Polygraph

A polygraph test simultaneously records changes in blood pressure, heartbeat, pulse rate, muscle movements, as well as perspiration and respiration levels.

Used as a lie detector by investigators and crime enforcement officers, it is increasingly being employed to pre-screen candidates for sensitive assignments or to test for substance abuse.

With accuracy rates of up to 95%, some believe that only sociopaths, psychopaths, or simply incredibly good liars who can tell a lie 'honestly' will slip through the polygraph net. Inconclusive tests are very rare indeed. However, while polygraph tests are seen as indicators of honesty (or otherwise), results are always used in conjunction with strong supporting evidence.

The key to accuracy in polygraph testing lies in the quality of the examiners. In fact, the most important part of the test - which typically lasts two or three hours - is the preparation stage.

The examiner first endeavours to put the interviewee at ease, and will then ask a series of questions to which the answer is known. The recorded responses to these questions act as a baseline for the interrogation that follows.

Examinations are totally painless, with the interviewee hooked up to two pneumograph tubes - one attached to the upper chest, and the other to the abdomen. In addition, metal plates are attached to the ring and index fingers, and a blood pressure cuff is wrapped around the upper arm.

To maintain the integrity of the test it is important that the examinee is honest about bothersome questions so that the examiner can avoid triggering unnecessary stress responses. For example, if asked about drinking habits, it's perfectly plausible for an examinee who is only a social drinker to become nervous if his or her parents were habitual drunks and the question triggers bad memories.

Polygraph results can be released only to authorised organisations or individuals - usually the government agency, company or person requesting the examination. They are not admissible as evidence in UK courts.

GSS is among only a small number of commercial practitioners accredited to provide polygraph testing in Europe. Our examiners are all members of the American Association of Polygraph Examiners, the world's leading authority.

We are often required to travel with our polygraph equipment and have successfully conducted tests in the most hostile conditions. As well, we are frequently called on to present our findings as expert witnesses in Court.

Should you wish to know more about our Polygraph test services, an initial consultation implies no commitment to proceed and our discretion is assured.