Indiana Law Review Closing the Doors on Unsupported Speculation: Joiner's Effect on the Admissibility OF Expert Testimony Theresa M. Moore* Introduction The critical debate over what types of scientific testimony and evidence should survive the scrutiny of the Federal Rules of Evidence continues to progress. Attorneys continuously search for guidance regarding the admission of expert testimony because admissibility decisions can be a pivotal point in determining the viability and/or outcome of a particular claim.' Due to the Supreme Court's goal to exclude "junk science,"^ the Court has emphasized the importance ofscientifically accurate (or reliable) expert evidence and testimony. In achieving this goal, however, the scope ofa district court judge's authority to exclude a particular expert's testimony has never been clearly defined. In the meantime, courts continue to experience an influx of new scientific and non- scientific testimony. Therefore, it is critical that district court judges are given guidance to assist them in their determinations of admissibility. Over five years ago, the Supreme Court created a new standard governing the admissibility of expert testimony in Daubert v. Merrell Dow Pharmaceuticals, Inc? After defining the requirements for the admissibility of expert testimony, the Court set forth a directive addressing the scope of district court judicial authority. The Supreme Court specifically provided that the district courtjudge, when acting as the gatekeeper, must focus "solely on [the] principles and methodology [of the experts and], not on the conclusions they generate.'"* As a result of Daubert' s distinction between methods and conclusions, conflicting views developed as to the scope ofa district court's power when determining the * J.D. Candidate, December 1999, Indiana University School ofLaw—Indianapolis; B.S., 1993, Ball State University. 1 . See Patrick C. Barry, Admissibility ofScientific Evidence in the Remand o/Daubert v. Merrell Dow Pharmaceuticals, Inc.. Questioning the Answers, 2 WiDENER L. Symp. J. 299, 305 (1997) (noting that evidence of causation now must be presented via expert testimony, and therefore, many suits can be precluded if the expert's opinion is speculatively based on existing data); Michael H. Gottesman, From Barefoot to Daubert to Joiner; Triple Play or Double Error?, 40 ARIZ. L. Rev. 753, 769 (1998). 2. 5ee Graham v.Playtex Prods., Inc., 993 F.Supp. 127, 134(N.D.N.Y. 1998) (stating that Dauberfs primary concern was the exclusion of "junk science"); Charles F. Preuss, Closing the Door onJunk Science, 65 Def.Couns. J. 323, 323 (1998) (illustrating how the appropriate standard of admissibility is important to ensure that courtrooms are not infiltrated with "junk science"); Richard B. Racine et al., The Battle over Science in the Courtroom, FED. LAW., Feb. 1995, at 36, 40; Jeffrey Robert White, Experts and Judges, TRIAL, Sept. 1998, at 91, 91. 3. 509 U.S. 579(1993). 4. Mat 595. 350 INDIANA LAW REVIEW [Vol. 33:349 admissibility of an expert's testimony.^ Some of the circuit courts gave great deference to the Supreme Court's direct limitation that ajudge's focus should be on the reliability of an expert's methods and not on the expert's conclusions.^ Other circuit courts gave less deference to the Supreme Court's distinction and allowed a "district [court] judge to evaluate both the scientific validity of the expert's methodology and the strength of the expert's conclusions."^ After many years of confusion, the Supreme Court revisited Daubert in General Electric Co. v. Joiner} Although the Court's primary concern in Joiner was identifying the appropriate standard of review governing a district court's decision to admit or exclude expert testimony, the Court also provided insight into Dauberfs "methodology/conclusion" distinction.^ While it is unclear whether Jo/w^r conclusively extended the trial court judge's gatekeeping role to include an expert's conclusions,'^ the Supreme Court's opinion has resoundingly 5. See J. KennardNeal, Life After JoinQr, How Will the NewSupreme Court Decision Affect the Admissibility of Expert Testimony in Georgia?, 3 Ga. B. J. 32, 34 (1998) (discussing the growing debate as to the scope of "the district court's gatekeeper role in evaluating the 'conclusions' of the proposed expert"); Anthony Z. Roisman, The Courts, Daubert and Environmental Torts: Gatekeepers or Auditors?, 14 PACE Envtl. L. Rev. 545, 562 (1997) (stating that Daubert's seemingly bright-line distinction between methodology and conclusions has not produced uniform results among the circuit courts); Ruth Saunders, The Circuit Courts 'Application o/ Daubert v. Merrell Dow Pharmaceuticals, Inc., 46 Drake L. Rev. 407, 422-23 (1997) (illustrating that posi-Daubert circuit court opinions have led to two distinct interpretations ofthe Supreme Court's opinion). 6. See infra notes 52-53 and accompanying text; see also Kenneth J. Chesebro, Taking Daubert '5^ "Focus" Seriously: The Methodology/Conclusion Distinction, 15 CardozoL. Rev. 1745, 1746 (1994) (indicating that the persuasiveness of the expert's opinion is beyond the scope ofan admissibility determination under Rule 702); Lawrence S. Pinsky, The Use ofScientific Peer Review and Colloquia to Assist Judges in the Admissibility ofGatekeeping Mandated by Daubert, 34 Hous. L. Rev. 527, 542 (1997) (stating that a judge's focus is limited to the validity of the expert's underlying methodology and not whether the expert's testimony or ultimate conclusion is correct); Saunders, supra note 5, at 422 (stating that circuit courts, supporting Daubert's bright-line distinction, distinguished between the trial judge's initial role ofdetermining whether to admit the proffered scientific testimony and the jury 's role ofdeciding the "weight" ofthe expert's opinion). 7. Saunders, supra note 5, at 422 (intimating that the Ninth Circuit interpreted Daubert' s gatekeeping role broadly); see infra notes 72-101 and accompanying text. 8. 522 U.S. 136(1997). 9. The Supreme Court granted certiorari "to determine what standard an appellate court should apply in reviewing a trial court's decision to admit or exclude expert testimony under Daubertr Id. at 138. 1 0. Some commentators believe that the combined effect ofthe Daubert and Joiner opinions allows a district court judge to exclude expert testimony if the judge is in disagreement with the expert's application of a reliable methodology in arriving at the proffered conclusion. See. e.g., Gottesman, supra note 1, at 772; Preuss, supra note 2, at 323. However, there are others who maintain that the Joiner decision should not be construed so broadly and that the Supreme Court's opinion did not extend the judge's gatekeeping role to include an expert's conclusions. See, e.g.. 1 999] ADMISSIBILITY OF EXPERT TESTIMONY 3 5 1 impacted the admissibility of expert testimony. This Note analyzes and summarizes the various standards governing the admissibility of expert testimony and provides a glimpse at Joiner'^ effect on future decisions. Part I provides a historical background ofexpert testimony and describes the differing opinions on a district court judge's authority to analyze the validity or reliability of an expert's conclusion(s). Part II addresses the history of Joiner from the district court decision to the appeal to the Supreme Court. Part III suggests that the Supreme Court's decision in Joiner and the proposed amendments to Federal Rule of Evidence 702 represent a retreat from Dauberfs methodology/conclusion distinction. Finally, part IV discusses how the Court's decision signals a return to a more restrictive era governing expert testimony admissibility determinations under Federal Rule of Evidence 702. I. History of Expert Testimony A. The Step Awayfrom Requiring General Acceptance For more than seventy years, the admissibility of expert testimony was governed by the "general acceptance" test set forth in Frye v. United States}^ Under Frye, a trial judge was required to exclude evidence based on scientific principles that had not gained general acceptance in that field. '^ The proponent of scientific evidence was required to demonstrate that (1) "the expert's conclusions represent[ed] an established view within the field" and that (2) "the expert's conclusions . . . [were] sufficiently accurate to be reliable."'^ Frye's "general acceptance" test was first called into question when the Federal Rules of Evidence ("FRE") were adopted in 1975.'"