§ 24.08 POLYGRAPH EVIDENCE

• Jurisdiction: United States

§ 24.08. POLYGRAPH EVIDENCE

The admissibility of polygraph evidence remains controversial.¹⁵⁵ Different types of polygraph tests are used depending on the purpose of the examination.¹⁵⁶ The use of polygraph testing for pre-employment screening at one time was quite common. However, the Employee Polygraph Protection Act of 1988,¹⁵⁷ with limited exceptions, prohibits the use of polygraph tests for pre-employment screening or during the course of employment.

A different type of examination is used when the focus is a specific incident, criminal or otherwise. The most common test used in this context is the control (comparative) question technique.¹⁵⁸ There are several different versions of this test, as well as a number of methods for scoring the results: global evaluation, numerical scoring, and computerized scoring.

The National Academy of Sciences published a report on polygraph testing in 2002. The focus of the report was national security screening, not criminal investigations. Nevertheless, the report reviewed the research and concluded: "Nothwithstanding the limitations of the quality of the empirical research and the limited ability to generalize to real-world settings, we conclude that in populations of examinees such as those represented in the polygraph research literature, untrained in countermeasures, specific-incident polygraph test can discriminate lying from truth telling rates well above chance, through well below perfection.¹⁵⁹The report went on to recommend against the continued use polygraph testing in security screening.

In Frye v. United States,¹⁶⁰ decided in 1923, the D.C. Circuit rejected the results of a precursor of the modern polygraph. The court held that the polygraph had "not yet gained such standing [general acceptance] and scientific recognition among physiological and psychological authorities."¹⁶¹ A majority of states still follow the traditional rule, holding polygraph evidence per se inadmissible. This exclusionary rule extends to evidence that a person was willing to take, took, or refused to take an examination. A minority of jurisdictions admit polygraph results upon stipulation. A third group leaves the admissibility issue to the trial judge. At one time, most federal circuit courts followed the per se exclusion approach. However, the Daubert decision changed this result.¹⁶² Nevertheless, most federal trial courts exercise their discretion to exclude polygraph evidence.¹⁶³

Military Rule of Evidence 707 makes polygraph evidence inadmissible in court-martial proceedings. In United States v. Scheffer,¹⁶⁴ the Supreme Court held that this rule of per se...