What Happens in a Polygraph Test?

  • A polygraph examination first begins with a pre-test interview.   From that interview, (and possibly  questions supplied by others), the polygraph questions are designed.  They are unique to each situation, and will encompass the issue at hand.
  • Next, the actual Polygraph test is given, resulting in a collection of charts.
  • The Polygraph computerized charts are analyzed by the Polygraph Examiner.
  • And finally, the post-test results are given along with discussion.
  • A written report reflecting those results are printed and supplied at that time.  (We highly recommend avoiding those companies who will not provide an immediate written report and  discuss the test results with both parties).

Who is Using the Polygraph?

  • Today, every major law enforcement agency, every state police organization, and every large and middle size city police department has a polygraph operation. While many small cities and rural sheriff’s offices also have examiners, others depend on state assistance. Public defenders’ offices are often staffed with examiners, as are states attorney’s offices and other agencies in the criminal justice system.
  • Besides these legal situations, there are private situations.   Polygraph testing has become very popular determining truth in private homes, and marriages; and more specifically,  fidelity, and personal issues.
  • Also, polygraph is commonly used in a variety of theft situations.

In the Federal Government, the Federal Bureau of Investigation, the Drug Enforcement Agency, Homeland Security and the United States Secret Service, Customs, and similar agencies regularly use the polygraph. The divisions involved in criminal investigations and intelligence of the Army, Navy, Air Force and Marine Corps use the polygraph, as do the major intelligence agencies, including the Central Intelligence Agency. The polygraph is not confined to the United States. It is regularly used by law enforcement agencies in Canada, Japan and Israel, and to a lesser extent by law enforcement agencies in more than twenty other nations

How It Works:

Fear is the greatest psychological factor – fear of exposure. The administration of the polygraph examination requires the monitoring of these physiological changes that occur during the process of the examination.

Three specific physical factors are measured: the respiration system, the skin response and the cardiovascular system. The computerized reading of these three responses together, make the polygraph test a powerful tool for determining truth.


  • Psychological Theory of a lie: Emotional changes occur in a person causing physiological changes that can be recognized and diagnosed.
  • Psychological Make-up: A person’s fears, anxieties and apprehensions are directed to the areas that hold the greatest threat to his well-being or self.
  • Psychology of Test Questions: The test is structured so as to pose a challenge to the security of the examinee, and force him/her to focus his/her attention to that specific area of the test.


The pre-test examination is probably the single most important part of any polygraph test.  The person to be tested in most cases is apprehensive or fearful.  They may be upset at being suspected of wrong doing, nervous, suspicious, or even angry at being accused. Thoughts of inaccuracy of the instrument or whether or not the Examiner will be fair, are common and expected.  This is why well experienced examiners are a NECESSITY.

The pre-test is an information gathering talk session.  The information is of a personal and factual nature and reflects the examinee’s past and present.  It is essential for the Examiner to feel like he “knows” the person he is to examine and for the examinee to feel that he is to be tested fairly.  Additionally, no examination will be given unless it is voluntary.

The details of how polygraph testing works will be explained. It is necessary for the individual to understand the concept of polygraph and what he/she is about to experience.  He/she must understand that “the polygraph works”; and that truth WILL be forthcoming.

It is also necessary for the Examiner to know the  case facts.    He will discuss the details of the case with everyone involved.   Understanding the specifics are a necessity to pinpoint the answers needed, as each case is different.

Types Of Questions:

Test questions are reviewed IN ADVANCE with the examinee.  Contrary to what has been seen on TV, polygraph is not a shock process.  The examinee will know and completely understand each question prior to testing.  He/she is also advised that these questions, and only these questions, will be asked during the course of the examination.

Basically, there are two types of questions:

There are those questions designed to establish a normal tracing of responses during the test. They have little or no intensity to them.

Then, there are questions that deal with the issue or incident for which the polygraph test is being administered.  Instructions are given to the examinee as to how the actual examination will proceed.


At the conclusion of the exam, the Examiner will ask for clarification concerning any answer that may have indicated a deception.  To avoid an inconclusive opinion, the Examiner may go back over a question again, and say “you seem to be having trouble in the area of X” (the relevant item), and ask the examinee if he or she can think of a reason for having a strong reaction to that question.  This is to be certain that there is no misunderstanding to the question, which is then explained and re-asked in a subsequent charting.  Alternately, if the reaction remains unexplained to the Examiner’s satisfaction, the issue may be probed in more detail.  After the testing is completed, the results will be analyzed and explained.

Immediately following the exam & computer analyzation, you will receive a written report.