5.6.4.2 The Frye and Daubert Decisions

• Jurisdiction: Arizona

In Frye v. United States,^[27] the court held that it will go a long way in admitting expert testimony that is deduced from a well-recognized scientific principle or discovery. However, the court stated that the thing from which the deduction is made must be sufficiently established to have gained general acceptance in the particular field in which it belongs. Just when a scientific principle or discovery crosses the line between the experimental and demonstrable stages is difficult to define, but somewhere in this twilight zone the evidential force of the principle must be recognized. Frye and its “general acceptance” test remained the rule regarding the admission of expert testimony until it was superseded in federal court by the adoption of the Federal Rules of Evidence, and the holding in Daubert v. Merrell Dow Pharmaceuticals, Inc., discussed below, which interpreted the effect of the adoption of the Federal Rules of Evidence.

In Daubert v. Merrell Dow Pharmaceuticals, Inc.,^[28] the Supreme Court stated that the “general acceptance” rule of Frye would be at odds with the “liberal thrust” of the Federal Rules of Evidence and their general approach of relaxing traditional barriers to “opinion” testimony. Therefore, the Supreme Court held the Federal Rules of Evidence superseded Frye’s “general acceptance” test for admissibility of scientific evidence. Under the Federal Rules of Evidence, the trial judge must ensure that any and all scientific testimony or evidence admitted is not only relevant, but reliable. When faced with the proffer of expert scientific testimony, the trial judge must act as a “gatekeeper” to determine at the outset whether the expert is proposing to testify to scientific knowledge that will assist the trier of fact to understand or to...