^ Specifically, the Frye test conflicted with FRE 702, which provides "[i]f 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."'^ Because Rule 702 did not require "that the offered evidence be generally accepted within the scientific community," this established a conflicting view as to the admissibility ofexpert testimony.'^ This discrepancy developed into a split among the circuit courts as to whether the Frye standard survived under the Federal Rules. In 1993, the Supreme Court Chesebro, supra note 6, at 1 746; Pinsky, supra note 6, at 542. 11. 293 F. 1013, 1014(D.C. Cir. 1923). 12. See id. at \0\4. 13. Peter B. Oh, Assessing Admissibility ofNonscientific Expert Evidence Under Federal Evidence Rule 702, 64 Def. Couns. J. 556, 564 (1997). 14. ^eeRussellD. Marlin,Note, 21 U. Ark. Little RocK L. Rev. 133, 139(1998). 15. Fed. R. EviD. 702. 1 6. See Racine et al., supra note 2, at 38; see also Marlin, supra note 1 4, at 1 39 (indicating that ''''Frye''?, replacement was not fully recognized until the court incorporated it into the Daubert standard in 1993."). 352 INDIANA LAW REVIEW [Vol. 33:349 granted certiorari in Daubert v. Merrell Dow Pharmaceuticals, Inc}^ to (1) resolve the conflict between Frye's restrictive approach and the more liberal approach promulgated in PRE 702 and (2) determine the proper standard for admitting scientific, expert testimony. ^^ B. The Daubert Decision The primary issue in Daubert was whether the plaintiffs' expert could testify as to epidemiological studies establishing the "causational" link between the plaintiffs' birth defects and their pregnant mothers' use of the antinausea drug Bendectin. The defendant moved for summary judgment and offered a supporting affidavit of an expert stating that after his review of all Bendectin literature, he was unable to find a study indicating that use of the drug caused fetus malformations.^^ In opposition, the plaintiffs offered the testimony ofeight experts claiming that the use of Bendectin could cause birth defects.^^ The plaintiffs' experts based their opinion on the use of animal studies and a "reanalysis of previously published epidemiological (human statistical) studies."^' The district court applied F/^^e's general acceptance test and excluded the plaintiffs' expert testimony. As a result, the plaintiffs were unable to sustain their burden ofcausation and the district court granted the defendant's motion for summary judgment.^^ The Ninth Circuit Court of Appeals also applied Frye's general acceptance test and affirmed the district court's decision to exclude the expert testimony.^^ The Supreme Court vacated the decision by the Ninth Circuit and unanimously concluded that Frye's general acceptance test "was superseded by the adoption of the Federal Rules of Evidence."^'* The Supreme Court also determined that federal judges, as "gatekeepers,"^^ are to apply a two-step analysis under PRE Rules 104(a)^^ and 702 to determine any preliminary 17. 506 U.S. 914 (1992 (mem.) 18. See Daubert v. Merrell Dow Pharm., Inc., 509 U.S. 579, 585 (1993). 19. See id. at 5S2. 20. See id. at 583. 21. M (citations omitted). 22. See id. at 583-84. 23. See Daubert v. Merrell Dow Pharm., Inc., 951 F.2d 1 128 (9th Cir. 1991). 24. Daubert, 509 U.S. at 587, 589. Specifically, Rule 702 governs the admissibility of expert testimony. See id. at 588. 25. Id. at 596. See Racine et al., supra note 2, at 39 (stating that a trial judge must act as a gatekeeper to "assess whether the reasoning or methodology underlying the testimony is scientifically valid and can be applied properly to the facts at issue"). 26. PRE 104(a) states: Preliminary questions concerning the qualification of a person to be a witness, the existence of a privilege, or the admissibility of evidence, shall be determined by the court, subject to the provisions of subdivision (b) [discussing relevancy admissions conditioned of fact]. In making its determination it is not bound by the rules of 1999] ADMISSIBILITY OF EXPERT TESTIMONY 353 questions regarding the reliability and relevance ofan expert's testimony.^^ The two-step analysis requires the trial judge to conduct an initial determination as to whether "the expert is proposing to testify to (I) scientific knowledge that (2) will assist the trier of fact to understand or determine a fact in issue."^^ Therefore, the combination ofboth prongs requires the judge to assess "whether the reasoning or methodology underlying the testimony is scientifically valid and . . . whether that reasoning or methodology properly can be applied to the facts m issue. Dauberfs first prong ensures scientific reliability by requiring that the proffered testimony be based on scientific knowledge.^^ Basically, this reliability prong requires that the testimony be supported by valid, scientific methods and procedures.^' The testimony's reliability is determined by applying Dauberfs non-exclusive list of factors which include: (1) whether the expert's theory or technique "can be (and has been) tested[,]"^^ (2) "whether the theory or technique has been subjected to peer review and publication[,]"^^ (3) "the known or potential rate of error,"^"* and (4) whether the technique is generally accepted in the scientific community.^^ Dauberfs second prong, in contrast, confirms the relevance or "fitness" ofthe proffered testimony by requiring "that the evidence or testimony assist the trier of fact to understand the evidence or to determine a fact in issue."^^ Therefore, the goal is to keep unreliable or irrelevant evidence evidence except those with respect to privileges. Fed.R.Evid. 104(a). 27. See Daubert, 509 U.S. at 589; see also FEDERAL JUDICIAL CENTER, REFERENCE MANUAL ON Scientific Evidence 45-46 (1994) [hereinafter Reference Manual]. 28. Daubert, 509 U.S. at 592. 29. Id. at 592-93; see also Jonathan R. Schofield, Note, A Misapplication o/ Daubert.- Compton V. Subaru of America Opens the Gatefor Unreliable and Irrelevant Expert Testimony, 1997 BYU L. REV. at 489, 493. 30. See Daubert, 509 U.S. at 590. Scientific knov^ledge requires that the testimony is grounded "in the methods and procedures of science" and "connotes more than subjective belief or unsupported speculation." Id. Under this standard, scientific knowledge is described as "an inference or assertion [that is] derived by the scientific method" and is "supported by appropriate validation—i.e., 'good grounds,' based on what is known." Id. See also Shelly Storer, Note, The Weight Versus Admissibility Dilemma: Daubert 's Applicability to a Method or Procedure in a Particular Case, 1998 U. ILL. L. Rev. 231, 235. 31. See Kurtis B. Reeg & Cawood K. Bebout, What 's It AllAbout, Daubert.?, 55 J. Mo. Bar 369, 369 (1997) (indicating that "a valid scientific connection to the pertinent inquiry" is a precondition to Rule 702 admissibility) (quoting Daubert, 509 U.S. at 592); Saunders, supra note 5, at 410 (stating that Daubert' s first prong "focuses on the determination ofwhether the reasoning or methodology applied by the expert is scientifically valid"). 32. Daubert, 509 U.S. at 593. 33. Id. 34. Id. at 594. 35. See id. 36. Id. at 591 (citations omitted). 354 INDIANA LAW REVIEW [Vol. 33:349 from the jury's purview.^^ In applying both Daubert prongs, the Court emphasized that under PRE 702, a district courtjudge's inquiry should be flexible and that thejudge should focus on the expert's underlying methodology and not the conclusion generated.^^ The Court also noted that any concerns of admitting ill-founded conclusions are safeguarded by vigorous cross-examination, presentation of contrary evidence, and careful instructions on burden of proof.^^ According to the Court, the Federal Rules of Civil Procedure ("FRCP") also provide further protections against the admission of ill-founded conclusions.'^^ Irrespective of whether an expert's testimony satisfies the requirements ofFRE 702, the district courtjudge may conclude that the evidence is insufficient to maintain the plaintiffs burden to persuade a "reasonablejuror to conclude that the position more likely than not is true.'"^' In such an event, the judge remains free to direct a judgment under FRCP 50(a) or to grant summary judgment under FRCP 56.^^ The Court viewed the use of these procedural devices as a sufficient safeguard and a more appropriate resolution than the wholesale exclusion of expert testimony under Frye's general acceptance test/^ The Court recognized that its flexible approach may still "prevent the jury from learning of authentic insights and innovations.'"