The following is a list of the most FREQUENTLY ASKED QUESTIONS about polygraph (lie detector) testing.
If you have a question that is not addressed on this web site, please feel free to write to us at firstname.lastname@example.org.
This site is sponsored by the Global Polygraph Network
What issues or situations can a polygraph exam be used to resolve ?
A polygraph (lie detector) exam can be used to determine truthfulness regarding the facts of virtually any situation. Some examples of situations that polygraph testing can be used for include:
- Drug abuse
- Alcohol abuse
- Verification of witness statement
- Verification of victim statement
- Sexual assault
- Child abuse
- Insurance fraud
- Sex offender testing (post-conviction)
- Employment issues (in some cases)
Can anyone ask anyone else to take a polygraph exam ?
With a few exceptions, if a person is willing to take a polygraph exam it is permissible to do so. However, no one can be forced to take a polygraph. If the examinee (person taking the exam) is under 18, parental consent will be required. In the case of an employer wishing to have an employee take a polygraph, there is a federal law in the United States known as EPPA which limits this type of testing. Please click HERE
to get more information about employee testing. There are also some states that prohibit testing of sexual assault victims.
How accurate is a polygraph exam ?
Done correctly, by a qualified examiner, polygraph results have been determined by independent research to be between 80 and 98 percent accurate. It remains the most accurate technology presently available to identify deception.
The American Polygraph Association has a compendium of research studies available on the validity and reliability of polygraph testing. The 80 research projects published by the APA since 1980 involved 6,380 polygraph examinations or sets of charts from examinations. Researchers conducted 12 studies of the validity of field examinations, following 2,174 field examinations, providing an average accuracy of 98%
. Researchers conducted 11 studies involving the reliability of independent analyses of 1,609 sets of charts from field examinations confirmed by independent evidence, providing an average accuracy of 92%
. Researchers conducted 41 studies involving the accuracy of 1,787 laboratory simulations of polygraph examinations, producing an average accuracy of 80%
. Researchers conducted 16 studies involving the reliability of independent analyses of 810 sets of charts from laboratory simulations producing an average accuracy of 81%
. The average accuracy for all 6,380 exams is 88%
. However, new industry standards require that a
particular technique be at least 90% accurate for that technique to be
"validated." Make sure your examiner is using a validated polygraph
Has polygraph been accepted by the scientific community ?
Research scientists and psychophysiologists are generally in agreement that polygraph examinations, if done correctly, are a valuable tool with significant accuracy and reliability. Within the last few years, the American Society for Testing and Materials
has established industry standards for polygraph testing (also known as Psychophysiological Detection of Deception). The establishment of industry standards by an independent organization is just one more indication that the polygraph process has been validated as an approved and tested scientific procedure.
How many questions can be asked in a polygraph ?
Research statistics on polygraph accuracy (see above) are all based on a single-question single-issue exam, which is the most accurate format possible. As more questions are added to an exam, the overall accuracy of the exam goes down. While a single-question exam is the most accurate technique, some clients need to resolve more than one aspect of a case. In those situations, it is still not recommended to ask more than 3 relevant questions in a single exam, and these questions must be related to one another. Examiners can not "mix issues" in a polygraph exam. If you need to cover more than 3 relevant questions or need more than one issue covered, you will have to do more than one exam.
How many exams can one person take in a day ?
In polygraph there is a process called "habituation" which means that over a period of time that person's reactions to questions will be reduced. At some point those reactions will drop below a level that can be analyzed. When that point is reached, further testing will not produce results of any kind and testing must be resumed at some later date. How long it takes to reach this point, however, is different for everyone and is dependent on many factors. If the examinee is well-rested and free of drugs and alcohol, he or she may be able to produce adequate charts through 3 or 4 exams. Some individuals will stop producing adequate charts after only one exam. So the answer to this question is, it depends. It is our recommendation that you should not administer more than 2 exams on one person on the same day. Keep in mind that each exam will require the examiner to run 2 to 6 charts, and that each exam can take several hours.
Who makes up the test questions ?
There are many rules for question design (see below). Your examiner should work with you to develop the best possible questions to resolve a particular situation. Each exam is custom-made.
What are the rules for polygraph questions ?
- All polygraph questions must be answered with a "yes" or "no." Narrative answers are not permitted.
- Questions can not be subjective or ambiguous. Each question must be interpreted the same way by any person who hears it. When in doubt, specific words or phrases can be defined and agreed-upon before the exam.
- Hypothetical questions are not permitted.
- Questions about opinions, emotions, feelings, or the future can not be used. Examiners will not ask if someone loves you.
- Compound (multi-part) questions are not generally used.
- Questions about lying are not generally used. Polygraph questions are asked in the most direct way possible. For example, we would ask "Did you steal the missing wallet?" and not "Are you lying about stealing the missing wallet?"
- Questions in the same exam must be related to one another. Examiners can not mix issues in a test. For example, we can not ask questions about "stealing" and "using drugs" in the same exam. Each new issue requires a separate exam.
What do I look for when hiring an examiner ?
