Opinion ID: 163939
Heading Depth: 2
Heading Rank: 3

Heading: The Standard for Admitting Expert Testimony

Text: 13 The admissibility of expert testimony is governed by Rule 702 of the Federal Rules of Evidence: 14 If scientific, technical, or other specialized knowledge will assist the trier of fact to understand the evidence or to 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, if (1) the testimony is based upon sufficient facts or data, (2) the testimony is the product of reliable principles and methods, and (3) the witness has applied the principles and methods reliably to the facts of the case. 15 Fed.R.Evid. 702 (2003). Rule 702 imposes on a district court a gatekeeper obligation to ensure that any and all scientific testimony or evidence admitted is not only relevant, but reliable. Daubert, 509 U.S. at 589, 113 S.Ct. 2786. Fulfilling the gatekeeper duty requires the judge to assess the reasoning and methodology underlying the expert's opinion and determine whether it is both scientifically valid and applicable to a particular set of facts. Id. at 592-93, 113 S.Ct. 2786. The Supreme Court has made clear that where [expert] testimony's factual basis, data, principles, methods, or their application are called sufficiently into question ... the trial judge must determine whether the testimony has `a reliable basis in the knowledge and experience of [the relevant] discipline.' Kumho Tire, 526 U.S. at 149, 119 S.Ct. 1167 (quoting Daubert, 509 U.S. at 592, 113 S.Ct. 2786). 16 To be reliable under Daubert, an expert's scientific testimony must be based on scientific knowledge, which implies a grounding in the methods and procedures of science based on actual knowledge, not mere subjective belief or unsupported speculation. 509 U.S. at 590, 113 S.Ct. 2786. In other words, an inference or assertion must be derived by the scientific method ... [and] must be supported by appropriate validation — i.e. `good grounds,' based on what is known. Id. While expert opinions must be based on facts which enable [the expert] to express a reasonably accurate conclusion as opposed to conjecture or speculation, ... absolute certainty is not required. Gomez v. Martin Marietta Corp., 50 F.3d 1511, 1519 (10th Cir.1995) (quotation omitted). The plaintiff need not prove that the expert is undisputably correct or that the expert's theory is `generally accepted' in the scientific community. Mitchell v. Gencorp Inc., 165 F.3d 778, 781 (10th Cir.1999). Instead, the plaintiff must show that the method employed by the expert in reaching the conclusion is scientifically sound and that the opinion is based on facts that satisfy Rule 702's reliability requirements. Id. 17 To assist in the assessment of reliability, the Supreme Court in Daubert listed four nonexclusive factors that the trial court may consider: (1) whether the opinion at issue is susceptible to testing and has been subjected to such testing; (2) whether the opinion has been subjected to peer review; (3) whether there is a known or potential rate of error associated with the methodology used and whether there are standards controlling the technique's operation; and (4) whether the theory has been accepted in the scientific community. 509 U.S. at 593-94, 113 S.Ct. 2786. As noted, the list is not exclusive, and district courts applying Daubert have broad discretion to consider a variety of other factors. Kumho Tire, 526 U.S at 150, 119 S.Ct. 1167 ([W]e can neither rule out, nor rule in, for all cases and for all time the applicability of the factors mentioned in Daubert .... Too much depends upon the particular circumstances of the particular case at issue.). 18 Generally, the district court should focus on an expert's methodology rather than the conclusions it generates. Daubert, 509 U.S. at 595, 113 S.Ct. 2786. However, an expert's conclusions are not immune from scrutiny: A court may conclude that there is simply too great an analytical gap between the data and the opinion proffered. Joiner, 522 U.S. at 146, 118 S.Ct. 512 ([N]othing in either Daubert or the Federal Rules of Evidence requires a district court to admit opinion evidence that is connected to existing data only by the ipse dixit of the expert.). In Joiner, when faced with a claim that the experts in question relied on studies that did not support their conclusions, the Supreme Court reviewed each study and concluded that the district court did not abuse its discretion in excluding the testimony. Id. at 145-46, 118 S.Ct. 512 ([I]t was within the District Court's discretion to conclude that the studies upon which the experts relied were not sufficient, whether individually or in combination, to support their conclusions....). 19 Under Daubert, any step that renders the analysis unreliable ... renders the expert's testimony inadmissible. This is true whether the step completely changes a reliable methodology or merely misapplies that methodology. Mitchell, 165 F.3d at 782 (quoting In re Paoli R.R. Yard PCB Litigation, 35 F.3d 717, 745 (3d Cir.1994)). It is critical that the district court determine whether the evidence is genuinely scientific, as distinct from being unscientific speculation offered by a genuine scientist. Id. at 783 (quoting Rosen v. Ciba-Geigy Corp., 78 F.3d 316, 318 (7th Cir.1996)). Regardless of the specific factors at issue, the purpose of the Daubert inquiry is always to make certain that an expert, whether basing testimony upon professional studies or personal experience, employs in the courtroom the same level of intellectual rigor that characterizes the practice of an expert in the relevant field. Kumho Tire, 526 U.S. at 152, 119 S.Ct. 1167. 20