Are lie detector tests admissible in court in Arizona?

In Arizona, polygraph results are not admissible unless the parties stipulate to their admissibility; even when the parties have stipulated their admission, their admission is subject to the discretion of the trial judge.



When Are Polygraph (Lie Detectors) Results Admissible?

Brief Synopsis: Polygraph (lie detector) results are admissible when both the prosecution and the defense stipulate to their admissibility at trial, a preliminary hearing or other hearing.

Generally speaking, polygraph test results are inadmissible in court, as they are not scientifically reliable enough for use when the stakes are so high as in court.

This is because it is well documented that certain people can pass the pass the test while lying and other who are telling the truth can fail the test. To appreciate this, one should understand that polygraph machines measure variations in one’s breathing, pulse, sweating, and blood pressure to allegedly detect someone lying. The polygraph machine operator also may be financially motivated to provide the sought-after result. Nonetheless, they indeed are accurate 60% to 90% of the time, but these percentages are not high enough to considered “generally accepted” as scientifically reliable under Daubert-Frye (Daubert v. Merrell Dow Pharmaceuticals, Inc. (9th Cir., 1995) 43 F.3d 1311 and Frye v. United States (D.C. Cir., 1923) 293 F. 1013.


Credit: Greg Hill & Associates

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