What is a Polygraph?
The term "polygraph" or commonly known as a “Lie Detector” literally means "many writings." The name refers to the manner in which selected physiological activities are simultaneously recorded. Polygraph examiners may use conventional instruments, sometimes referred to as analog instruments, or computerized polygraph instruments.

It is important to understand what a polygraph examination entails. A polygraph instrument will collect physiological data from at least three systems in the human body. Convoluted rubber tubes that are placed over the examinee's chest and abdominal area will record respiratory activity. Two small metal plates, attached to the fingers, will record sweat gland activity, and a blood pressure cuff, or similar device will record cardiovascular activity.

A typical polygraph examination will include a period referred to as a pre-test, a chart collection phase and a test data analysis phase. In the pre-test, the polygraph examiner will complete required paperwork and talk with the examinee about the test. During this period, the examiner will discuss the questions to be asked and familiarize the examinee with the testing procedure. During the chart collection phase, the examiner will administer and collect a number of polygraph charts.

Following this, the examiner will analyze the charts and render an opinion as to the truthfulness of the person taking the test. The examiner, when appropriate, will offer the examinee an opportunity to explain physiological responses in relation to one or more questions asked during the test. It is important to note that a polygraph does not include the analysis of physiology associated with the voice. Instruments that claim to record voice stress are not polygraphs and have not been shown to have scientific support.

Who uses polygraphs examinations?
Three sectors of society use polygraph examinations for various reasons and purposes.

Private Sector
Individuals, Families, Therapists and Employers use polygraph examinations to verify statements and find out the truth on a variety of issues including infidelity, drug use, addictions, sex offenses, employee theft, criminal activities, abuse and all other matters.

Legal Community
Polygraph is used extensively by attorneys who wish to provide the best possible defense for their clients. Most attorneys will submit their own clients to the exam, while others will use the polygraph to verify statements made by witnesses and other parties to litigation. Now known as Psycho physiological Detection of Deception (PDD), an experienced examiner can provide evidence in connection with any type of criminal or civil matter. Our examiners have a great deal of experience working with attorneys, both in private and government practice, and have aided thousands of clients in preparing defenses that would otherwise have been unavailable to them.
With the recent establishment of polygraph standards by ASTM, polygraph has gained great strides in credibility with the scientific community. These standards, approved by a combined body of experts, now provide a template for the increased acceptability of polygraph results.

Contrary to popular belief, polygraph is not per-se inadmissible in court proceedings. Admissibility standards are different in each jurisdiction. Some jurisdictions allow polygraph evidence, either stipulated or un-stipulated, some prohibit polygraph evidence altogether, and many others allow the judge to decide admissibility on a case-by-case basis. The Daubert case is presently the standard for the admission of scientific evidence, which includes polygraph. In reality, most polygraph results are used outside of the courtroom in pre-trial negotiations, plea bargaining, sentence recommendations, and witness verification or impeachment. We also have experts on staff who can provide testimony regarding polygraphist evidence administered by other examiners, and who can provide testimony regarding scientific credibility of polygraph.

Law Enforcement, Federal Agencies, Military and Government
Local Police, U.S. Military Branches and Government Agencies such as the FBI, CIA, NSA and Department of Defense all use polygraph examinations for applicant screenings, criminal investigations and matters of national security.

How accurate is the polygraph?
U.S. Government studies have concluded that the single-issue (one question) polygraph exam, conducted properly by a qualified examiner, is 87 to 95 percent accurate.  It is the most accurate tool available today for determining truth or deception.  Accuracy of the multi-question exam drops to around 80 percent due to a number of psychological factors.  These statistics do not include "inconclusive" results in which no opinion can be made from the polygraph charts, which happens about 20% of the time.

Why do Critics Figures Vary?
One of the problems in discussing accuracy figures and the differences between the statistics quoted by proponents and opponents of the polygraph technique is the way that the figures are calculated. At the risk of over simplification, critics, who often don't understand polygraph testing, classify inconclusive test results as errors. In the real life setting an inconclusive result simply means that the examiner is unable to render a definite diagnosis. In such cases a second examination is usually conducted at a later date.

To illustrate how the inclusion of inconclusive test results can distort accuracy figures, consider the following example: If 10 polygraph examinations are administered and the examiner is correct in 7 decisions, wrong in 1 and has 2 inconclusive test results, we calculate the accuracy rate as 87.5% (8 definitive results, 7 of which were correct.) Critics of the polygraph technique would calculate the accuracy rate in this example as 70%, (10 examinations with 7 correct decisions.) Since those who use polygraph testing do not consider inconclusive test results as negative, and do not hold them against the examinee, to consider them as errors is clearly misleading and certainly skews the figures.

Pre-employment Test Accuracy - To date, there has been only a limited number of research projects on the accuracy of polygraph testing in the pre-employment context, primarily because of the difficulty in establishing ground truth. However, since the same physiological measures are recorded and the same basic psychological principles may apply in both the specific issue and pre-employment examinations, there in no reason to believe that there is a substantial decrease in the accuracy rate for the pre-employment circumstance. The few studies that have been conducted on pre-employment testing support this contention.

While the polygraph technique is not infallible, research clearly indicates that when administered by a competent examiner, the polygraph test is one of the most accurate means available to determine truth and deception.

For an excellent review of the research involving validity and reliability, including pre-employment screening, see: The Accuracy and Utility; of Polygraph Testing. (1984) Washington, DC: U.S. Department of Defense, 1984. Complete reprints may be purchased from the APA National Office.

