Opinion ID: 1058169
Heading Depth: 2
Heading Rank: 1

Heading: Overview of the Admissibility of Expert Testimony

Text: Generally, questions pertaining to the qualifications, admissibility, relevancy, and competency of expert testimony are matters left to the trial court's discretion. McDaniel, 955 S.W.2d at 263. We may not overturn the trial court's ruling admitting or excluding expert testimony unless the trial court abused its discretion. Id. at 263-64. A trial court abuses its discretion if it applies an incorrect legal standard or reaches an illogical or unreasonable decision that causes an injustice to the complaining party. State v. Stevens, 78 S.W.3d 817, 832 (Tenn.2002). Tennessee Rules of Evidence 702 and 703 govern the admissibility of expert testimony in Tennessee. Rule 702 states that [i]f scientific, technical, or other specialized knowledge will substantially 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 in the form of an opinion or otherwise. Rule 703 provides: The facts or data in the particular case upon which an expert bases an opinion or inference may be those perceived by or made known to the expert at or before the hearing. If of a type reasonably relied upon by experts in the particular field in forming opinions or inferences upon the subject, the facts or data need not be admissible in evidence. The court shall disallow testimony in the form of an opinion or inference if the underlying facts or data indicate lack of trustworthiness. The trial court, therefore, must determine that the expert testimony is reliable in that the evidence will substantially assist the trier of fact to determine a fact in issue and that the underlying facts and data appear to be trustworthy. In addition to these specific rules, evidence generally must be relevant to be admissible. See Tenn. R. Evid. 401, 402. The issue in the present case concerns the reliability of the testimony of the plaintiffs' expert witnesses, Mr. Johannson and Dr. Harris. In McDaniel , we listed several nonexclusive factors that courts could consider in determining the reliability of scientific testimony, including (1) whether scientific evidence has been tested and the methodology with which it has been tested; (2) whether the evidence has been subjected to peer review or publication; (3) whether a potential rate of error is known; (4) whether . . . the evidence is generally accepted in the scientific community; and (5) whether the expert's research in the field has been conducted independent of litigation. 955 S.W.2d at 265; see also Daubert v. Merrell Dow Pharmaceuticals, Inc., 509 U.S. 579, 593-94, 113 S.Ct. 2786, 125 L.Ed.2d 469 (1993) (applying the first four factors in determining the reliability of scientific expert testimony pursuant to the Federal Rules of Evidence); Daubert v. Merrell Dow Pharmaceuticals, Inc., 43 F.3d 1311, 1317 (9th Cir.1995) (considering on remand the fifth factor in addition to the first four factors). The McDaniel factors also may be applied to nonscientific expert testimony. Stevens, 78 S.W.3d at 834; see also Kumho Tire Co. v. Carmichael, 526 U.S. 137, 152, 119 S.Ct. 1167, 143 L.Ed.2d 238 (1999) (holding that a trial court may consider the Daubert factors in assessing the reliability of nonscientific expert testimony in accordance with the Federal Rules of Evidence). In addition to the McDaniel factors, we have identified other nondefinitive factors that a trial court may consider in assessing the reliability of an expert's methodology. One such factor is the expert's qualifications for testifying on the subject at issue. Stevens, 78 S.W.3d at 835. This factor is applicable particularly where the expert's personal experience is essential to the methodology or analysis underlying his or her opinion. We, however, caution that using this factor as the sole basis of reliability would result in a reconsideration of the Rule 702 requirement that the expert witness be qualified by knowledge, skill, experience, training, or education to express an opinion within the limits of the expert's expertise. As a result, the expert testimony would become perilously close to being admissible based upon the ipse dixit of the expert. Robert J. Goodwin, The Hidden Significance of Kumho Tire Co. v. Carmichael: A Compass for Problems of Definition and Procedure Created by Daubert v. Merrell Dow Pharmaceuticals, Inc., 52 Baylor L.Rev. 603, 635 (2000); see Gen. Elec. Co. v. Joiner, 522 U.S. 136, 146, 118 S.Ct. 512, 139 L.Ed.2d 508 (1997) (cautioning against the admission of expert testimony that is connected to existing data only through the ipse dixit of the expert). Furthermore, the trial court should distinguish between `the marginally-qualified full-time expert witness who is testifying about a methodology that she has not employed in real life' and `the highly credentialed expert who has devoted her life's work to the actual exercise of the methodology upon which her testimony is based.' Sarah Brew, Where the Rubber Hits the Road: Steering the Trial Court Through a Post-Kumho Tire Evaluation of Expert Testimony, 27 Wm. Mitchell L.Rev. 467, 486 (2000). Another factor that we have identified is the connection between the expert's knowledge and the basis for the expert's opinion. Stevens, 78 S.W.3d at 835. The purpose of this factor is to ensure that an analytical gap does not exist between the data relied upon and the opinion offered. Id.; see Gen. Elec. Co., 522 U.S. at 146, 118 S.Ct. 512 (holding that experts, who opined that the plaintiff's exposure to certain chemicals and toxins in the workplace contributed to his cancer, relied upon studies that either were too dissimilar to the facts of the case or failed to link the cancer with the chemical exposure). This factor is important particularly when the expert's opinions are based upon experience or observations as these areas are not easily verifiable. Stevens, 78 S.W.3d at 834. A trial court, however, may conclude that an expert's opinions are reliable if the expert's conclusions are sufficiently straightforward and supported by a `rational explanation which reasonable [persons] could accept as more correct than not correct.' Id. (quoting Wood v. Stihl, 705 F.2d 1101, 1107-08 (9th Cir. 1983)). We continue to emphasize, however, that these factors are non-exclusive and that a trial court need not consider all of these factors in making a reliability determination. Rather, the trial court enjoys the same latitude in determining how to test the reliability of an expert as the trial court possesses in deciding whether the expert's relevant testimony is reliable. Kumho Tire Co., 526 U.S. at 152, 119 S.Ct. 1167. The objective of the trial court's gatekeeping function is to ensure 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. Id. Furthermore, upon admission, expert testimony will be subject to vigorous cross-examination and countervailing proof. Stevens, 78 S.W.3d at 835; McDaniel, 955 S.W.2d at 265. The weight of the theories and the resolution of legitimate but competing expert opinions are matters entrusted to the trier of fact. See McDaniel, 955 S.W.2d at 265. With these principles in mind, we turn to the trial court's rulings in the present case.