Extending Daubert beyond scientific expert testimony

VOLUME 30 , NUMBER 6 June 1999

JUDICIAL NOTEBOOK

Technical and other specialized knowledge must be reliable to be admissible

By Richard L. Wiener, MLS, PhD
Saint Louis University

In Daubert v. Merrell Dow Pharmaceuticals, Inc., 509 U.S. 579 (1993) the U.S. Supreme Court made trial judges "gatekeepers" and provided them with broad discretion to determine whether or not scientific expert testimony was reliable enough to be admissible. The Daubert court offered trial judges specific, but not exhaustive factors to consider: whether the scientific knowledge can be (and has been) tested, whether it has been subjected to peer review, the size of the known error rate for findings, and whether the knowledge enjoys widespread acceptance in the scientific community (Daubert 1994, p. 593-594).

The ruling left unresolved the reach of the gatekeeping function that it so carefully described. Did the justices expect the ruling to apply to expert testimony in applied science, technology and other areas of specialized knowledge? This issue was recently decided by the U.S. Supreme Court in Kumho Tire, Inc. v. Carmichael, 119 S.Ct.1167 (1999).

Background on the case

In the summer of 1993, Carmichael's minivan suffered a blowout of the right rear tire as the plaintiff drove himself and several passengers to their destination. One of the passengers died of injuries sustained in the accident that followed and others were severely hurt. Carmichael and family brought suit against Kumho Tire, which manufactured the tire that caused the accident. An expert witness, provided a deposition in which he explained that a tire defect was likely responsible for the blowout. At trial, the expert would have testified about the observational methodology that he used to determine that the tire showed no signs of "overdeflection" (i.e., being driven while underinflated or overloaded with freight). Applying the Daubert factors, the trial judge excluded the tire expert's testimony because it failed to meet an adequate reliability standard (Carmichael v. Samyang Tires, Inc., Civ. Action No. 93-0860-CB-S, S.D. Ala., 1996). The Eleventh Circuit reversed holding that the Daubert standard and factors did not apply because the expert testimony did not rely upon "the application of scientific principles," Carmichael v. Samyang Tire, Inc., 131 F.3d 1435-1436 (1997).

Upon appeal, the U.S. Supreme Court ruled that the trial judge was correct in applying the Daubert principles. In accordance with Federal Rule of Evidence 702, a trial judge must determine whether expert testimony that "reflects scientific, technical or other specialized knowledge" has a "reliable basis in the knowledge and experience of [the relevant] discipline" (Kumho, p. 1174). In other words, Justice Breyer's majority opinion extended the reach of Daubert to include specialized testimony that is not purely scientific. Justice Breyer went on to write that the trial judge may apply the Daubert factors if they are appropriate to the testimony under consideration but that the trial judge has "considerable leeway" to determine the reliability of expert evidence. The Supreme Court supported the trial judge who concluded that the expert's methodology failed to "satisfy either Daubert's factors or any other set of reasonable reliability criteria" (Kumho, p. 1179).

Implications for psychology

This holding has important implications for psychological testimony that is based upon the professional work of forensic psychologists acting as mental health practitioners. It grants trial judges who evaluate the admissibility of assessment evidence broad latitude in determining whether the evidence is reliable and what factors to consider in making that determination.

For example, in a case in which an expert evaluates an alleged rape victim and could either testify about the presence (for the prosecution) or absence (for the defense) of rape-trauma stress syndrome, the trial judge appears to have discretion to decide whether to apply the Daubert factors to evaluate the reliability of the expert testimony or to use some other set of reasonable criteria (David E. Rovella, "Kumho" could affect criminal cases, Nat'L. L. J., April 12, 1999).

There are other psychological state testimonies that provide the same leeway for trial judges in assessing admissibility. From a practicing psychologist's perspective, Kuhmo makes it important to defend the reliability of the testimony either with the application of the Daubert factors or with another reasonable set of criteria.

It is too early too tell whether Kuhmo will increase or decrease the admissibility of psychological testimony, but it is clear that it provides the trial judge very broad discretion. From the point of view of applied researchers, the problem of understanding how factors outside the Daubert analysis can and will be used to evaluate the reliability becomes an interesting research problem with important practical significance.

"Judical notebook" is an effort by the Courtwatch Committee of APA's Div. 9, the Society for the Psychological Study of Social Issues, to encourage involvement by psychologists in judicial decision-making.

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