Please visit our Selecting an Examiner
page for details on this topic.
Where can I find a qualified polygraph examiner ?
Our sponsor, the Global Polygraph Network, has hundreds of testing locations worldwide staffed by experienced examiners. To find a qualified examiner near you, click HERE
Why does it take up to 3 hours to ask just one questions ?
Polygraph is a diagnostic procedure and in reality is nothing like you might see on television. The exam begins with a collection of background information, both from the client and from the examinee. The examiner must then explain the procedure and psychological principles being used. An interview then follows where the case information is discussed in detail. After this, the examiner designs the test questions and reviews those questions with the examinee. Next, the actual testing phase begins where the examinee is attached to the polygraph and is asked the questions that were reviewed. This exam may be done from 3 to 6 separate times. After all the exams are completed, the examiner must review all the materials and render a decision. In some cases a post-test interview is also conducted by the examiner to discuss the results.
Why does a polygraph exam cost so much ?
Polygraph examiners are highly trained professionals, most with college degrees, who provide a very specialized service. This service requires the examiner to purchase expensive equipment and pursue continuing education in order to maintain a high degree of proficiency. The process of asking "just one question" could take hours, due to the diagnostic process involved, so a single exam often takes an examiner an entire working day (including travel). In most cases, the polygraph is performed because there simply is no other reasonable way to get the desired information, such as when no evidence exists one way or the other, or when it is simply a "he-said-she-said" situation. For example, in a fidelity case a person might spend thousands of dollars on surveillance while the same information could be obtained for a fraction of the price with polygraph, resulting in thousands of dollars saved. The fees charged for polygraph testing are reasonable when considering the cost of training and equipment, degree of specialization and worldwide need for this unusual service.
Can someone else be in the room during the exam ?
No. In order to preserve a "sterile" environment, no one other than the examiner and examinee can be in the exam room during the procedure. Polygraph is a diagnostic procedure which can be adversely affected by distractions. In addition, it is typically easier for the examiner to obtain admissions (confessions) when no one else is in the room. The customer may request that the exam be audio or video taped (additional fees will apply), but not all examiners will permit this option.
Is it possible to "beat" a polygraph ?
The polygraph works by recording changes in a person's Sympathetic Nervous System, part of the Autonomic Nervous System, which operates independently of conscious thought. For example, your lungs and heart continue to operate even when you are asleep - you don't have to think about them. These systems can be consciously controlled only very slightly, and attempts to change these systems are usually picked up by the examiners, who are trained to identify such things. It is highly unlikely that someone can alter the outcome of a polygraph exam, but it is not impossible. A verified accuracy rate as high as 98% attests to this fact.
Most examiners are now using "countermeasures detection" equipment which easily identifies anyone attempting to use the techniques taught by some web sites and government agencies. unfortunately, many honest people are found "deceptive" to the test questions after attempting to use these techniques simply because they attempted to influence their test results. When an examiner discovers that the examinee is doing things to affect the charts, the result is either "deception indicated" or "inconclusive." In other words, a person will not pass a polygraph by using these techniques. In fact, recent research (2008-2009) has determined that in most cases when someone attempts to use the techniques taught on the internet to "beat" a polygraph, their test results actually GET WORSE (their scores indicate greater deception than if they had done nothing).
Use of certain drugs and medications can also affect the exam, but such use generally results in an "inconclusive" test. It is virtually impossible to change a result from "deceptive" to "truthful" through the use of drugs or medications prior to an exam. If drugs are suspected, a pre-test (or post-test) drug screening is advised.
Will an examiner come to my house to conduct the exam ?
Some examiners will be willing to conduct exams in a private home, but many will not. Since a very private setting is needed for the procedure, it is often best to rent a small office or meeting room for this purpose.
Are polygraph results admissible in court ?
While polygraph results are not per-se inadmissible in most courts, the final decision usually rests with the individual judge or arbitrator. Civil and family courts are more likely to admit polygraphic evidence than criminal courts. Clients must check with the specific jurisdiction to determine local admissibility standards. If you intend to use polygraph results as evidence, you should select an examiner who has testified and been qualified as an "expert." Some judges will require a "Daubert" hearing to determine the admissibility of scientific evidence on a case-by-case basis. Even though polygraph results are not always admitted in a court proceeding, this technology is often used outside of the courtroom, such as to dissuade a prosecutor from pursuing a weak case.
What is the minimum age for someone to take a polygraph ?
Anyone 18 years of age and older can legally consent to a polygraph exam. Under age 18 requires written permission from the parent or guardian. Most examiners will not test children under 12 years of age.
Can medications affect the test results ?
Yes. Any drug or medication that suppresses normal activity of the Central Nervous System (sedatives, anti-anxiety meds, blood pressure stabilizers, etc.) will reduce the strength of reactions found on the polygraph charts, resulting in a higher likelihood of inconclusive results. The medications will not change the outcome of an exam (ie. they will not make a deceptive person appear to be truthful) and only serve to reduce the odds of resolving the problem. It would be our suggestion to test any person who is using these types of drugs or medications on a computerized polygraph which is capable of greater sensitivity than the analog version.
