Frequently Asked Questions About Polygraph

If you have never been subjected to a polygraph examination in Knoxville, then you may only know a little about the process beyond what is depicted in old detective movies! With that in mind, we have decided to answer a few of the most frequently asked questions that we receive in regard to polygraph exams.

What is a Polygraph?

A polygraph machine is a scientific device designed to read and display specific physiological responses to determine if a subject is telling the truth. Hence, it is often referred to as a ‘lie detector.’ The word ‘polygraph’ stems from the Greek language and loosely translates as ‘many writings’ in reference to the various calculated readings.

What Does a Polygraph Machine Record?

Modern polygraph equipment can record five or more types of physiological data. Most commonly, breathing rates, pulse, blood pressure, skin moisture changes, and blood vessel dilation. The exact data collected will vary depending on the make and model of polygraph equipment being used. The data is collected by the various sensors and presented to the examiner via specialized polygraph software. The examiner will then read this data and determine whether or not the subject is telling the truth. The accuracy of a polygraph examination in Knoxville may vary depending on the ability and experience of the examiner. It is important to work with a qualified and reputable polygraph expert if you want to get the best possible results from your test.

Is the Polygraph Examiner on My Side?

When you hire a polygraph examiner in Knoxville, you may wonder if they can be trusted to be on your side, especially if you did not initiate the test. However, a reputable polygraph examiner should be an independent and neutral party. Regardless of who is the one paying for the exam, they are only on the side of the truth. Their job is to determine if the subject is being truthful and report on their findings. It is important to work with a polygraph examiner in Knoxville with an excellent reputation to back up their integrity. For example, Kendall Investigations owner Kendall Shull is a former FBI Special Agent who was in charge of the entire FBI polygraph program. He is also the only person in the world who has attained a Masters of Science in Polygraphy. It’s safe to say that he can be trusted to act with integrity and professionalism when conducting a polygraph examination in Knoxville.

Can I be Forced to Take a Polygraph Examination?

We are often asked if someone can be forced to take a polygraph examination in Knoxville to prove whether or not they are lying. The short answer is NO! Polygraph testing must be voluntary, both legally and out of practicality. Certain career opportunities will require you to take a polygraph exam for the purpose of government security clearance or as a condition of employment in certain industries. Still, those are opportunities an individual chooses to pursue, knowing that a polygraph is one of the requirements. You cannot, for example, force your spouse to undergo a polygraph examination in Knoxville because you believe they are cheating. They would have to agree to your request of their own free will and are not obligated to do so.

Is a Polygraph Exam Confidential?

When you take a polygraph examination in Knoxville, the results of your test are completely confidential. The result can only be disclosed to parties that you have agreed to prior to the exam. For example, you may decide to share the results with your spouse, therapist, or lawyer.

How Long Does a Polygraph Exam Take?

The exact length of a polygraph exam may vary depending on the examiner and even the purpose of the test. However, as a general rule of thumb, it should last for between 90 minutes and two hours. This includes an interview proper to the exam and the test itself. The more complex the reasons for the exam, the longer it is likely to take.

How Many Questions Are Asked During a Polygraph?

Unlike what you see in the movies, polygraph exams are not made up of multiple questions, and the questions are never a surprise to the subject. Your polygraph examination in Knoxville should cover one specific question or concern, and the questions asked will all relate to that. The test questions will be determined after the interview portion of the appointment, and the exact wording will be agreed on between the subject and the examiner. The examiner should never ask a question out of the blue that has not been previously discussed.

How Should I Prepare for a Polygraph Exam?

When someone books with us for a polygraph examination in Knoxville, they often ask what they should do in order to prepare for the test. The answer is - nothing! You don’t need to make any special preparations. In fact, it is best if you just go about your regular routine on the day of your examination. Make sure you are well-rested and have eaten so that you are not distracted by hunger or fatigue. You should also take your regularly prescribed medications as you would any other day.

These are just a few of the frequently asked questions we receive regarding our polygraph examinations. If you have a question we have not mentioned here, please do not hesitate to contact us; we are always happy to provide guidance and help put your mind at ease if you need to take a polygraph test for any reason.

Uncover the truth!


Ken Shull served as a Special Agent with the FBI for almost 25 years and was head of the FBI Polygraph program until his retirement in 2001. At that time he set up the Kendall Investigations practice as a private investigator in Knoxville, TN offering Polygraph services, private investigations, and security guards. Ken is a member of the American Polygraph Association and The American Association of Police Polygraphists.

The Truth is Still the Truth Even if No One Believes it, A Lie is Still a Lie Even if Everyone Believes it.