*"* However, the Court noted that the balance should always be struck in favor of admitting the proffered testimony.'*^ In the wake of Daubert, many articles were written assessing the Supreme Court's effect on the admissibility ofexpert testimony. The articles discussed the challenging responsibilities imposed upon district court judges to act as a gatekeepers and to assess the validity of scientific expert testimony. Many believed that the Daubert decision required district court judges to become "amateur scientists" in order to make admissibility determinations on complex scientific evidence and testimony.''^ One commentator even opined that 37. See REFERENCE MANUAL, supra note 27, at 46. 38. See Daubert, 509 U.S. at 594-95. 39. See id. at 596. 40. See id. [I]n the event the trial court concludes that the scintilla ofevidence presented supporting a position is insufficient to allow a reasonable juror to conclude that the position more likely than not is true, the court remains free to direct ajudgment, Fed. Rule Civ. Proc. 50(a), and likevy^ise to grant a summary judgment. Fed. Rule Civ. Proc. 56. Id 41. Id. 42. See id. 43. See id.; see also Saunders, supra note 5, at 413-14 (discussing concerns over abandoning Frye's more stringent approach for Daubert's flexible approach). 44. Daubert, 509 U.S. at 596-97. 45. See id.; Saunders, supra note 5, at 4 14. 46. See, e.g., John M. Conley & David W. Peterson, The Science of Gatekeeping: The FederalJudicial Center's New Reference Manual on Scientific Evidence, 74 N.C. L. REV. 1 183, 1 1 86 ( 1 996) (discussing the urgent need for the publication ofthe Federal Judicial Center's science 1999] ADMISSIBILITY OF EXPERT TESTIMONY 355 Dauberfs gatekeeping requirement sparked more questions than it answered/^ C. Confusion After Daubert Even though the Daubert ruling clarified several issues regarding the admissibility ofexpert testimony, the Court's decision prompted the development ofnew uncertainties. One ofthe burgeoning issues was whether a district court could exclude expert testimony that was based upon reliable methodology merely because the court did not agree with the reliability of the expert's conclusion/^ The circuit courts responded differently to this issue, and as a result, a circuit court split developed/^ The courts' disparate rulings resulted from attempts to balance Dauberfs two-prong requirements of reliability and relevance (i.e., "fitness") against Dauberfs methodology/conclusion distinction limiting the district courtjudge's scope ofadmissibility determinations.^^ The circuit courts' attempts to balance these competing requirements resulted in two different approaches for determining at what point a district courtjudge's gatekeeping role ends and the jury's role (as factfinder) begins. 1. Weight'Ofthe-Evidence Approach.—The first approach, the "weight-of- the-evidence approach," applies a strict interpretation of Daubert that distinguishes "between the initial role of the trial judge in determining the admissibility of scientific expert testimony and the weight the jury is to give that testimony—^the methodology/conclusion distinction."^' Circuit courts employing this approach believed that if a proponent established the expert's reliance on a standard scientific methodology, the trial judge had no inherent or implicit authority to exclude the expert's testimony, no matter how absurd the conclusion.^^ These courts allowed the jury (not the judge) to analyze the manual to assist judges). 47. See Racine et al., supra note 2, at 38. 48. See Conley & Peterson, supra note 46, at 1 198; see also Pinsky, supra note 6, at 542 (indicating confusion as to whether an expert's conclusions were beyond the purview of the trial judge's determination ofadmissibility). The Supreme Court in Daubert failed to clarify the extent of a district court judge's authority to review the expert's application of a scientific technique or methodology. See Storer, supra note 30, at 236. 49. See Roisman, supra note 5, at 562 (stating that Daubert's bright-line distinction did not yield uniform results among the circuit courts); Saunders, supra note 5, at 423 (opining that the circuit courts have adopted two distinct readings as to the scope of a district court judge's gatekeeping role under Daubert). 50. See Storer, supra note 30, at 246. 5 1 . Saunders, supra note 5, at 422. 52. S'ee United States V. Bonds, 12F.3d540,556(6thCir. 1993) (holding that "the Daw^er/ Court has instructed the courts that they are not to be concerned with the reliability of the conclusions generated by valid methods, principles and reasoning. Rather, they are only to determine whether the principles and methodology underlying the testimony itself are valid."); Christopherson v. Allied-Signal Corp., 939 F.2d 1 1 06, 1 1 1 1 (5th Cir. 1 99 1 ) (en banc), cert, denied, 503 U.S. 912 (1992) (stating that the focus should be on the expert's methodology and not the 356 INDIANA LAW REVIEW [Vol. 33:349 expert's application ofa "reliable" methodology to the facts at hand.^^ Under the weight-of-the-evidence approach, the judge's role is to determine whether or not an expert's opinion is based on more than mere conjecture; the jury's role is to determine whether an expert's testimony is credible.^"* Circuit courts exercising this approach give credence to the adversarial system's use ofcross-examination, presentation of evidence, well-crafted jury instructions,^^ and Dauberf^ differentiation between methodology and conclusions. Dauberfs bright-line distinction was viewed as a necessary dividing line and limitation upon the judge's authority.^^ Without Dauberfs delineation between methods and conclusions, a district court judge could consider the expert's ultimate conclusion in making her determination ofadmissibility and, as a result, thejudge would inappropriately encroach upon thejury's role.^^ Therefore, some commentators argue that a more expansive approach ofdetermining admissibility inappropriately extends a district court judge's role as gatekeeper because nothing in the Supreme Court's opinion in Daubert requires or mandates that the judge determine whether the expert's conclusions are right or wrong.^^ Circuit courts applying the weight-of-the-evidence approach, such as the District of Columbia, illustrate the concerns surrounding a more expansive gatekeeping role and the importance of Dauberfs methodology/conclusion conclusions); Peteet v. Dow Chem. Co., 868 F.2d 1428, 1433 (5th Cir. 1989) (providing that as long as an expert's methodology is well-founded, the nature ofthe expert's conclusion is irrelevant to admissibility, even if it is controversial or unique). "[A]n opinion must be admitted once an expert demonstrates reliance on a standard scientific methodology; otherwise, the court would be second-guessing the expert's conclusion contrary to Daubert.'' REFERENCE Manual, supra note 27, at 77. See also Conley & Peterson, supra note 46, at 1 1 95 (indicating that Daubert implies that even if an expert's conclusions are absurd, the judge has no authority to exclude the testimony if the expert uses a reliable scientific method); Pinsky, supra note 6, at 542 (stating that a judge's focus is limited to the validity ofthe expert's underlying methodology and not whether the expert's testimony or ultimate conclusion is correct). 53. 5ee United States v.Chischilly, 30 F.3d 1144, 11 52-54 (9th Cir. 1994) (holding that the DNA expert's application ofDNA profiling procedures was a question ofweight to be determined by the jury), cert, denied, 513 U.S. 1 132 (1995). Once Rule 702 has been met in regard to the scientific method in the abstract, the scientific testimony will go to the finder of fact, unless the judge determines that other Federal Rules of Evidence preclude the jury from considering the testimony. See Storer, supra note 30, at 240. 54. See Roisman, supra note 5, at 550. 55. See Storer, supra note 30, at 238. 56. See Chesebro, supra note 6, at 1 753 (stating that the Daubert decision was made in vain unless a district court judge's focus remains on the expert's procedures and methodologies). 57. See Saunders, supra note 5, at 4 1 8. 58. The Supreme Court did not "articulate any legal rationale for why the conclusion reached by an expert bears on the Rule 702 admissibility inquiry, as long as the expert is using a proper methodology." Chesebro, supra note 6, at 1 750. In fact, the Daubert opinion "demonstrates that even the most fervent disagreements with an expert's conclusion are irrelevant under Rule 702." Id. at 1751. See Conley & Peterson, supra note 46, at 1 198-99. 