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The polygraph (lie detector) is a scientific instrument capable of simultaneously recording changes in several physiological variables such as blood pressure, pulse rate, respiration, electrodermal activity, and others, while the subject is asked a series of questions pertaining to a specific issue under investigation. The charts (polygrams) generated during the polygraph examination are interpreted by a polygraph examiner. The literal meaning of the word “polygraph” is “many writings”.

The polygraph was invented in 1921 by John Augustus Larson (1892-1965) a medical student at the University of California and a police officer of the Berkeley Police Department (Berkeley, California, USA). Dr. Larson, born in Shelbourne, Nova Scotia, Canada, was the first to simultaneously record more than one physiological parameter with the purpose of detecting deception. Dr. Larson developed and utilized the continuous method of concurrently registering changes in pulse rate, blood pressure, and respiration. In conjunction with his polygraph, Dr. Larson used a test/a scientific procedure originated by Dr. William Moulton Marston (1893-1947) in the Harvard Psychological Laboratory in 1915 and applied by him to various fields of investigation during World War I. Dr. Larson modified Dr. Marston’s procedure and applied it to the police procedure at the Berkeley Police Department beginning in 1921.

No. Nervousness does not interfere with the polygraph test. It is expected that every individual undergoing a polygraph examination will be nervous whether he/she intends to answer questions truthfully or not. Typically, an examinee remains nervous throughout the entire testing process not during one individual question. A polygraph examiner will look for action-specific responses over and above the examinee’s heightened level of nervousness or anxiety. If nerves affected the result of a polygraph test, then no one would ever pass a polygraph test.

The polygraph is considered officially one of the greatest inventions of all time. For example, the polygraph (lie detector), invented by John A. Larson of the U.S. in 1921, is included in the Encyclopaedia Britannica Almanac 2003’s list of 325 greatest inventions. Originally published in 1768, the Encyclopaedia Britannica is the oldest continuously published English-language encyclopedia and one of the world’s most trusted sources of information.

Leonarde Keeler (1903-1949), born in North Berkeley, California, USA, is the most prominent polygraph examiner of all times. Having conducted over 30,000 polygraph examinations, Leonarde Keeler is one of the world’s foremost scientific criminologists, whose contribution to the stature of the field of lie detection is merely immeasurable and invaluable. In 1925, Leonarde Keeler (a Stanford University psychology major working at the Berkeley Police Department), developed two significant improvements to Larson’s polygraph: a metal bellows (tambour) to better record changes in blood pressure, pulse and respiration patterns, and a kymograph, which allowed chart paper to be pulled under the recording pens at a constant speed. In 1936, Keeler added a third physiological component to his polygraph – the Psychogalvanometer – a device for measuring changes in a person’s skin resistance. This version of Keeler’s polygraph was the prototype of the modern polygraph, and Keeler himself is therefore considered the “father of modern polygraph”.

Lafayette Instrument Company, located in Lafayette, Indiana, USA, is the unconditional global leader in the manufacture and sale of polygraphs. Lafayette Instrument Company, founded in 1947 by Max Wastl (1915-1990), has been manufacturing polygraphs since the 1950’s. Under the stewardship of the company’s current owners Roger B. McClellan, Christopher L. Fausett and Terrance G. Echard, Lafayette Instrument Company has achieved a global polygraph market share of approximately 92 percent.

Depending upon your location in the world, you can purchase a polygraph either from Lafayette Instrument Company directly or from Lafayette Instrument Company’s exclusive representative in your country. If you are located in European Union and in some other European countries (39 countries), you can purchase polygraphs from Argo-A Security EU (Košice, Slovak Republic) – Argo-A Security’s and Chicago Polygraph Institute’s representative.

Approved ILPE polygraph instrumentation includes polygraphs and polygraph accessories manufactured by Lafayette Instrument Company. The polygraph exists to protect the public by verifying the truth and determining deception. It is ILPE’s concrete position that we can succeed in protecting the public by utilizing only the most advanced polygraph instrumentation, as in our profession there is no margin for error. The ever-objective market forces indicate that Lafayette Instrument Company manufactures precisely the superior polygraph instrumentation the polygraph market values the most. Market forces also indicate that Lafayette Instrument Company’s global hegemony in the manufacture and sale of polygraph instrumentation is due to the competitive advantage of its products and services. It is apparent to the ILPE that in countries where a polygraph purchasing decision is based on objectivity and not political, patriotic, corrupt, nepotistic or other motives, the overwhelming majority of polygraph examiners prefers Lafayette Instrument Company polygraph instrumentation.

