American Polygraph Services

Dedicated to Truth Through Professionalism

Frequently Asked Questions:


Q. Is a Polygraph the same as a "Lie Detector"?

Yes. The polygraph instrument is a scientific diagnostic instrument which is often called a "Lie Detector'. However, it would be more appropriate to call it a "truth verifier".

Q. How accurate is a polygraph?

The polygraph has been proven to be up to 98% accurate, a figure much higher than most other scientific tests. There are times when a test is termed "inconclusive," meaning that no decision is offered to determine the truthfulness of the subject. This is neither a help nor a hindrance to the subject, as many other factors can influence the Pre-testability of the subject, such as recent emotional trauma or medication.

Q. What if I feel guilty about taking the test? Will it affect the outcome?

Many innocent people feel guilty about taking a polygraph exam. The Examiner will reassure and relax the subject. Nervousness will not show an innocent person to be guilty.

Q. Does high blood pressure affect the accuracy of the polygraph test?

No. While blood pressure is one of the physiological reactions measured, it does not affect the accuracy of the test. However, if you are taking medication for it, be sure to mention it to the examiner so that he can evaluate its effect on the test.

Q. Will I know what the questions are prior to the test?

Yes. Each question to be asked will be read to you and explained before you take the actual test. There will be no surprise or 'trick' questions.

Q. Will I know the results of my Polygraph test?

Yes. The American Polygraph Association Standards and Ethics Committee require that the examinee be given the results if requested.
Q. How long does it take to administer a Polygraph test?

It usually takes from 1 1/2 to 3 hours to properly administer a Polygraph test.
Q. Why does the Polygraph test take so long?

The test includes an Introduction Phase, in which the Examiner will obtain general background information for assessment purposes, and obtain medical history information to determine if any medical problems will interfere with the testing procedure.

In the Pre-test Phase the Examiner will explain how the Polygraph works, and discuss the facts of the case to determine the exact issues to address during the examination. From this the Examiner will formulate the questions to be asked and then review them with the Examinee.

In the Actual Test Phase the questions will be asked, and the questions may be repeated 2-3 times.

In the Post-test Phase the Examiner will discuss the results of the test with the examinee.

Q. Who should not take a Polygraph test?

  • Anyone who is being forced to take it.
  • Any person with a serious heart condition, unless his doctor has given written approval.
  • A pregnant woman, unless her doctor has given written approval.
  • Any person who is determined to be mentally incompetent.
  • Any person who has a respiratory illness or cold.
  • Any person who has nerve damage or paralysis.
  • Any person who has had a stroke or is an epileptic.
  • Any person who is extremely fatigued.

Q. What drugs can affect a Polygraph test?

Anti-depressant medication (i.e., Lithium, Prozac, Valium or Xanax). These drugs DO NOT allow someone to 'beat' a polygraph, contrary to some claims. It will give skewed results that are immediately seen in the Pre-test Process. Only the Examiner, through the Pre-test Process, can determine if the subject can take a Polygraph while on these drugs.