1999] ADMISSIBILITY OF EXPERT TESTIMONY 357 distinction. In Ambrosini v. Labarraque,^^ a pregnant mother's use ofthe drugs Bendectin and Depo-Provera was alleged to cause birth defects. The defendants, the mother's physician and the drug manufacturer, moved for summaryjudgment, alleging that the plaintiffs were unable to prove that the birth defects were caused by the mother's use of the drug.^^ The district court agreed and granted the motion.^' The district court's decision was reversed on appeal^^ because the district court failed "to distinguish between the threshold question of admissibility and the persuasive weight to be assigned the expert evidence. . . ."^^ The appeals court noted that Dauberfs relevance prong requires an expert's proffered testimony to exceed subjective beliefor unsupported speculation,^"* However, the court stated that: [TJhere is nothing in Daubert to suggest that judges become scientific experts, much less evaluators of the persuasiveness of an expert's conclusion. Rather, once an expert has explained his or her methodology, and has withstood cross-examination or evidence suggesting that the methodology is not derived from the scientific method, the expert's testimony, so long as it "fits" an issue in the case, is admissible under Rule 702 for the trier of fact to weigh.^^ Consequently, the appeals court disagreed with the district court's decision excluding plaintiffs' expert testimony. The appeals court reasoned that Daubert did not require the exclusion ofthe expert's underlying evidence nor the expert's ultimate conclusion merely because the judge disagreed with studies indicating the lack of a causal link between the drug and the resulting birth defects.^^ The appeals court further found that the expert's inability to reference an existing epidemiological study supporting his conclusion was not fatal to the issue of admissibility. In fact, the appeals court admitted the expert testimony because the expert was able to explain that he considered all ofthe available data and utilized traditionally accepted methods to reach his conclusion that Depo- Provera could cause the plaintiffs type of birth defects.^^ In support of this 59. 101 F.3d 129 (D.C. Cir. 1996). 60. 5ee/£/. at 131. 6 1 . See id. 62. Seeid.dXXAX. 63. Id. at 131. With respect to Daubert's reliability prong, the court noted Daubert' s instruction that a district court's focus should be limited to the methodology and principles of the plaintiffs expert and not on the ultimate conclusions rendered. See id. at 133. 64. See id. "Under the first prong of the analysis, the district court's focus is on the methodology or reasoning employed. Scientific implies a grounding in the methods and procedures of science and knowledge connotes more than subjective belief or unsupported speculation." Id. (internal quotes omitted) (quoting Daubert, 509 U.S. at 590). 65. /^. at 134. 66. See id. at \36. 67. See id. at 131. 358 INDIANA LAW REVIEW [Vol. 33:349 decision, the appeals court stated that "when experts are 'concededly well qualified in their fields,' the fact that a case may be the first of its type, or that the plaintiffs doctors may have been the first alert enough to recognize a causal connection, should not preclude admissibility of the experts' testimony. "^^ Thus, in balancing Daubert's requirements of reliability and relevance (i.e., "fitness") against Z)awZ?er/'s methodology/conclusion distinction, the Ambrosini court favored the latter ofthe two requirements in order to support the admission of novel scientific evidence. As a result of the circuit court's reasoning and approach to Dauberfs requirements for admitting expert testimony, the Ambrosini decision became one of the primary examples of maintaining Dauberfs bright-line distinction under the weight-of-the-evidence approach. 2. Admissibility Approach.—^The second approach is termed the "admissibility approach."^^ This approach places more emphasis on Dauberfs "fitness" requirement and interprets Daubert as giving trial judges a more active gatekeeping role that "enables the district judge to evaluate both the scientific validity of the expert's methodology and the strength of the expert's conclusions."^° Decisions by the Third and Ninth Circuits illustrate this approach and, accordingly, do not share the Supreme Court's praise of ensuring reliable expert testimony through cross-examination of experts.^' Furthermore, these circuit courts began to question whether there was truly a dividing line between an expert's methods and ultimate conclusions.^^ One of the first circuit court opinions questioning the limitations of Dauberfs methodology/conclusion distinction was In re Paoli Railroad Yard PCB Litigation.^^ The Paoli case was instituted by thirty-eight plaintiffs who sought damages related to polychlorinated biphenyls ("PCBs"), which leaked out of transformers at a railroad yard and into the groundwater of several nearby residences.^"* Some plaintiffs sought recovery for physical injuries allegedly caused by their exposure to PCBs.^^ Others sought damages for emotional distress related to their fear of future injury or for a decrease in their property values.^^ Defendants filed a motion in limine to exclude the plaintiffs' expert testimony and the underlying evidence purporting to show the harmful effects of PCBs. The district court excluded all the testimony and underlying evidence 68. /\. 133. Mat 532. 134. Seeid.dXSZl. 135. See id. 1 36. Id. Under this approach, "[t]he expert would not be required to prove, in a step-by-step process, how she got from 'Point A' to 'Point B' as a prerequisite to admissibility ofher testimony. Rather, the court would only review the expert's conclusions 'in their entirety.'" Quentin F. Urquhart, Jr. & Brett A. North, Joiner v. General Electric; The Next Chapter in the Supreme Court 's Handling ofExpert Testimony, FOR THE Def., Sept. 1997, at 9, 13. 137. See Joiner, 78 F.3d at 532. 366 INDIANA LAW REVIEW [Vol. 33:349 Judge Barkett further posited that the appropriate "question is whether the expert's use of these studies to help formulate an opinion is methodologically sound."'^^ A judge's gatekeeping role "is not to weigh or choose between conflicting scientific opinions, or to analyze and study the science in question in order to reach its own scientific conclusions."'^^ Rather, a judge's role is "to assure that an expert's opinions are based on relevant scientific methods, processes, and data, and not on mere speculation, and that they apply to the facts at issue."''*^ After applying her view of the district court's gatekeeping role. Judge Barkett concluded that the plaintiffs' expert testimony should have been admitted because it was relevant to establish whether exposure to PCBs caused Joiner's cancer.'"*' Therefore, the Eleventh Circuit Court of Appeals concluded that all ofthe plaintiffs' expert testimony was admissible and reversed the grant of summary judgment by the district court. '"^^ However, Judge Edward Smith disagreed with the majority's decision to admit the expert testimony and wrote a dissenting opinion that provides insight into the Supreme Court's opinion in the subsequent appeal. Judge Smith explained that under Daubert's reliability prong, a district court judge must evaluate "each step in the expert's analysis all the way through the step that connects the work ofthe expert to the particular case.""*^ He further articulated that: [A]n expert's testimony does not "assist" the trier of fact if the expert does not explain the steps he took to reach his conclusion. We should not require the trier of fact to accept blindly the expert's word to fill the analytical gap between proffered "scientific knowledge" and the expert's conclusions. Therefore, the trial court "gatekeeper" has broad discretion to decide whether a leap offaith across the analytical gap is so great that, without further credible grounds, the testimony is inadmissible. "''* Thus, Judge Smith wrote in support of the "admissibility approach" to expert testimony determinations when he stated "[i]t is incumbent on the proponent of scientific evidence to fill the analytical gap between a proffered study and the particular facts of the case (i.e., Tit').""