Daubert UpdateIn this issue: Daubert v. Merrell Dow Pharm., Inc., 509 U.S. 579 (1993), and its progeny provide product liability defendants with a powerful tool to battle "junk science" and groundless litigation. Over the last 18 months, a number of decisions have been handed down which give clarity to the scope of the district courts' authority to exclude expert opinion testimony. One of the most vexing questions raised, but not answered by the Daubert court, was: What components of an expert's testimony are the district court to assess? Daubert states: "The focus [of the inquiry], of course, must be solely on principles and methodology, not on the conclusions that they generate." Plaintiffs seized on this language and argued that district courts could assess only "methodology," and thus, so long as an expert was following sound methodology, the expert's conclusions must be admissible. Plaintiffs' argument would reduce Daubert to a nullity since an expert can easily assert that at some level she or he is using a reliable methodology. Recently, different courts found ways of dealing with this troublesome language from Daubert in order to reach the right result . exclusion of unreliable expert testimony. In Lust v. Merrell Dow Pharm., Inc., 89 F.3d 594 (9th Cir. 1996), the Ninth Circuit attempted to remain true to the Supreme Court's bifurcation of methodology and conclusions by noting that "when a scientist claims to rely on a method practiced by most scientists, yet presents conclusions that are shared by no other scientist, the district court should be wary that the method has not been faithfully applied." The Ninth Circuit held that to enforce the principle of the expert's burden of proving admissibility, "the district court can exclude the opinion if the expert fails to identify and defend the reasons that his conclusions are anomalous." A few months later in Hall v. Baxter Healthcare Corp., 947 F. Supp. 1387 (D. Or. 1996), (Brobeck representing Baxter) Judge Robert E. Jones essentially abandoned the methodology/conclusion dichotomy by noting "there appears to be no clear demarcation between scientific methodology and the conclusions it generates." Instead, Judge Jones held, a court should not ignore any step in the scientific process, "but must ensure that in each step, from initial premise to ultimate conclusion, the expert faithfully followed valid scientific methodology." Most recently, the Supreme Court vindicated Judge Jones' approach. General Electric Co. v. Joiner, 118 S. Ct. 512 (1997) rejected plaintiffs' methodology arguments (and implicitly rejected the supporting sentence from Daubert) by stating that "conclusions and methodology are not entirely distinct from one another." The Joiner court ruled that a trial court may conclude that there is simply too great an analytical gap between the data and the opinion proffered and thus exclude the expert. The Joiner court also settled the question of how expert admissibility determinations would be reviewed in the appellate courts. The often dispositive consequences of expert exclusions had motivated at least two federal circuits to adopt a standard of review for those determinations that arguably was more stringent than the abuse of discretion standard traditionally applied to admissibility decisions. The Court resolved this circuit split summarily by stating that the question of admissibility of expert testimony is reviewable under the abuse of discretion standard and that trial courts should receive deference in their admissibility decisions. Significantly, the Court went on, in somewhat uncharacteristic fashion, to analyze in detail the expert testimony excluded by the trial court and to determine that the district court had not abused its discretion in excluding that testimony because "the studies upon which the experts relied were not sufficient, whether individually or in combination, to support their conclusions that [the plaintiff's] exposure to PCPs contributed to his cancer." The Joiner opinion makes it clear that district court judges are expected to scrutinize carefully, and in detail, the scientific basis of proffered expert testimony. Interestingly, Justice Breyer's concurring opinion in Joiner vindicated another part of the Hall case: the appointment of neutral experts to aid a court in its gatekeeping duties. In Hall, Judge Jones appointed four experts to act as science advisors to help him interpret a voluminous record, which included lengthy testimony by experts on both sides and volumes of scientific articles. All four experts issued reports to the court in their respective fields of immunology, rheumatology, chemistry, and epidemiology, which Judge Jones eventually appended to his published decision. In Joiner, Justice Breyer recommended this kind of "cooperative effort, from the scientific to the legal community." With this signal of approval from the Supreme Court, district courts may increase their use of court-appointed experts to fulfill Daubert judicial responsibilities. Joiner has left some questions unresolved. One of the most troublesome issues is whether the Daubert analysis applies to opinions that are not based on any particular technique or theory, but simply upon an expert's training and experience. A few district courts and appellate courts have held that Daubert does not apply in that circumstance. See, e.g., Compton v. Subaru of Am., 82 F.3d 1513 (10th Cir. 1996), cert. denied, Subaru of Am. v. Compton, 117 S. Ct. 611 (1996). Such reasoning, however, also leads to reductive consequences that defy the intent of Daubert. It makes little sense to scrutinize testimony that relies on scientific procedures or data, but to preclude such scrutiny where the testimony is based on nothing but the experts' say-so. A related and still unresolved question is to what extent medical doctors may testify regarding disease causation based on their training and experience using the methodology of differential diagnosis. Plaintiffs' medical experts in some cases have attempted to testify that differential diagnosis could be used to draw a causal connection between a product or substance and a particular plaintiff's disease (specific causation), even though there is no reliable evidence that the product or substance could in general cause that disease (general causation). Judge Jones in Hall correctly observed that differential diagnosis goes only to a specific causation opinion and thus such testimony is irrelevant and inadmissible, unless and until there is proof of general causation. Most courts that have considered the question have ruled similarly, but a Fifth Circuit panel recently opined that differential diagnosis based on training and experience is a reliable methodology for assigning causation generally and that the district court had erred in excluding such testimony. See Moore v. Ashland Chem., Inc., 1997 U.S. App. LEXIS 33501 (5th Cir. Tex. Nov. 24, 1997), reh'g, en banc, granted, Moore v. Ashland Chem., 1997 U.S. App. LEXIS 32349 (5th Cir. Tex. Nov. 12, 1997). Rehearing en banc has been granted, however, and this aberrant and illogical decision should be overturned. More in this issue: |
Products Liability Update: Spring 1998: Daubert Update
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