Polygraph Testing

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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 test accuracy 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 is 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, D.C.: U.S. Department of Defense, 1984. Complete reprints may be purchased from: APA Publications, P.O. Box 1061, Severna Park, Maryland 21146-8061.

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