The list of ILPE-approved polygraph schools includes all twenty (20) APA accredited polygraph schools and Chicago Polygraph Institute (CPI) – an ILPE accredited polygraph school from Indiana, USA, represented in European Union and some other European countries (39 countries) by Argo-A Security EU, located in Košice, Slovak Republic.

In order to become a polygraph examiner you must graduate from an ILPE or an APA accredited polygraph school. To be accepted by these schools, applicants must meet strict education, ethics, and moral requirements. Moreover, they must be of excellent character and reputation, and have no felony or misdemeanor convictions.

Membership in the International League of Polygraph Examiners is a privilege. Only graduates of ILPE and APA accredited polygraph schools are eligible for membership in the ILPE. In addition, they must utilize ILPE and/or APA approved polygraph instrumentation meeting strict international quality standards. If you meet the above requirements, please feel welcome to contact us to apply for ILPE membership.

Polygraph examinations are conducted by polygraph examiners in the private, law enforcement and government sectors in approximately 100 countries. The polygraph is most actively used in the United States of America, Mexico, Israel, Russia, South Africa, Ukraine, Colombia, Japan, South Korea, Singapore, Canada, India, and Poland to name a few. The USA leads the list with millions of polygraph examinations administered on an annual basis. The list of well known polygraph users in the USA includes: Department of Defense and its many investigative agencies of the Army, Navy, Marines and Air Force, National Security Agency (NSA), Central Intelligence Agency (CIA), United States Secret Service, Federal, Bureau of Investigation (FBI), Internal Revenue Service (IRS), Department of Energy, Drug Enforcement Administration (DEA) and numerous other intelligence and federal law enforcement agencies. The polygraph is also used by state and local law enforcement agencies, U.S. and district attorney offices, public defenders, lawyers, parole and probation departments, public and private companies.

Recent research reveals that the accuracy of the new computerized polygraph system is close to 100 percent. In the past 75 years, over 250 studies have been conducted on the validity, accuracy and reliability of polygraph testing (American Polygraph Association 1996 Polygraph Issues & Answers). Based on twelve separate studies involving 2174 real cases since 1980, evidence suggests that qualified field polygraph examiners are 98 percent accurate in their overall decisions (Norman Ansley, “The validity and reliability of polygraph decisions in real cases”, Polygraph, v.19, 1990). Research clearly indicates that when administered by a competent polygraph examiner, the polygraph test is the most accurate means available to determine truth and deception.

Polygraph examination results are admissible in court in some countries, for example, in Japan, India, and USA. In the United States of America, most states permit polygraph examination results to be used as evidence where parties have agreed to their admissibility before the examination is given, under the terms of a stipulation.

The easiest way to make sure you are being tested by a qualified polygraph examiner is to ask if he or she is a member of the International League of Polygraph Examiners and/or the American Polygraph Association. We recommend that you contact the ILPE or APA to confirm your polygraph examiner’s membership.

It is important you choose a polygraph examiner who has been professionally trained, accredited, and certified. Every qualified examiner must reach certain competencies before certification(s) can be awarded. It is important to ensure that the polygraph examiner has attended an ILPE or an APA accredited polygraph school as deemed by the ILPE and the APA. Beware of unethical individuals who represent themselves as qualified polygraph examiners when, in fact, they do not have formal training or qualifications. A charlatan will often charge you less for his/her services; however, you should always be skeptical of his/her polygraph examination results.

Depending on the complexity of the case and the number of issues being tested a polygraph examination generally takes 2-3 hours

A professional polygraph examination consists of three phases: the pretest interview, the collection of charts, and the analysis of the polygraph charts. The average polygraph test will generally last 2-3 hours from beginning to end. The longest phase of the polygraph examination will be the pretest interview, which normally lasts 45-90 minutes. In the pretest interview phase, the polygraph examiner will complete the required paperwork and discuss the test questions so that the examinee fully understands each question in advance of taking the polygraph examination. The examiner will also explain the polygraph testing process and answer any questions or concerns. The collection of charts phase takes place in a quiet room with no one but the polygraph examiner and examinee present to prevent distracting the examinee. The polygraph examiner will attach sensors to the subject and ask “yes” or “no” questions that have previously been discussed. Data is collected from the sensors in the form of polygraph charts. In the last phase, the examiner will analyze the charts and render an opinion as to the truthfulness of the person taking the test.