polygraph examiner.

What should I look for when seeking a Polygraph Examiner?

It is important that you choose a polygraph examiner who has been professionally trained.

What happens during a Polygraph Test?

A polygraph test consists of three phases: 1) pretest interview, 2) chart collection and 3) chart analysis and post-test interview.  No surprise questions.

How accurate is a Polygraph?

Recent research reveals that the accuracy of the new computerized polygraph system is between 92% and 96%. In the past 75 years, over 250 studies have been conducted on the validity, accuracy and reliability of polygraph testing (American Polygraph Association 1996 Polygraph Issues & Answers). Based on twelve separate studies involving 2,174 real cases since 1980, evidence suggests that qualified field polygraph examiners are 96% accurate in their overall decisions (Ansley, N. 1990 The validity and reliability of polygraph decisions in real cases).

How long does it take to conduct a Polygraph Test?

Depending on the complexity of the case and the issues being tested a polygraph test usually takes between 30-40 minutes (demonstration tests) to 2-3 hours.

Do nerves affect the results of a Polygraph Test?

No. It is expected that all people who undergo a polygraph test will be nervous whether they intend to answer questions truthfully or not. An examiner will look for action specific responses over and above the examinee’s heightened level of nervousness or anxiety. Typically an examinee remains nervous throughout the entire testing process not at one individual question. If nerves affected the result of a polygraph test, then nobody would ever pass a test.

Can you beat the Polygraph examination?

No, you can’t. If the examinee knows he/she is lying, the polygraph will detect the lie. Any experienced polygraph examiner can detect deception.