*^ 138. Id. 1 39. Id. at 530. It is improper for a district court to exclude expert testimony when the court would draw a different conclusion from the proffered evidence than the conclusion rendered by the expert. See Conning the lADC Newsletters, 65 Def. Couns. J. 434, 441 (1998). 140. Joiner, 78 F.3d at 530; Roisman, supra note 5, at 567. 141. See Joiner, 7SF.3d at 533-34. 142. See id. Qi 534. 143. Id. at 537 (Smith, J., dissenting) (quoting In re Paoli, 35 F.3d 717, 743, 745 (3d Cir. 1994)). Judge Smith expressed his approval of the trial court's step-by-step approach and stated that he cautions "against using the majority's approach that applies each Daubert prong to the testimony as a whole." Id. at 540. 144. /^. at 535. 145. /flf.at539(quotingDaubertv.MerrellDowPharm.Inc.,509U.S.579,593n.lO(1993)). 1 999] ADMISSIBILITY OF EXPERT TESTIMONY 367 Using this approach, Judge Smith challenged the circuit court's majority decision admitting non-supportive epidemiological studies and the majority's claims that the district court impermissibly delved into the correctness of the experts' conclusions.''*^ He explained that the district court was not determining whether the expert opinions were correct, but whether the animal studies "fit" the facts of the case.'"*^ Therefore, he found no abuse of discretion in the district court's exclusion of the plaintiffs' expert testimony.''*^ In fact. Judge Smith's dissenting opinion provided a detailed analysis ofhis concerns with the Eleventh Circuit's approach to admissibility determinations. The Supreme Court's review of this case recognized persuasiveness of the Smith dissent. B. Appeal to the Supreme Court The Supreme Court granted certiorari in General Electric Co. v. Joiner^^'^ specifically to decide the proper standard ofreview with respect to a trial court's decision regarding the admissibility of expert testimony. '^° However, many commentators viewed it as an important opportunity to revisit Dauberfs methodology/conclusion distinction and the scope of a district court judge's authority with respect to expert testimony.'^' The arguments propounded by the petitioners (PCB manufacturers) and respondents (Joiner) provide insight as to the concerns and arguments for both the weight-of-the-evidence and admissibility approaches. The petitioners argued in favor ofthe admissibility approach and for a more expanded "gatekeeping" role for district court judges. The petitioners asserted that the court of appeals incorrectly "held that if an expert cites conventional scientific authorities, the expert has satisfied the requirement of scientific methodology, no matter what the authorities actually say, and what steps are missing between the citations and the conclusion."'^^ In other words, the declaration approach taken by the court ofappeals showed great deference to the experts' own that their testimony constituted sufficient "scientific knowledge" According to Judge Smith, "an expert may not bombard the court with innumerable studies and then, with blue smoke and slight of hand, leap to the conclusion." Id. at 537. 146. See id. ?ii 539. 147. See id. 148. Seeid.dX5^(). 149. General Elec. Co. v. Joiner, 520 U.S. 1 1 14 (1997) (mem.). 150. See General Elec. Co. v. Joiner, 522 U.S. 136, 138-39 (1997). 151. See William M. Sneed, The Ongoing Revolution in Expert Witness Practice: Daubert and the Seventh Circuit, 86 ILL. B.J. 418, 422 (1998) (indicating that "many members of the legal community believed that the case presented an excellent opportunity for the Court to revisit and perhaps scale back Daubert.""y, Urquhart & North, supra note 1 35, at 1 3 (anticipating the Supreme Court's opinion in Joiner on the "question of whether trial courts can properly examine the reasoning behind the expert's conclusions"). 152. Petitioner's Briefat 48, Genera/ £/ec. Co. v. Jomer, 78 F.3d 524 (1 1th Cir. 1996)(No. 96-188). 368 INDIANA LAW REVIEW [Vol. 33:349 that was relevant to the facts of the case.'^^ Petitioners agreed with the district court's decision finding the experts' testimony inadmissible because the testimony relied on inconclusive epidemiological studies and animal studies that subjected mice to high dosages of PCBs.'^"^ In support of their argument, petitioners reasoned that "[ujnder Daubert, scientific methodology requires scientific reasoning, which includes as a minimum that conclusions be logically supported by premises,"^^^ and in this case, repeated testing did not give rise to a single study supporting the conclusion that PCBs caused small-cell lung cancer.^^^ Similarly, the American Medical Association as petitioners' amici curiae argued that the district court's gatekeeping role requires a preliminary assessment that the research underlying the expert's testimony was consistent with a reliable scientific methodology and supports the expert's ultimate conclusion. '^^ During oral arguments before the Supreme Court, the petitioners contended that if the gatekeeping role was interpreted too narrowly, Daubertwould essentially be overruled because a court would be required to hold proffered expert testimony admissible if the expert drew a conclusion from a published study conducted according to scientific methodology.'^^ The petitioners further argued that a district court judge's gatekeeping role lacks meaning unless it allows the judge to review whether "there is too great an analytical gap" between the expert's underlying premise(s) and the expert's ultimate conclusion(s).'^^ They claimed that a district court must utilize a "link- by-link" analysis to ensure the reliability, or trustworthiness, of an expert's proffered testimony. '^^ Hence, expert testimony would be submitted to the jury only after the district court is satisfied that the proponent has established the appropriate linkage between the expert's underlying data and the ultimate 1 53. See Urquhart & North, supra note 135, at 13. 1 54. See Anthony Z. Roisman, The Implications o/G.E. v. Joinerfor Admissibility ofExpert Testimony, 84 A.L.I.-A.B.A. 491, 494 (1998). 155. Petitioner's Brief at 48, Joiner (No. 96-188). 156. See id. 157. See American Medical Ass'n Brief as Amicus Curiae in Support of Petitioners at 6, Joiner (No. 96- 1 88). "The district court must consider whether the conclusions to which the expert would testify can, as a matter of good science, be drawn from scientifically-generated data." Id. See also Brief of Amici Curiae The New England Journal of Medicine and Marcia Angell M.D., in Support of Neither Petitioners nor Respondents, Joiner (No. 96-188) (espousing the use of scientists to assist judges in making decisions as to the admissibility of expert testimony); Brief Amici Curiae of Bruce N. Ames et. al, in Support of Petitioners, Joiner (No. 96-188). 158. See United States Supreme Court Official Transcript at *21, Joiner, 522 U.S. 136 (1997), available in 1997 WL 634566 (U.S. Oral Arg.). 159. Mat 22. 160. See Urquhart & North, supra note 135, at 13 (proposing that "district [court] judges should be given the freedom to look behind an expert's facial assertion of 'good science' in ruling on the admissibility of proffered expert testimony."). 1999] ADMISSIBILITY OF EXPERT TESTIMONY 369 conclusion rendered.'^' In contrast to the petitioners' view, the respondents and their amici argued that the petitioners' points ofcontention were issues reserved for thejury because they relate to the "weight" of the proffered evidence/testimony, and not admissibility.'^^ Therefore, "[wjhere opposing experts disagree as to how epidemiological and other data should be interpreted it is for the jury to decide the issue."'^^ The respondents reasoned that Dauhert "made it unmistakably clear that [the district courtjudges'] discretion as gatekeepers does not extend to evaluating the conclusions an expert may draw based on scientifically valid principle or procedure."'^"* Thus, the respondents' amici supported Dauberfs methodology/conclusion distinction,'^^ and contended that the petitioners were falsely led to believe that admissibility under Daubert was dependent upon the expert's conclusion or opinion, '^^ The respondents' view arose from the strong trust ofajury's ability to assess the weight and credibility ofexpert testimony, '^^ and was bolstered by studies of jury performance.'^^ Accordingly, the respondent's amici believed that the petitioners' concern with alleged "gaps" between an expert's proffered testimony and the expert's underlying data should go toward the weight of the testimony and not admissibility.'