What if the person taking the exam has a medical condition ?
A polygraph exam does not cause any direct injury to the person being tested. The only discomfort is a standard blood pressure cuff which goes on the arm (typically) and is inflated for less than five minutes at a time. There are increased stress levels during the testing process which should be considered. Some medical conditions are sensitive to increased stress levels, such as some heart conditions. Depending on the medical condition, most examiners would require an approval from the treating physician prior to conducting an exam on someone with such a condition.
Can a handicapped person take a polygraph ?
Depending on the type and severity of the handicap, most examiners can find a way to conduct the exam. For example, deaf persons can be tested by the use of flash cards or a signing interpreter. In general, the examinee must be able to sit very still for about 5 minutes at a time, so any disorder that creates involuntary movements would interfere with the data collection process.
Can a pregnant person take a polygraph ?
It does not affect the outcome of a polygraph exam to test a pregnant woman unless the fetus is making excessive movements or causing pain to the mother during the exam. Many examiners will not test a pregnant woman under any circumstances, but others are ok with testing after the first tri-mester. Some examiners will test only with a note from the woman's physician stating that there are no complications from the pregnancy and that the stress of taking a polygraph would not impact the health of the mother or fetus. Note: Most examiners in Texas are not permitted to test a pregnant person.
Will being nervous affect the test results ?
The polygraph instrument measures CHANGES in a person's physiology during the course of the test. Nervousness is a generalized condition which exists throughout the entire exam, not just on one or two questions. Because nervousness exists during the entire test process, it will not affect the test score. Extreme nervousness, however, may cause a person to fidget or not sit still during the exam, and this could distort the test enough so that the results can not be analyzed. In general, though, being nervous will not change a person's test results. Most people are nervous when doing anything new for the first time.
Is there a best time of day to have a polygraph exam administered ?
Yes. Since it is important that the person tested be capable of maximum reactions (for scoring purposes), that person should be well rested prior to the exam. In other words, testing done in the morning will be more productive than those done later in the day, and testing done in the evening significantly increases the risks of an inconclusive result. The person should also not be tested right after an argument, interrogation or long day of work if possible.
Is it better to use a computerized polygraph rather than an analog polygraph ?
Analog polygraph equipment has been around for 60 years and is still widely used today. Analog equipment records information on a moving roll of chart paper using ink or thermal paper. More recently, computerized (digital) polygraphs were developed which record data directly to a computer program. These new systems include complicated chart analysis formulas and inkless display systems (on a computer screen rather than a roll of chart paper). Scoring of the charts is done the same for both systems, but the computerized system has built-in aids for the examiner and prevents equipment failures that are sometimes experienced with mechanical equipment. However, a competent and qualified examiner can be equally effective with either system.
Are polygraphs on TV talk shows and reality shows for real?
Sometimes yes, but most often no. When a highly qualified examiner conducts polygraphs for television, the exams are done off-camera before the show and can take several hours each. The examiner may then re-enact a small portion of the exam for the audience, so what you see is never an actual polygraph. Unfortunately, most so-called examiners working for television provide 20 minute exams, ask a dozen questions, and give results that are no more accurate than flipping a coin. Any producer who actually cares about the quality of the test and the results will allow the examiner to spend sufficient time with the person tested (up to several hours) and will limit the number of questions to three or less (per exam) to maintain overall accuracy. Most producers are only interested in getting a test done in the shortest amount of time and the smallest budget possible. Don't believe everything you see on television.
Is the test confidential ?
If this exam is being conducted at the request of an attorney, any information obtained during the course of this examination is covered under attorney privilege and can not be disclosed to anyone outside of this relationship. If privilege is not attached, any information obtained during the course of this examination will only be disclosed to the client, or to anyone authorized by the client, with the following exception. Under U.S. Title 18, U.S.C. 4 (Misprision of Felony) if the examinee admits to having committed a felony, examiners are required to report this information to appropriate authorities. Also, in some states that require a polygraph license, an examination failure to questions about involvement in a serious crime must also be reported.
Can someone in prison be tested privately ?
Yes. However, testing in prisons requires making special arrangements, usually through an attorney, to insure that an adequate exam room is provided which is free from interfering noises and distractions. You should also discuss test duration with the examiner so that sufficient time is allotted for the test.
Can polygraph be done over the phone ?
Absolutely not. Polygraph is done with an examiner face-to-face and involves equipment that must be physically attached to the person being tested. There is a technology that uses voice analysis, but this technology is not considered reliable. 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 - such as the voice - is to remove a great deal of information the examiner could have used. Voice Stress Analysis (VSA) only measures one aspect of physiology. Even if we accept that VSA can detect stress - which recent research has refuted - that is still not an indicator of deception.
How can I become a polygraph examiner?
First you must complete an accredited polygraph training program. After graduating, you must gain experience by working for an established polygraph company or government agency. Once you have achieved some experience, under supervision, and meet any other licensing requirements (varies by state) you will be able to provide polygraph services on your own. Click HERE
for a list of accredited training schools.