Q. How accurate is the polygraph?
A. The polygraph technique is very accurate, however, it is not infallible. According to the American Polygraph Association, over 250 studies have been conducted over the past twenty-five years on the accuracy of polygraph testing. It is estimated that the accuracy of the results is in the range of 90 – 95 %. More recently, research has shown that the accuracy of computerized polygraph testing is 98 %.
Q. Is the polygraph like the lie detector?
A. Yes. The polygraph instrument is a scientific, diagnostic instrument which is often called the “lie detector”. It would be more appropriate, however, to call it the “truth verifier”.
Q. I am telling the truth but I am nervous about taking a polygraph examination. How does the polygraph establish the difference between the state of nervousness and reactions as a result of lying?
A. It is quite normal for an innocent person to feel nervous and the polygrapher is very aware of this. Nervous reactions which are recorded on the polygraphic charts are not interpreted by the polygrapher as a manifestation of deception. Nervous reactions are completely different from those reactions that are recorded when a person is deliberately lying.
Q. Can I know what the questions on the polygraph examination will be beforehand?
A. Yes. You will be informed of the exact wording of each question that will be asked of you during the course of the polygraph examination. There will be no “trick” questions.
Q. How long does a polygraph examination take?
A. A polygraph examination takes about two to three hours, however, some may take more or less time, depending on the nature of the issue under investigation.
Q. Why does a polygraph examination take two to three hours?
A. The examiner will give a detailed explanation of the polygraph procedure, how the polygraph works, and he will answer any questions that the examinee may have. The examiner will also inform and discuss the result of the examinee’s polygraph examination.
Q. Can you carry out tests in any foreign languages?
A . CPS can carry out tests in any language via a team of highly skilled linguistic experts available to us.