Admissibility of statements or confessions made before or after polygraph tests

Last revised November 13, 2025

Polygraph tests are considered a useful investigative tool in criminal matters as statements made before or after a test is administered may be admissible in court even while test results are not.

However, the courts have made clear that polygraphs should be used cautiously by police; in some cases, the courts have refused to admit statements or confessions obtained after a polygraph as the test was determined to have had a coercive effect on the accused, rendering the confession involuntary. Whether a statement made after a polygraph is deemed admissible depends on a variety of factors, including whether an accused is under intense psychological pressure or is emotionally distressed. Generally, if the polygraph is used coercively, the statement will not be admitted.

Some cases where statements made after polygraphs were deemed inadmissible are:

• R v. Fowler, (1979) 23 Nfld. & P.E.I.R. 255  
• R v. Romansky, 1981 CanLII 3514
• R v. Aggek, 1991 CanLII 13893
• R v. Nugent, 1988 CanLII 157
• R v. Heinermann, 2003 CanLII 36326
• R v. MacNeil, 1993 CanLII 4449

However, use of a polygraph test does not automatically mean exclusion of statements made after the test. If the polygraph test is taken without inducements, threats, or any improper police conduct, the statements are considered voluntary and can likely be admitted, as seen in R v. Morrison [1982] B.C.D. Crim. Conv. 5400-04 (Co. Ct) and R v. Brooks, 1986 CanLII 1168 (BC CA). The admissibility of a confession or statement will depend on the usual rules of admissibility of evidence. This includes cases in which a subject voluntarily takes a polygraph test, fails the test, and then confesses.

Even if the police exaggerate accuracy, reliability, or importance of the polygraph test, a confession is not automatically rendered involuntary; however, these will be relevant factors to determine voluntariness. In R v. Oickle 2000 SCC 38, the court ruled the accused’s confession voluntary, even though the police failed to tell him that the results of the polygraph test were not admissible as evidence and exaggerated the test’s reliability. As the accused was not ‘overwhelmed’ by the results and the confession was not made until sometime after the test was administered, the confession was ruled voluntary.

Similarly, in R v. Barton 1993 CanLII 14705, the appeal court found that the accused’s statement to the polygraph operator was voluntary, noting that a polygraph test uses the same intrusive and psychological techniques as all police interrogations.

• The following should be established to have a confession obtained after a polygraph test successfully introduced in court:
• The accused signed a consent to take the polygraph test.  
• The accused was given the usual police and Charter of Rights warnings prior to the test being administered.
• The police offered the accused fresh access to counsel, as found necessary in R v Sinclair 2010 SCC 35 when embarking on a “non-routine” investigative procedure such as a polygraph test.  
• Counsel should find out whether the accused had a lawyer present when the test was administered.
• There were no threats, promises, or inducements made to the accused to obtain the statement or confession.
• There was no atmosphere of oppression or force used during administration of the test or when the statement was taken. 

This evidence should be given at trial in a voir dire.

See Admissibility of polygraphs in BC and Canadian courts for more information about admissibility of polygraph tests.