^^ The respondents contended that the proper tools for ensuring the reliability of expert testimony were that of cross-examination, presentation of contrary evidence, exposing flaws in the scientific methodology or the "underlying scientific knowledge in which the expert's opinion is based.'"'" 161. See id. 162. Roisman, supra note 154, at 494. 163. Brief of Amicus Curiae Trial Lawyers of America in Support of Respondents at *8, Jomer (No. 96-188). 164. Id\ see Brief of Amicus Curiae Trial Lawyers for Public Justice in Support of Respondents at * 12, Joiner (No. 96-188). 165. See Brief of Amicus Curiae in Support of Respondents at 9, Joiner (No 96-1 88); Trial Lawyers for Public Justice Brief at 4, Joiner (No. 96-188). Respondent's amici argued that the petitioners and their amici disregarded the Supreme Court's bright-line distinction that only an expert's methodology should be considered for purposes of determining admissibility. See id. 1 66. See BriefofAmicus Curiae Trial Lawyers for Public Justice in Support of Respondents atl2,yomer(No. 96-188). 167. See Brief of Amicus Curiae Association of Trial Lawyers of America in Support of Respondents at 22, Joiner (No. 96-1 88). 168. See id. at 23 (citing Joe S. Cecil et al.. Citizen Comprehension of Different Issues: Lessonsfrom Civil Jury Trials, 40 Am. U. L. Rev. 727, 744-45 (1991)). 1 69. See Brieffor Ardith Cavallo as Amicus Curiae Suggesting Affirmance at 1 1 , Joiner (No. 96-188) (arguing that the purpose of Rule 702's gatekeeping function is to control courtroom speculation and conjecture). 170. Id. at 1 1. Again, "vigorous cross-examination, presentation of contrary evidence, and careful instruction on the burden of proof are the traditional and appropriate means of attacking shaky but admissible evidence." Id. (citing Daubert v. Merrell Dow Pharm., Inc., 509 U.S. 579, 370 INDIANA LAW REVIEW [Vol. 33:349 Physicians devoted to health problems affecting workers provided an interesting amicus briefon behalfofthe respondents. The physicians opined that the district court disregarded the Supreme Court's directive that admissibility determinations must be consistent with the "liberal thrust ofthe Federal Rules of Evidence," and "should weigh broadly in favor of the proponent of the evidence."'^' Furthermore, the physicians' amicus brief set forth that the plaintiffs' experts utilized the scientifically valid methodology of differential diagnosis'^^ in concluding that PCBs could cause Joiner's type of lung cancer. '^^ The physicians' amici briefcontended that the plaintiffs' physician-experts were not required, under Georgia law, to prove that PCBs were the "sole, primary or initiating cause"^^"^ ofJoiner's cancer. In contrast, the experts merely needed "to discern whether any other toxic exposure might reasonably have contributed to the early appearance" '^^ of Joiner's lung cancer by a "reasonable degree of medical certainty."*^^ As a result, the physicians believed that the district court was incorrect in its assessment and understanding ofthe methodologies utilized by medical professionals.'^^ After both sides had the opportunity to present their written briefs and oral arguments on October 14, 1997, it appears the Supreme Court was most persuaded by the position argued by the petitioners. Transcripts from the oral argument indicate that the Court believed the district court was correct in finding that the underlying methodology proffered by the plaintiffs' experts was not sufficient to predicate a conclusion about the cause of cancer in humans. '^^ 596(1993)). 171. Brief of Peter Orris, David Ozonoff, Janet S. Weiss and OCAW (Oil, Chemical, & Atomic Workers Intl. Union, AFL-CIO), as Amici Curiae in Support of Respondents at *6, Joiner (No. 96-188) (citing Daubert, 509 U.S. at 587). This preference of admissibility is derived from the possibility for reasonable experts to arrive at "diametrically opposed conclusions." Id. at *5 n.6. 1 72. Differential diagnosis is defined as "[t]he method by which a physician determines what disease process has caused a patient's symptoms. The physician considers all relevant potential causes of the symptoms and then eliminates alternative causes based on a physical examination, clinical tests, and a thorough case history." Id. at * 1 (citing Reference Manual, supra note 27, at 214). 173. See id. 1 74. M at * 1 4 n. 1 4 (quoting Parrott v. Chatham County Hosp. Auth., 1 45 Ga. App.2d 269, 270 (Ga. Ct. App. 1978); Wells v. Ortho Pharm. Corp., 788 F.2d 741, 743 (1 1th Cir.), cert, denied, 479 U.S. 950(1986)). 175. M at*14. 176. /c/. at*14n.l4. 177. Seeid.dX*\. 1 78. See United States Supreme Court Official Transcript at +52, Joiner, 522 U.S. 1 36 (U.S. 1997), available in 1997 WL 634566 (U.S. Oral Arg.), 66 USLW 3321. The Supreme Court posited: Maybe the district court was saying the methodology is fine for what it purports to do. But it does not provide a sufficient predicate for use in reasoning to a conclusion about cause in humans. Maybe that's what the district court was doing. And if it was doing 1999] ADMISSIBILITY OF EXPERT TESTIMONY 371 Specifically, the Court was not convinced tiiat the weight-of-the-evidence approach would ensure reliability because an expert could pass the threshold of admissibility by stating that he reviewed all available evidence prior to making his ultimate conclusiori.'^^ As a result, the Court responded that Dauberfs methodology/conclusion distinction might be nothing more than a diversion. '^° C The Supreme Court 's Decision The Supreme Court's opinion provided important guidance and clarification as to the extent and scope of a judge's gatekeeping role when determining the admissibility of an expert's opinion.'^' Upon concluding that an abuse of discretion standard governs the review of a lower court's exclusion of expert testimony, ^^^ the majority found error with the court ofappeals' overly stringent review of the district court's decision excluding Joiner's expert testimony. '^^ Therefore, the Court began with a discussion of the problems underlying causational expert testimony based on the analysis of animal and existing epidemiological studies. The Court first addressed the animal studies and found that the plaintiffs' experts failed to explain why they based their opinions on studies utilizing mice injected with massive doses ofPCBs.'^"* Additionally, the experts did not explain why no other study demonstrated an incidence ofcancer due to PCB exposure in humans. '^^ The Court stated that "[t]he issue was whether these experts' opinions were sufficiently supported by the animal studies on which they purported to rely,"'*^ not the validity of using of animal studies. '^^ Based on the that, it seems to me, number one, that it was not committing any legal error. And, number two, it was making a judgment, ultimately, about what the jury could find helpful that should be subject to abuse of discretion view. Id. 179. Seeid.dX*5A. 1 80. See id. In response to Respondent's argument that Daubert merely requires the district court to decide whether the bases supporting the expert's conclusion are reliable, the Court stated that "maybe the methodology prong is just a red herring." Id. 181. See Neal, supra note 5, at 35 n.39 (stating that "the real issue that the defendants wanted the Supreme Court to consider and clarify was whether a district court could look at the conclusions that the expert had reached as well as the methodology."). 182. "Abuse of discretion—^the standard ordinarily applicable to review of evidentiary findings—is the proper standard by which to review a district court's decision to admit or exclude expert scientific evidence." Joiner, 522 U.S. at 138-39. See Marlin, supra note 14, at 142-43 (providing an overview ofthe standard ofreview applied to the admissibility ofscientific testimony prior to the Supreme Court's decision in Joiner). 183. See Joiner, 522 U.S. at 143. 184. SeeiddXXU. 185. Seeid.dXU^'AS. 186. /c/. at 144. 187. See id. 372 INDIANA LAW REVIEW [Vol. 33:349 facts ofthis case, however, the Court found no abuse of discretion by the district court's decision rejecting the animal studies as an insufficient basis of establishing causation in humans.'^* Next, the Court discussed the reliability and relevance ofthe epidemiological studies underlying the expert's causation testimony. The majority found no legal error in the district court's decision "because it 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 that Joiner's exposure to PCB's contributed to his cancer."'