This is one of the most frequently asked questions, and the answer is “yes” and “no”. The U.S. Department of Justice says”Neither the United States Code nor the Federal Rules of Evidence have a specific provision concerning the admissibility of polygraph examination results.”
Although the general rule has for many years been that lie detector tests are not admissible as evidence, it has been ruled “that polygraph results are admissible (1) when the parties stipulate to admissibility in advance of the test; or (2) when the polygraph results are used to impeach or corroborate the testimony of a witness. In the latter circumstance, the party seeking to introduce the polygraph results must provide adequate notice to the opposing party; the opposing party must be given adequate opportunity to have its own polygraph expert administer a test covering substantially the same questions; and the evidence must be admissible under the rules governing corroboration or impeachment.”
Specifically in Ohio, State v. Souel (1978), 53 Ohio St. 2d 123 — Syllabus: “The results of a polygraphic examination are admissible in evidence in a criminal trial for purposes of corroboration or impeachment, provided that the following conditions are observed:”
(1) The prosecuting attorney, defendant and his counsel must sign a written stipulation providing for defendant’s submission to the test and for the subsequent admission at trial of the graphs and the examiner’s opinion thereon on behalf of either defendant or the state.”
(2) Notwithstanding the stipulation, the admissibility of the test results is subject to the discretion of the trial judge, and if the trial judge is not convinced that the examiner is qualified or that the test was conducted under proper conditions he may refuse to accept such evidence.”
(3) If the graphs and examiner’s opinion are offered in evidence the opposing party shall have the right to cross-examine the examiner respecting: “(a) the examiner’s qualifications and training; “(b) the conditions under which the test was administered; “(c) the limitations and possibilities for error in the technique of polygraphic interrogation; and “(d) at the discretion of the trial judge, any other matter deemed pertinent to the inquiry. ”
(4) If such evidence is admitted the trial judge should instruct the jury to the effect that the examiner’s testimony does not tend to prove or disprove any element of the crime with which a defendant is charged, and that it is for the jurors to determine what weight and effect such testimony should be given.”
So, ultimately, the court does have the discretion to decide on the admissibility of polygraph tests in specific instances, but they are not generally allowed under current rules of evidence.