In 1993, the United States Supreme Court established a new standard for the admissibility of scientific evidence in federal courts under Federal Rule of Evidence 702. The Court's decision in Daubert v. Merrell Dow Pharmaceuticals, Inc.(1) required federal courts to alter the manner in which they evaluated the admissibility of scientific evidence, including the results of polygraph or "lie-detector" tests. In the almost five years since Daubert was decided, the decision has been applied to polygraph tests on a number of occasions with courts' decisions on the admissibility of polygraph results varying from admissible(2) to inadmissible(3) to admissible under certain conditions.(4) In addition to the Daubert standard, scientific evidence must also clear the hurdle imposed by Federal Rule of Evidence 403. Further complicating the admissibility issue are two recent Supreme Court decisions: General Electric, Co. v. Joiner(5) and United States v. Scheffer.(6)
This Note argues that the results of polygraph examinations, as they are conducted today, should not be admissible as evidence in federal courts.(7) Part I of this Note examines the admissibility analysis laid down by the Supreme Court in Daubert. Part II describes polygraph examinations and the science behind them. Part III analyzes polygraph examinations under the Daubert factors. Part IV addresses the admissibility of polygraph examinations under Federal Rule of Evidence 403. Part V focuses on recent developments in the law since Daubert involving the evidentiary use of polygraph tests. Part VI explores two other related issues: the admissibility of polygraph results under Federal Rule of Evidence 608, and the admissibility of polygraph evidence when stipulated to by both parties. Finally, Part VII offers conclusions concerning polygraph evidence in federal courts.
I. DAUBERT AND SCIENTIFIC EVIDENCE
Daubert v. Merrell Dow Pharmaceuticals, Inc. was a case brought by two children and their parents against the manufacturer of a drug known as Bendectin.(8) The plaintiffs alleged that Bendectin, given to pregnant women to control nausea, was the cause of the children's birth defects.(9) As part of their case, plaintiffs attempted to introduce expert scientific evidence based on various studies which suggested that Bendectin could cause birth defects.(10)
The district court granted the defendant's motion for summary judgment because it found that plaintiff's scientific evidence did not reach the proper level of general acceptance in the relevant scientific community.(11) The court of appeals affirmed on the same basis.(12)
Both the district court and court of appeals based their decisions on Frye v. United States,(13) in which the D.C. Circuit held that scientific evidence was "inadmissible unless the technique is `generally accepted' as reliable in the relevant scientific community."(14) Frye's "generally accepted" test continued to be the prevailing standard for scientific evidence until the Supreme Court decided Daubert. Prior to addressing the proper admissibility standard of scientific evidence, the Supreme Court first had to address Frye and its proper place under the Federal Rules of Evidence. The Supreme Court held that the Frye test had been superseded by the adoption of the Federal Rules of Evidence, specifically Rule 702.(15)
In interpreting Rule 702, the Court held that an expert's testimony must be grounded in "scientific knowledge."(16) The Court stated that "scientific" implied a basis in the methods and procedures of science, while "knowledge" represented more than "subjective belief or unsupported speculation."(17) The second requirement in addition to "scientific knowledge" is that the evidence "assist the trier of fact."(18) The Court noted that this aspect of Rule 702 was basically a relevance requirement and stated, "Rule 702's `helpfulness' standard requires a valid scientific connection to the pertinent inquiry as a precondition to admissibility. …