FAQS
Answers to Common Questions About the Polygraph Testing Process
What is a polygraph?
The polygraph is a scientific instrument which records and displays physiological responses to test items. Modern instrumentation is computerized and includes specialized software to aid the examiner. The word polygraph comes from Greek words meaning “many writings.” It denotes the multiple tracings that polygraphs display. The word itself can be traced at least to mid-19th century scientific writings regarding a device for recording various channels of physiological activity for medical purposes.
Today polygraph almost always refers to the device used for veracity testing.
What does the polygraph record?
Today’s polygraph records five or more channels of physiological data. Two corrugated tubes are placed around the body, one just above the heart and the other over the stomach to detect motion associated with breathing. Changes in skin moisture are monitored with sensors placed on the fingers or palms. Pulse and relative blood pressure are detected using a standard blood pressure cuff placed on the arm.
Many instruments also record changes in blood vessel dilation using a finger sensor and all polygraphs now include sensors to detect body movement. Each component is very sensitive to bodily changes. From the beginning to the end of the test, a person’s body emits physiological data that will be later reviewed by the polygraph examiner to determine if the examinee was telling the truth.
Is the examination confidential?
Yes, the test is completely confidential. Disclosure of the results is limited to those listed in an agreement signed by the examinee and the examiner prior to the examination unless otherwise specified by law.
Can someone be forced to take a polygraph examination?
No. Polygraph testing requires the voluntary cooperation of the examinee as a matter of both law and practicality. Polygraph testing may be a requirement for certain opportunities (e.g., to secure a government security clearance, as a condition for probation, to become a sworn law enforcement officer, etc.) but an individual is not obligated to pursue opportunities that incur a polygraph requirement.
How long does a polygraph examination take?
Most polygraph examinations take between 90 and 120 minutes, the majority of which entails a standardized interview before the testing phase. Examinations may take longer when covering complex issues. Polygraph examinations taking less than an hour have been reported, though the shortest of examinations are often associated with unvalidated or invalid procedures.
How many questions are on the test?
It depends on the type of test being given; the science associated with a particular technique will determine the number of questions which are allowed. Generally, examiners use between two and four questions about the test issue along with a small number of other questions included for technical reasons for a total of about 10 – 12 test questions. Some techniques use a smaller number of questions, but those questions are repeated several times within each test so that the total number of question presentations is about 10 – 12. The test questions are based on the answers the examinee gives during the interview, and the final wording of the test questions are negotiated between the examiner and examinee prior to the testing phase. There are no surprise questions in modern polygraph techniques.
Can nervousness affect the test results?
Everyone who takes a polygraph examination is nervous. It is expected. As everyone knows, anxiety can elevate one’s heart rate, blood pressure and other physiological functions. During polygraph testing, however, this heightened state becomes the examinee’s normal pattern. Having a higher blood pressure does not cause a person to fail a polygraph examination. Examiners are only interested in changes to the person’s normal pattern. While examiners take steps to reduce the jitters most examinees experience, there is no evidence that anxiety itself causes truthful people to fail or deceptive people to pass polygraph testing.
What should I do to prepare for my upcoming polygraph?
Continue normal day-to-day activities. Do what you can to arrive for your examination without the distractions of fatigue, hunger, or discomfort. Continue to take your prescriptions according to your provider’s directions. Avoid excessive use of stimulants or unnecessary over-the-counter medications before the examination as they may cause the session to go significantly longer than normal. Set aside all other obligations and appointments for the time of your examination. Be prepared to work with the examiner to resolve the matter being tested.
Can anyone beat a polygraph examination?
It is true that all things made by man can be defeated. The biggest challenge for beating a polygraph, however, is that it entails a significant risk of detection which, in these days of sophisticated software and recording equipment, makes success far from certain. Indeed, trying to affect the results can make things worse. Recent scientific research offers little hope for people relying on websites and books on how to beat the polygraph, and there is some evidence that the use of these methods by truth-telling examinees reduces their chances of passing the test. For these reasons we discourage examinees from trying to affect their test results.
Are polygraph results admissible in US courts?
Sometimes. The polygraph can be admitted as evidence in a court proceeding in many jurisdictions when both the prosecution and defense stipulate or agree that it can be admitted. This is typically accomplished by reaching an agreement between the parties before thepolygraphtestisadministered. Inaddition,NewMexicoallowsthepolygraphtobeadmitted without the stipulation of the parties under certain circumstances. Finally, many jurisdictions permit a party to seek admissibility on a case-by-case basis.
How accurate is the polygraph?
There are several polygraph approaches and applications, and polygraph accuracy is not the same for all of them. In a 2003 meta-analysis conducted by the US National Research Council, median accuracy was placed between 85% and 90% for event-specific testing or testing on single issues. This estimate was based on a range of polygraph techniques, from the unvalidated to the experimental to the best available. Subsequent research that focused only on techniques that employed empirically derived practices converged on a decision accuracy near or slightly above 90%.
What are the advantages of using an APA member to conduct a polygraph examination?
Not all polygraph examiners are APA members, and it is important to know the difference. Those who wish to qualify as APA members must have successfully completed an accredited polygraph education program meeting rigorous APA requirements. As APA members they are also required to maintain their continuing education hours. Those who want to practice certain specialties have additional requirements. All APA members are bound by the APA Bylaws, Standards of Practice and Code of Ethics, and must use only evidence-based valid polygraph procedures. Members also benefit from APA’s peer-reviewed publication to keep them apprised of the latest developments in techniques, technologies, and best practices. The APA sponsors educational seminars as well as online professional development not available elsewhere which ensures its members have access to the best information for conducting valid and reliable polygraph examinations. The APA is the largest professional polygraph association in the world. It attracts examiners who are committed to delivering the best possible polygraph services. To repeat: Not all polygraph examiners are APA members, and it is important to know the difference.