^^ Thus, the Supreme Court was not expressly rejecting the weight-of-the-evidence approach as an acceptable methodology.'^^ To illustrate this point, the majority individually analyzed the admissibility of four epidemiological studies used by the petitioners' experts to derive their opinions and found that none of the studies "concluded" that PCB exposure increased the risk of cancer or that Joiner's cancer was aggravated by his exposure to PCBs.'^' After the Court reviewed each ofthe four studies, the majority disagreed with the petitioners' reliance on Dauberfs bright-line distinction requiring judges to remain focused on the expert's methodology and not the expert's conclusions.*^^ The majority explained that "conclusions and methodology are not entirely distinct from one another."'^^ The Court further described the difficulty of conforming to Daubert's bright-line distinction as follows: 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 ofthe expert. A court may conclude that there is simply too great an analytical gap between the data and the opinion 188. Seeid,?&\A2>. 189. /^. at 146-47. 1 90. The Court recognized that there might be an argument that the experts' evidence, when taken as a whole, provided support for a conclusion that PCB exposure aggravated the development of Joiner's cancer. See id. at 145-47. However, the court was unwilling to take this approach because the plaintiff failed to offer evidence showing (1) how the studies were analytically linked or (2) the cumulative impact of the studies. See id. 191. Id. The first study involved Italian workers exposed to PCBs reporting an increased incidence of lung cancer, but found no causal connection between the exposure and death from cancer. See id. at 145. The second study reported an increased incidence of lung cancer deaths at a defendant's PCB production plant, but no causal link between the exposure to PCBs and the increased number of lung cancer deaths. See id. The third study involved Norwegian cable company workers exposed to mineral oil, not PCBs. See id. at 145-46. The fourth study was inconclusive because it involved Japanese workers who were exposed to numerous potential carcinogens (by the ingestion of toxic rice oil) in addition to PCBs. See id. 192. Seeid.dXH6. 193. Id 1999] ADMISSIBILITY OF EXPERT TESTIMONY 373 proffered.'^'* According to the Court, any expert testimony, such as the petitioners' expert testimony, which interprets existing studies or data should not be adm itted based on the bare assertion ofan authority figure. '^^ Consequently, the majority found no reversible error in the district court's decision and decided that "it was in the District Court's discretion to conclude that the studies upon which the experts relied were not sufficient ... to support their conclusions"'^^ with respect to the cause of Joiner's cancer. '^^ 7. Justice Breyer 's Concurrence.—^Justice Breyer's short concurring opinion placed emphasis on Dauberfs statement that trial judges must act as gatekeepers to ensure the reliability and relevance ofall scientific testimony and evidence. '^^ He cautioned that judges must exercise special care in making admissibility determinations because the gatekeeping requirement may often require judges to make subtle and sophisticated determinations about scientific methodology and its relation to the conclusions an expert witness seeks to offer—particularly when a case arises in an area where the science itself is tentative or uncertain, or where testimony about general risk levels in human beings or animals is offered to prove individual causation.'^' Given this difficult role, Justice Breyer noted that use ofthe pretrial conference under the Federal Rules of Civil Procedure provides a forum to "narrow the scientific issues in dispute."^^ Additionally, he encouraged district courtjudges to use their power to appoint independent experts under FRE 706^^' as a method 194. /c/. (emphasis added). 195. See id. 196. Id. 197. See id. at \ 46-47. 198. See id. at 148 (Breyer, J., concurring). 199. Mat 147-48. 200. Id. at 149. 201 . The use of court appointed experts is governed by FRE 706(a), which provides: The court may on its own motion or on the motion of any party enter an order to show cause why expert witnesses should not be appointed, and may request the parties to submit nominations. The court may appoint expert witnesses agreed upon by the parties, and may appoint expert witnesses of its own selection. An expert witness shall not be appointed by the court unless the witness consents to act. A witness so appointed shall be informed of the witness' duties by the court in writing, a copy of which shall be filed with the clerk, or at a conference in which the parties shall have opportunity to participate. A witness so appointed shall advise the parties of the witness' findings, if any; the witness' deposition may be taken by any party; and the witness may be called to testify by the court or any party. The witness shall be subject to cross-examination by each party, including a party calling the witness. Fed. R. Evid. 706(a). 374 INDIANA LAW REVIEW [Vol. 33:349 of facilitating the court's task of determining the admissibility of scientific evidence and testimony.^^^ 2. Justice Stevens ' Partial Concurrence.—^Justice Stevens concurred with the majority's ruling regarding the proper standard ofreview, but dissented with the majority's holding that the testimony of the plaintiffs expert witnesses was inadmissible.^"^ He would have remanded the matter to the court of appeals.^"'* Stevens agreed with the Eleventh Circuit's determination that the evidence of exposure created an issue of fact.^°^ He was unpersuaded by the majority's statement that "'conclusions and methodology are not entirely distinct from one another, '"^"^ and found the court ofappeals' opinion persuasive in its acceptance of the "weight of the evidence"^"^ approach as a scientifically acceptable methodology.^"^ Justice Stevens also found error in the district court's conclusion that no study, by itself, was sufficient to establish a link between PCBs and the plaintiffs onset of lung cancer.^"^ He opined that the district court judge's individual examination of each of the studies led the judge to focus on the experts' conclusions, and not on the underlying methodology.^'" In support of his dissent. Justice Stevens wrote that "[i]t is not intrinsically 'unscientific' for experienced professionals to arrive at a conclusion by weighing all available scientific evidence—^this is not the sort of 'junk science' with which Daubert was concerned."^" He further stated that the district court's position of prohibiting experts from arriving at a conclusion by weighing all scientific evidence is contrary to the same methodology used by the Environmental Protection Agency ("EPA") to assess risks.^'^ Furthermore, he found "nothing in either Daubert or the Federal Rules of Evidence requires a district judge to reject an expert's conclusions and keep them from thejury when they fit the facts of the case and are based on reliable scientific methodology."^'^ Thus, Justice Stevens did not understand why the experts' opinions were inadmissible since the proffered opinions were not based on a single study, but on the combined weight of all available evidence—a methodology applied by the federal government.^ '"* Consequently, he found that the plaintiffs experts could reasonably infer that PCBs could promote lung cancer if the experts were allowed to combine the 202. See Joiner, 522 U.S. at 149 (Breyer J., concurring). 203. See id. at 150-51 (Stevens, J., concurring in part and dissenting in part). 204. See id. 205. Seeid.2A\52. 206. /^. at 155. 207. /^. at 153. 208. See id 209. Seeid2X\5A 210. Seeid-^XXSlf. 211. Id 2 1 2. See id. (citing Brief for Respondents at 40-4 1 , Joiner (No. 96- 1 88)). 213. Id. dX\55. 214. See id 1999] ADMISSIBILITY OF EXPERT TESTIMONY 375 results of various studies under the weight-of-the-evidence approach.^'^ III. The Effect OF Jo/7V£/? A. The Methodology/Conclusion Distinction Remains Even though commentators disagree as to whether the Supreme Court's decision in Joiner resolved the circuit court split regarding the methodology/conclusion distinction,^'^ the Joiner decision clearly represents a retreat from Daubert's strict focus on methodology.