Unsuitable for a polygraph test

Examiners should not conduct polygraph examinations on individuals determined to be unsuitable. When available, examiners should consider psychological diagnostic information. Individuals deemed unsuitable for polygraph testing should not be tested until the identified conditions have improved, and when the individual is able to adequately attend to the examination context. Conditions that should preclude an examinee from suitability for polygraph testing include the following:

Psychosis

Mean Age Equivalence (MAE)

Severe mental retardation

DSM Axis V Global Assessment of Functioning (GAF)

Special populations.

Medical

Precluded by law or regulations

Medications

Requirements for a valid test

Minimum Requirements for a Valid Polygraph Examination: There are certain prerequisites that should be kept in mind when determining whether a polygraph examination is valid.

  • The polygraph examiner must have been trained at a polygraph training facility accredited by the APA. This implies adherence to a strict code of conduct and ethics.
  • The polygraph examiner must be a member in good standing at the relevant associations and federations.
  • The polygraph examiner must be experienced enough to be able to analyse the chart tracings or polygrams and such experience must have been gathered while working under supervision.
  • The polygraph examiner must be independent, impartial and objective.
  • The polygraph technique and test procedure must be explained to the examinee.
  • Polygrams or chart tracings must be assessed manually and computerised evaluationmay be used only for the purpose of quality control or to obtain other opinions.
  • The polygraph examiner must be able and willing to testify as an expert witness for HR or legal proceedings.
  • The examination must be done voluntarily and this must be stated in writing - by signing a consent form.
  • The examinee must be, as far as can be ascertained, free of serious illness.
  • The examinee should preferably, not have been subjected to accusatory interrogation prior to the examination.
  • The examinee must not be under the influence of alcohol or narcotics at the time of the examination.
  • The examinee must have had a reasonable amount of rest prior to the examination.
  • The examinee must have been prepared and notified in advance about the examination
  • The instrument must be in good working order and record at least three channels.
  • At a minimum, the device should record tracings for cardiovascular and breathing patterns as well as electrodermal skin responses.
  • An internationally accepted, valid questioning technique must be used.
  • All questions must be thoroughly reviewed with the examinee before the collection of charts takes place.
  • A minimum of three polygraph charts should be recorded during the chart collectiphase of the examination.
  • The environment in which the examination is administered should be conducive to proper polygraph testing, i.e. a quiet environment without serious visual or audio interference.

Accuracy and reliability

How it works

Over 75 years, there have been more than 250 studies on the accuracy of the Polygraph. The Department of Defence Polygraph Institute of the United States of America (DODPI) as well as the American Polygraph Association (APA) recently did a study of the accuracy of all other studies done. The average accuracy range was found to be in the region of 90-95%.Studies can be viewed at: www.polygraph.org/polygraph-validity-research

According to Dr David C. Raskin, the world-renowned expert and leading scientist in the field of polygraphy, the scientific data concerning the validity of the polygraph can be summarized as follows:

"High quality scientific research from the laboratory and the field converge on the conclusion that a properly conducted CQT (Comparison Question Test) is a highly accurate discriminator of truth tellers and deceivers. The research results converge on an accuracy estimate that exceeds 90 percent."

According to the American Polygraph Association (APA), 80 research projects, which included both laboratory and field studies, have been conducted and published since 1980 on the validity and reliability of polygraph testing. These projects involved approximately 6,300 polygraph examinations. Of the 23 field studies conducted, the accuracy of polygraph testing was estimated to be 95 percent.

Like any other diagnostic instrument that is used to measure human physiology for the purpose of evaluation and forming professional opinions thereupon, the polygraph instrument is not infallible. The relevant scientific community agrees, however, that polygraph examinations have a very high probative value in distinguishing truthful individuals from deceptive ones, and that no other alternative testing technique for truth verification and lie detection performs better.