Opinion ID: 198219
Heading Depth: 2
Heading Rank: 1

Heading: Daubert Revisited.

Text: 9 The Evidence Rules generally confine the testimony of a lay witness to matters about which he or she has personal knowledge, see Fed.R.Evid. 602, although such a witness may offer opinions that are rationally based on [his or her] perception and helpful to a clear understanding of the witness' testimony or the determination of a fact in issue, Fed.R.Evid. 701. The Rules afford expert witnesses much more leeway. If scientific, technical, or other specialized knowledge will assist the trier of fact to understand the evidence or determine a fact in issue, a witness qualified as an expert by knowledge, skill, experience, training, or education, may testify thereto in the form of an opinion or otherwise. Fed.R.Evid. 702. Despite its apparent breadth, this language does not give experts carte blanche, but, rather, envisions some regulation of expert testimony by trial judges. The Court's opinion in Daubert furnishes the principal source of guidance on the proper fulfillment of this gatekeeping role. 10 We start with an historical perspective. Prior to Daubert, courts and commentators regarded Frye v. United States, 293 F. 1013 (D.C.Cir.1923), as the watershed case on the admission of expert opinion testimony. Under Frye, the admissibility of an expert opinion or technique turned on its general acceptance vel non within the scientific community. Id. at 1014. Daubert tackled the question of whether the Frye standard survived the passage of the Federal Rules of Evidence (and, in particular, Rule 702) and answered that question in the negative, holding that Rule 702 displaced the Frye test. See Daubert, 509 U.S. at 587-89, 113 S.Ct. 2786. 11 The Daubert Court's interpretation of Rule 702, drawn from its text, requires the trial judge to evaluate an expert's proposed testimony for both reliability and relevance prior to admitting it. See id. at 589-95, 113 S.Ct. 2786. The requisite review for reliability includes consideration of several factors: the verifiability of the expert's theory or technique, the error rate inherent therein, whether the theory or technique has been published and/or subjected to peer review, and its level of acceptance within the scientific community. See id. at 593-95, 113 S.Ct. 2786. The Court reasoned that due investigation of such matters will ensure that proposed expert testimony imparts scientific knowledge rather than guesswork. Id. at 592, 113 S.Ct. 2786. Withal, the factors that the Court enumerated do not function as a definitive checklist or test, but form the basis for a flexible inquiry into the overall reliability of a proffered expert's methodology. Id. at 593, 113 S.Ct. 2786. 12 Along with the reliability requirement, the Daubert Court imposed a special relevancy requirement. See id. at 591-92, 113 S.Ct. 2786. To be admissible, expert testimony must be relevant not only in the sense that all evidence must be relevant, see Fed.R.Evid. 402, but also in the incremental sense that the expert's proposed opinion, if admitted, likely would assist the trier of fact to understand or determine a fact in issue, see Daubert, 509 U.S. at 591-92, 113 S.Ct. 2786. In other words, Rule 702, as visualized through the Daubert prism, requires a valid scientific connection to the pertinent inquiry as a precondition to admissibility. Id. at 592, 113 S.Ct. 2786. 13 In General Elec. Co. v. Joiner, 522 U.S. 136, 118 S.Ct. 512, 139 L.Ed.2d 508 (1997), the Justices established the appropriate standard of appellate review for Daubert determinations, concluding that a reviewing tribunal should scrutinize a trial court's decision to allow or disallow the admission of expert testimony on Daubert grounds for abuse of discretion. See id. 118 S.Ct. at 517. Joiner also placed a gloss on Daubert 's insistence that trial courts focus on an expert's methodology, rather than his conclusions, in order to determine the reliability of his testimony. See Daubert, 509 U.S. at 595, 113 S.Ct. 2786. The Joiner Court moderated this position, acknowledging that 14 conclusions and methodology are not entirely distinct from one another. Trained experts commonly extrapolate from existing data. But nothing in either Daubert or the Federal Rules of Evidence requires a district court to admit opinion evidence which is connected to existing data only by the ipse dixit of the expert. A court may conclude that there is simply too great an analytical gap between the data and the opinion proffered. 15 Joiner, 118 S.Ct. at 519. Thus, while methodology remains the central focus of a Daubert inquiry, this focus need not completely pretermit judicial consideration of an expert's conclusions. Rather, trial judges may evaluate the data offered to support an expert's bottom-line opinions to determine if that data provides adequate support to mark the expert's testimony as reliable. 2 16 Daubert and Joiner, though critically important, do not represent the sum total of available jurisprudential insights. Since Daubert hove into view, the courts of appeals have made significant contributions to an understanding of how to separate reliable from unreliable science and how to apply the intuitive idea of fit--as courts have come to call the special kind of relevance that Daubert demands--to live litigation scenarios. See, e.g., Baker v. Dalkon Shield Claimants Trust, 156 F.3d 248, 252-54 (1st Cir.1998); Daubert v. Merrell Dow Pharm., Inc., 43 F.3d 1311, 1316-22 (9th Cir.1995). Nonetheless, choreographing the Daubert pavane remains an exceedingly difficult task. Few federal judges are scientists, and none are trained in even a fraction of the many scientific fields in which experts may seek to testify. Moreover, even though Daubert and its progeny require trial judges to evaluate the level of support provided by complex scientific studies and experiments in myriad disciplines, reliability and relevance remain legal judgments. Trial judges cannot abdicate the responsibility for making those judgments by delegating them to the scientific community. 17 To complicate matters further, Daubert issues rarely arise in a vacuum, but, rather, frequently collide in practice with the requirements of other rules of evidence, especially Fed. R. Evid. 403. 3 This phenomenon adds yet another dimension to the decisional calculus. See, e.g., Baker, 156 F.3d at 254. 18