Reprinted with permission from Leader's Product Liability Law and Strategy, Vol. 17, No. 10, pp 1-3 (April, 1999). Copyright 1999 NLPIP Company.

Although many commentators have hailed the U.S. Supreme Court's decision in Kumho Tire Co. v. Carmichael, No. 97-1709 (March 23), as a victory for business, the real winner is the public, because Kumho will lead to more rational decision-making regarding who can testify as an expert.  In Kumho, a unanimous Supreme Court resolved a conflict among the appellate courts by holding that the Court's decision in Daubert v. Merrell Dow Pharmaceuticals Inc., 509 U.S. 579 (1993), applies to the testimony of all experts, regardless of whether that testimony is based on "scientific," "technical" or "other specialized" knowledge.  The decision is among the most important of the Court's term (the case attracted 19 briefs from amici), as it addresses an issue that arises in virtually all product liability litigation, and most civil litigation generally.  As Justice Antonin Scalia noted, Kumho and Daubert provide courts with a "reasonable means of excluding expertise that its fausse and science that is junky."

At issue in Kumho was whether Daubert applied to the testimony of Dennis Carlson, a purported expert about why tires fail, who claimed that his expertise was based primarily on his "experience" in that field.  The district court found that Mr. Carlson's testimony was not reliable by assessing it in light of the questions that Daubert identified as relevant to that inquiry, i.e., whether the "theory or technique can be (and has been) tested"; it "has been subjected to peer review and publication"; "in respect to the particular technique, there is a high 'known or potential rate of error'"; there are "standards controlling the technique's operation"; and "the theory or technique enjoys 'general acceptance' within a 'relevant scientific community.'" Kumho, Mem. Op. at 10 (quoting Daubert, 509 U.S. at 592-94).  The court also considered whether there were any "countervailing factors" operating in favor of admissibility that could outweigh those identified in Daubert, and, finding none, excluded Mr. Carlson's testimony.

The U.S. Court of Appeals for the Eleventh Circuit reversed, reviewing de novo the district court's decision.  131 F.3d 1433, 1435 (1997).  The court of appeals believed that Daubert was limited to "scientific" testimony and was inapplicable where an expert, such as Mr. Carlson, relied "on skill- or experience-based observations."  The Eleventh Circuit therefore held that "the district court erred as a matter of law by applying Daubert in this case."

The Supreme Court granted Kumho's petition for certiorari, which raised the question whether a trial court "may" consider Daubert's factors when determining the admissibility of an engineering expert's testimony.  A unanimous Court answered that question "yes."  In reaching that conclusion, the Court provided guidance to litigants seeking to introduce, or exclude, expert witnesses, regardless of the basis of their knowledge.

Trial Judges Are Gatekeepers For All Expert Testimony

Kumho makes clear that trial judges are to be "gatekeepers" for all expert testimony, regardless of the basis of the expert's knowledge.  In so holding, the Court rejected the position that Daubert is limited to "scientific" testimony, a proposition endorsed by the court of appeals below and several other appellate courts.  See, e.g., Compton v. Subaru of Am. Inc., 82 F.3d 1513 (10th Cir.), cert. denied, 519 U.S. 1042 (1996); Freeman v. Case Corp., 118 F.3d 1011 (4th Cir. 1997), cert. denied, 118 S. Ct. 739 (1998); McKendall v. Crown Control Corp., 122 F.3d 808 (9th Cir. 1997); Stagl v. Delta Air Lines Inc., 117 F.3d 76 (2d Cir. 1997).  According to the Court, Rule 702 makes "no relevant distinction between 'scientific' knowledge and 'technical' or 'other specialized' knowledge" (Kumho, Mem. Op. at 8), and thus, the basic "gatekeeping obligation" applies to all expert testimony.  The Court also found unmanageable an evidentiary rule that depends on a distinction between "scientific" and "nonscientific" knowledge, because "[t]here is no clear line that divides the one from the other."  Id.

In the post-Kumho world, expert witnesses will no longer be able to avoid Daubert scrutiny by convincing a court that their testimony is not "scientific."  Whether testimony is "scientific" or "nonscientific" is academic; the relevant issue is whether the expert testimony is reliable and relevant to an issue in the case.  To determine whether testimony is reliable requires an analysis of the data or facts on which the expert relied and the methodology the expert used to reach his or her conclusions.

Expert's Data and Methods Must Be Reliable

An expert witness's testimony may be called into question because of its "factual basis, data, principles, methods, or their application."  Kumho, Mem. Op. at 9.  Attorneys, therefore, should scrutinize the facts underlying an expert=s analysis.  A showing that the facts relied on by the expert are inaccurate, standing alone, could be enough to have the expert's testimony excluded.

