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Police Use of the Polygraph in Criminal Investigations

NCJ Number
96754
Journal
Canadian Journal of Criminology Volume: 27 Issue: 1 Dated: (January 1985) Pages: 43-66
Author(s)
F J Desroches; A S Thomas
Date Published
1985
Length
23 pages
Annotation
This article considers the function of the polygraph, discusses its reliability and validity, and describes the polygraph examination.
Abstract
The polygraph examination is composed of a number of procedures; the examiner must become familiar with the facts of the case, conduct a pretest interview, administer the test, and interpret the results. Following the administration of the test, the examiner compares and quantitatively scores each graph, searches for consistency in the subject's physiological responses, and determines whether he/she has been truthful or deceptive or whether the test is inconclusive. Once the examiner has made his/her determination, he/she informs the subject of the results. Findings from a sample of cases indicate that slightly more than 50 percent of the subjects were judged to be truthful, slightly less than 40 percent were thought to be deceptive, and 10 percent were classified as inconclusive. Approximately one-half of all inconclusive cases can be resolved upon reexamination. Although polygraph results are not used in criminal courts in Canada, the police have found the polygraph an effective tool in eliminating subjects, determining whether a crime has been committed, obtaining admissions of guilt, and gathering additional information. The polygraph is not infallible; it is subject to both misuse and abuse. However, the polygraph has nonetheless proven helpful in determining the truth in criminal investigations. Further, its contribution is particularly unique, because it often successfully resolves a crime when other investigative techniques have failed. Eighteen references are included.

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