Polygraph Screening in Police Agencies - The Employee Polygraph Protection Act of 1988 (EPPA) prohibits most private employers from using polygraph testing to screen applicants for employment. It does not affect public employers such as police agencies or other governmental institutions. In the testimony regarding EPPA it became clear that there were no current and reliable data on a variety of important issues about police applicant screening, although polygraph testing had reportedly been used for that purpose since at least the early 1950's. In recognition of this gap, the APA Research Center at Michigan State University embarked on a survey of police executives in the U.S. to determine the extent of, and conditions in which, polygraph testing is being used for pre-employment screening The survey population included 699 of the largest police agencies in the United States, excluding federal agencies, and produced usable returns from 626 agencies, a response rate of 90%. The major results of the survey showed the following:

 Among the respondents, 62% had an active polygraph screening program, 31% did not and 7% had discontinued polygraph screening, usually because of prohibitive legislation. These results make it clear that a great majority of our largest police agencies do have a polygraph screening program in effect. These agencies employ, on average, 447 officers and service a population averaging 522,000 citizens. They primarily use the polygraph to screen applicants for sworn positions, although 54% also screen persons interested in non-sworn positions. Approximately 25% of the persons tested are disqualified from police employment based on the information developed during polygraph testing which, by the way, is used both to verify information provided in an application form and to develop information that cannot be gotten by other means. Only a very small proportion (2%) of agencies uses polygraph testing as a substitute for a background investigation. A rank ordered listing of topics covered during polygraph testing revealed that investigation of illegal drug usage, employment related dishonesty, and involvement in felonies are the most important.

When asked to indicate what their reasons were for using polygraph screening, the great majority of the agencies indicated that it reveals information that cannot be obtained by other selection methods. Closely following this item in order, was that polygraph testing makes it easier to establish background information, that it deters undesirable applicants, and that it is faster than other methods of selection. The three leading benefits of polygraph screening were that applications were more honestly completed; that higher quality employees were hired; and that there were fewer undesirable employees. Over 90% of these agencies expressed either moderate or high confidence in their polygraph screening program and 80% of them reported that in their experience the accuracy of the testing ranged between 86%-100%. The only procedure that was considered to be as useful as polygraph screening was a background investigation; all others, including written psychological tests, psychological or psychiatric interviews, personal interviews, and interviews by a selection board were judged to be less useful. Finally, this survey also showed that polygraph screening revealed applicant's involvement in serious, undetected criminality. For example, 9% of the agencies said that polygraph screening detected involvement by some applicants in unsolved homicides; 34% indicated some applicant involvement in forcible rape; and 38% showed some applicant participation in armed robberies. Other serious, unsolved crimes, such as burglary, arson and drug offenses were also revealed by polygraph screening.

What if the person 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 person fail a polygraph because of high blood pressure or nervousness?
No. Polygraph is not designed to record or measure nervousness. While a person's heart beat and respiration rate may increase when he or she is nervous, a qualified examiner understands this, and will take it into consideration when evaluating an examinee's response. Unlike general nervous tension, an examinee's reaction to deceptive responses is highly specific. An examiner mitigates a nervous response by reviewing the questions with the examinee and through an acquaintance or “practice test” prior to the exam.

Can someone beat the test?
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 it. 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 95% attests to this fact.

Is the polygraph admissible in court?
Federal courts have ruled that polygraph is NOT per-se inadmissible in a court procedure, but that it may be considered when standard rules of scientific evidence have been met. In other words, applicants must apply to the judge for admissibility under the "Daubert" standard of evidence on a case-by-case basis. Individual judges can still decline to accept polygraph results, however. Each jurisdiction must be checked to determine admissibility standards. One of the greatest fears keeping polygraph evidence out of courts is the fact that such evidence would carry greater weight than other equally-important evidence and would tend to sway a jury in one direction even though other evidence may point the other way. In most cases, polygraph evidence is used during pre-trial negotiations and plea bargain agreements rather than during the trial itself.

What does it mean when someone "fails" a polygraph?
When a polygraph examiner concludes that deception is indicated to one or more of the subject's answers, the subject is said to have "failed" the exam.  Deception is indicated when the person's autonomic nervous system displays a significant and repetitive "defensive" reaction to the relevant test question.  Although this reaction in itself is not a "lie," years of research have found that 90-95% of persons who display this reaction were either lying to the relevant questions or were withholding pertinent information relating to these question.  Frequently, an examiner will conclude only that "the subject can not be excluded as a suspect" when deceptive reactions are present.  It is important to note that some persons will "fail" a polygraph even though they are telling the literal truth but continue to hold back pertinent or incriminating information from the examiner.   We strongly suggest that no one make a life-altering decision based solely on the results of a "failed" polygraph test without the existence of additional evidence supporting this test result.

What Legislation dictates Polygraph?
Licensing - Currently there are 29 states and 3 counties which have laws requiring licensure or certification for polygraph examiners. Most laws require formal instruction, an internship training period and successful completion of a licensing examination. For example, the following are basic requirements for licensure in one state:

A person is qualified to receive a license as an examiner:
(a) Who establishes that he or she is a person of good moral character; and,

(b) Who has passed an examination conducted by the Licensing Committee, or under its supervision? To determine his or her competency to obtain a license to practice as an examiner and

(c) Who has conferred upon him or her an academic degree, at the baccalaureate level, from an accredited collect or university; and,

(d) Who has satisfactorily completed 6 months of study in the detection of deception, as prescribed by rule?

Are the results and information confidential?
Jack Trimarco & Associates Service adheres to very strict confidentiality and privacy standards. All information from an examination is kept strictly confidential and private.

FAQ’s provided by the American Polygraph Association