An expert should be made to explain how he or she progressed from observation to conclusion, and how he or she knows that the conclusions are correct.  An expert who offers in response only his or her "experience" and "assurances" should be excluded, because such testimony amounts to nothing more than the "ipse dixit" of the expert.  General Electric Co. v. Joiner, 118 S. Ct. 512, 519 (1997); accord Kumho, Mem. Op. at 18; see id. at 15 (criticizing expert's reliance on "subjective[ness]" of analysis).

Daubert's Factors May Apply to All Expert Testimony

After an expert's methodology is precisely identified, it should be tested for reliability.  In Kumho, the Court noted that the Daubert factors "will often be appropriate" to do just that.  Kumho, Mem. Op., at 12.  Indeed, Justice Scalia, joined by Justices Clarence Thomas and Sandra Day O'Connor, stated that "in a particular case the failure to apply one or another of [the Daubert factors] may be unreasonable, and hence an abuse of discretion."  The questions identified in Daubert, therefore, provide a sensible beginning to an analysis of the reliability of any expert's testimony.

They are not the end of the process, however.  For example, "the presence of Daubert's general acceptance factor [does not] help show that an expert's testimony is reliable where the discipline itself lacks reliability, as, for example, do theories grounded in any so-called generally accepted principles of astrology or necromancy."  Id.  On the other hand, simply because an expert's testimony cannot clear one or more of the Daubert hurdles does not mean that it must be excluded.  Id.; see id. at 18.  But the expert should be prepared to explain why that shortcoming does not render the testimony unreliable.

There may be factors in addition to those identified in Daubert that bear on the reliability of a particular expert's testimony.  It is in this inquiry that the "flexibility" of the Daubert analysis comes into play.  See Kumho, Mem. Op. at 10; Daubert, 509 U.S. at 594.  Attorneys attempting to prove that an expert's testimony is reliable will want to demonstrate that the expert witness "employ[s] in the courtroom the same level of intellectual rigor that characterizes the practice of an expert in the relevant field."  Kumho, Mem. Op. at 12.  That showing could include evidence that the expert's methodology is similar to that used by professionals in the relevant field.  In a related vein, the fact that an expert is a professional witness who makes a living by testifying in courtrooms, rather than by developing products in laboratories or factories, generally weighs against the reliability of the expert's testimony.  See, e.g., Daubert v. Merrell Dow Pharmaceuticals Inc., 43 F.3d 1311, 1317 (9th Cir. 1995).

Same Standard of Reliability Applies to All Expert Witnesses

The rationale of Kumho compels the conclusion that the reliability standard for expert witnesses does not vary depending on the source of the expert's knowledge.  The Court noted that the language of Rule 702 makes "no relevant distinction" between the source of an expert's knowledge; "[t]he Rule, in respect to all such matters, establishes a standard of evidentiary reliability."  Kumho, Mem. Op. at 9.  A trial judge should therefore demand the same minimum threshold of reliability from a witness seeking to opine regarding expertise in an emerging field that the judge would require of an expert testifying with respect to a well-established subject matter.

Trial Judge's Analysis Is Reviewed For Abuse of Discretion

The Court emphasized that the manner in which a trial judge analyzes an expert's reliability, like the conclusion as to whether the testimony is reliable, is reviewed for abuse of discretion.  The practical consequence of this aspect of Kumho’s holding is that the battle regarding the admissibility of expert testimony will often be won or lost before the trial judge.

Appellate review will not be a toothless tiger, however.  As Justice Scalia explained, a trial court does not have the discretion "to abandon the gatekeeping function" or "to perform [it] inadequately."  And appellate courts have heeded that warning.  In Black v. Food lion Inc., 1999 U.S. App. LEXIS 5706 (March 30), for example, the Fifth Circuit reversed a lower court decision admitting expert testimony because it did not adequately identify and analyze the methodology relied on by the expert.  We should expect appellate courts to follow Black (and Kumho) in ensuring that trial courts rigorously test the particular methodologies used by expert witnesses.

Kumho requires that expert witness testimony be carefully analyzed, with particular focus on the expert's factual basis and methodology.  The Supreme Court has reaffirmed that all expert witnesses must be prepared to withstand the demanding scrutiny required by Rule 702.

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Kenneth S. Geller is a partner and Michael E.Lackey, Jr. is an associate in the Washington, D.C. office of Mayer, Brown & Platt, which represented Kumho Tire Co. before the Supreme Court.  Telephone:  (202) 263-3000. 
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[Copyright © 2000 Mayer, Brown & Platt. This Mayer, Brown & Platt article provides information and comments on legal issues and developments of interest to our clients and friends. The foregoing is not a comprehensive treatment of the subject matter covered and is not intended to provide legal advice. Readers should seek specific legal advice before taking any action with respect to the matters discussed herein.].