How to Select an Examiner

How do I choose the right examiner for my lie detector?  Selecting a qualified examiner can be a challenging process, considering how much is sometimes at stake. We understand the importance of this decision, so we will never refer you to an untrained examiner or one which uses a technique not validated by scientific research. If done correctly, specific issue polygraph testing is 90 to 95% accurate. Please review the qualifications listed below to learn how to hire the best examiner for your situation.  The Global Polygraph Network ® has already screened its members for these requirements so you don’t have to.

A Basic How To

We make sure your examiner has attended and graduated from an accredited polygraph training school. The American Polygraph Association is currently the accrediting organization for these schools and assures that the schools meet a minimum standard for instruction of primary polygraph students. Don’t hesitate to contact the examiner’s school and/or the APA ( for verification of accreditation.  SHORTCUT:  GPN verifies that its examiners have completed training at accredited polygraph schools.

The more polygraph experience an examiner has, both in terms of years in the business and number of total exams, the more likely it is that this examiner can deal with any situation or resolve a difficult testing issue. All GPN Members or Supervisors must complete a specified number of exams to qualify for membership.  In some cases we will refer you to a Member who is Supervised by a senior examiner (over 10,000 exams) so you will have the benefit of getting two examiners for the price of one.  SHORTCUT:  We make sure your examiner has sufficient experience or is working with a senior examiner who does.

Some examiners have lots of overall experience, but not so much with the type of case you need help with. We make sure your examiner has experience with your type of case or is being supervised by one that does. 

Even though an examiner have many years of overall experience, if he/she is not currently testing on a regular basis that examiner’s skills will not be as sharp as someone who provides frequent tests. All GPN examiners are actively in the business of providing polygraph testing. We will not refer you to an examiner who only provides polygraphs as a hobby or sideline.

Technology evolves. Polygraph techniques and equipment are updated often, so even though an examiner may have a great deal of experience, if they are not using the latest techniques and validated testing formats the test will be substandard and will not stand up to expert scrutiny.  SHORTCUT:  All GPN members are required to maintain continuing (advanced) polygraph education.

The only way to stay current in this profession is to belong to a professional organization that sets membership requirements, establishes certification criteria, and provides continuing education opportunities. There are only four credible national organizations: American Polygraph Association (APA), American Association of Police Polygraphists (AAPP), National Polygraph Association (NPA), and the Global Polygraph Network ® (GPN). We do not recommend hiring an examiner who does not belong to at least TWO of the above organizations.

Nearly half of the U.S. states require polygraph examiners to be licensed. If your exam is to take place in one of these states, we ensure that the examiner is properly licensed.  If an examiner is operating in a non-licensing state or country, then it is not possible for the examiner to possess or obtain a license in that state or country.  In areas that do not offer licensing, belonging to professional organizations becomes extremely important.  SHORTCUT:  GPN verifies its examiners licensing.  Note that licensing only ensures that you are hiring a legitimate examiner, but it does not ensure the quality of the exams.

Examiners should stand behind their work and should allow you to get a second opinion if you want one.  SHORTCUT:  All GPN members must provide a complete set of charts (polygrams) from your polygraph upon request so you can have them reviewed by another examiner. A qualified QC examiner must have completed training at an APA-accredited training facility and must be specifically trained in the technique used by your GPN examiner. You should avoid hiring any examiner who is not willing to release his/her work product for QC review.

We require that your examiner is using fully-operational computerized (digital) equipment. Some examiners try to get by with poorly maintained instruments, with some units barely working at all.  GPN members maintain their equipment to the highest of standards.

There is a great deal of literature available regarding countermeasures, or how to “beat” the polygraph. A quality examiner will have training to easily identify when a person is attempting these techniques, and will use CM detection monitors to help them catch people who attempt to alter their test results. Use of this detection equipment is now mandatory for all polygraph exams.  SHORTCUT:  All GPN examiners use CM identification equipment.

If you intend to use the polygraph results as evidence, it is often helpful to select an examiner who has testified and/or been approved as an expert to present polygraph evidence in court.  However, just  because your examiner has not testified before does not mean he/she is less qualified than one who has.

A simple Google search can tell you a great deal about the reputation of an individual or company.  GPN’s owner, Michael Martin, has been a certified polygraph expert for nearly 40 years, has conducted over 11,000 exams, and has published two textbooks for polygraph examiners. GPN is the world’s oldest and largest polygraph referral service. All GPN examiners are thoroughly screened, and must meet certain experience and certification requirements to become members. While we do screen our examiners carefully, we also rely on customer feedback to determine if there are any problems we should be aware of. The Global Polygraph Network ® is also an Accredited member of the Better Business Bureau which tracks complaints and requires compliance with good business practices, and has given GPN it’s highest rating of A+. You can find GPN’s BBB information by clicking HERE.  We strongly recommend checking the BBB rating of any professional or business you consider doing business with.

Generally speaking, the more relevant questions asked in a polygraph exam the less accurate the results will be. A single-question test is the most accurate exam you can get, and is the exam type used for most polygraph research. Many examiners will allow 3 or 4 questions to be asked in an exam as long as all these questions are on the same general topic. If an examiner tells you that he/she can ask 10 or more questions on an exam, you will be getting what is called a screening test, not a true polygraph. The results of a screening test can not be relied on and must be verified by running a separate exam on each relevant question.  Your GPN examiner will suggest the best method to be used for a given situation.

Never trust an examiner who will not put his/her test results in writing. If you hire a GPN member, you are entitled to a written report of your exam at no additional charge. This report should include the purpose of the exam, the relevant questions asked, the answers given, and the examiners opinion regarding the examinee’s truthfulness when giving those answers.  SHORTCUT:  All GPN examiners must provide you with a written report at no additional charge.

Polygraph is considered the most accurate method of lie detection today. One of the reasons for this is that the polygraph records various different aspects of a person’s physiology, not just one. Different people show reactions in different ways. To look at only one aspect of physiology is to remove a great deal of information the examiner could have used. Voice Stress Analysis (VSA or CVSA) only measures one aspect of physiology. Even if we allow that VSA can detect stress, that is not an indicator of deception. If a polygraph examiner suggests or encourages the use of Voice Stress technology, that examiners training and qualifications may be questionable. SHORTCUT:  No GPN examiners are currently using or supporting the use of VSA technology. Click HERE for more information about Voice Stress validity.


Established in 1987, Global Polygraph Network ® is the world’s largest and most trusted polygraph (lie detector) company with services available at hundreds of locations by highly-trained experts all over the world. Avoid “discount” polygraph frauds and “over the phone” testing scams. We only provide real polygraphs by real examiners. Trust our A+ BBB rating, up-front pricing, and written guarantee.