^'^ The Supreme Court's opinion reemphasizes that expert testimony proffered in a post-Joiner environment must also satisfy Dauberfs second prong, which requires that evidence be "sufficiently tied to the facts of the case"^'^ by a valid scientific connection.^'^ In short, the expert testimony must "assist the trier of fact to 215. See id. 216. One commentator believes that the majority opinion in Joiner can be construed as allowing "district courts to exclude evidence whenever they disagree with the inductive reasoning by which the expert employing that methodology arrived at his or her conclusion about the probability ofcausation." Gottesman, supra note 1, at 772. Others agree with this proposition and state X\idX Joiner marked a retreat from the Supreme Court's previously strict focus on methodology under Daubert, thus, expanding the scope of the district court judge's authority to include the expert's conclusions. See, e.g., Neal, supra note 5, at 37 (opining that aftQr Joiner, a "district court [can] assess whether the conclusions that the expert purports to reach are supported by the underlying evidence."); Bruce R. Parker, Understanding Epidemiology and Its Use in Drug and Medical Device Litigation, 65 Def. Couns. J. 35, 61 (1998) (indicating in its addendum that the Supreme Court's decision in Joiner "re-emphasizes that a trial court is required, as part of its gatekeeping role, to evaluate not only the methodology used by an expert, but also whether the expert's conclusion[s] meet Daubert standards"); Preuss, supra note 2, at 323 (stating that Joiner clarifies that an expert's methodologies and conclusions are subject to review). However, at least one commentator disagrees with such an expansive reading of the Joiner decision. See Roisman, supra note 154, at 497 (stating that the Joiner decision does not effect Daubert' s admonition that a trial court's preliminary admissibility determination of expert testimony should focus on the expert's methods and not on the ultimate conclusions rendered). 2 1 7. See Graham v. Playtex Prods., Inc., 993 F. Supp. 1 27, 1 32 (N.D.N.Y. 1 998) (noting that with Joiner decision, "the Supreme Court seems to have retreated from this strict focus on methodology alone."). 218. Daubert v. Merrell Dow Pharm., Inc., 509 U.S. 579, 591 (1993). 219. See id. at 592. The Daubert court provided the following example: The study of the phases of the moon, for example, may provide valid scientific "knowledge" about whether a certain night was dark, and if darkness is a fact in issue, the knowledge will assist the trier of fact. However, (absent creditable grounds supporting such a link), evidence that the moon was full on a certain night will not assist the trier of fact in determining whether an individual was unusually likely to have behaved irrationally on that night. Id. 2ii59\. 376 INDIANA LAW REVIEW [Vol. 33:349 understand or determine a fact in issue."^^° The Court was simply reminding judges that there are limits to the admissibility of scientific evidence under the Federal Rules of Evidence.^^' A district court judge must still focus on the expert's methodology,^^^ and therefore, the Joiner decision did remove what the Supreme Court previously established in Daubert. The Joiner decision, however, failed to clarify which methodology a scientific expert can rely upon to establish a "valid scientific connection." Specifically, the Supreme Court did not expressly declare that an expert can rely on the weight-of-the-evidence approach as a reliable methodology.^^^ The majority merely mentioned that it found no error in assessing the reliability of expert conclusions either "individually or in combination."^^"* As a result, the Court did not authorize or deny the reliability of a particular approach. The Court, nevertheless, found that the weight-of-the evidence approach lacked reliability under the Joiner circumstances because the Court apparently excluded the plaintiffs' studies on an individual basis instead of examining the data as a whole. This reasoning appears to form the basis of why the Court ultimately agreed with the district court's decision excluding the plaintiffs' expert testimony.^^^ In response to the post-Jo/wer ambivalence regarding the admissibility of expert testimony, the Judicial Conference Advisory Committee proposed amendments to PRE 702.^^^ As proposed, PRE 702 would read: Ifscientific, 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 provided that (1) the testimony is sufficiently based upon reliable facts or data, (2) the testimony is the product of reliable principles and methods, and (3) the witness has applied the principles and methods 220. Id. A district courtjudge must also focus on the fitness of"[the] experts' testimony and the data from which they draw their conclusions." Marlin, supra note 14, at 149. 221. See Marlin, supra note 14, at 148. 222. The Joiner decision does not effect Daubert' s requirement that ajudge should focus on the expert's methods and not on the ultimate conclusions rendered. See Roisman, supra note 1 54, at 497. 223 . See Gottesman, supra note 1 , at 77 1 -72. 224. General Elec. Co. v. Joiner, 522 U.S. 136, 147 (1997). 225. The Court provided that: [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 that Joiner's exposure to PCBs contributed to his cancer, the District Court did not abuse its discretion in excluding their testimony. Id. at 146-47. 226. See Daniel J. Capra, Corporate Brief: Evidence Amendments, Nat'L L.J., Oct. 5, 1 998, atB-U. 1999] ADMISSIBILITY OF EXPERT TESTIMONY 377 reliably to the facts of the case 227 The proposed amendment language of PRE 702 was intentionally written to apply to both scientific and non-scientific expert testimony.^^^ If ratified, the proposed FRE 702 would also clarify post-Joiner ambiguities surrounding Dauberfs famous methodology/conclusion distinction.^^^ The language clearly indicates that the district courtjudge, as the gatekeeper, must review the expert's methodology and the expert's "application ofthat methodology to the facts ofthe case,"^^^ i.e., the expert's conclusion. Furthermore, it appears that the Advisory Committee was particularly persuaded by Judge Edward R. Becker's reasoning in In re Paoli R.R. YardPCB Litigation,^^ ' that "any step that renders the analysis unreliable renders the expert's testimony inadmissible . . . whether the step completely changes a reliable methodology or merely misapplies that methodology."^^^ Thus, the combined effect of the Joiner decision and the recently proposed amendments to FRE 702 illustrate that a district court judge must find the appropriate balance between assessment of the expert's methodology and the expert's ultimate conclusion. Some commentators believe that Joiner's reliance on Daubert's "fitness" requirement may lead to an unfortunate erosion of the jury's factfinding role^^^ and an inappropriate extension of the district court judge's gatekeeping role.^^"* These commentators further contend that there may be an increased incidence of judges excluding "expert evidence solely on the basis ofwhether they think the evidence supports the party's case."^^^ Additionally, they believe that the Joiner decision may serve as a pretext for district court judges who do not believe the expert's testimony^^^ and may extend the judge's scope of review to cover the expert's underlying assumptions and data, as well as, the expert's conclusion.^^^ ThQJoiner decision did not explicitly broaden ajudge's scope ofreview, nor did it not remove Dauberfs methodology/conclusion distinction. The decision in Joiner merely clarified that a district court judge's scope of review does not end with proof of reliability. Since Daubert it is required that all proffered 227. Id. 228. See id. (indicating that the all expert testimony is subject to the trial court's gatekeeping function). 229. See id. 230. Id. 231. 35F.3d717(3dCir. 1994). 232. Id at 745. 233. See White, supra note 2, at 92 234. See Hope After Joiner, N.J. L.J., Mar. 23, 1 998, at 26. 235. Id.; see also Gottesman, supra note 1, at 775 (stating that the Joiner decision "places too much discretion in the hands of district judges and makes the outcomes of toxic tort cases in federal courts turn on the prejudices of the particular judge rather than on principles of law"). 236. See White, supra note 2, at 92. 237. See Sneed, supra note 151, at 422. 378 INDIANA LAW REVIEW [Vol. 33:349 evidence be both reliable and relevant^^^—i.e., will the evidence "assist the trier of fact to understand or determine a fact in issue."^^^ Nevertheless, the Joiner court's reemphasis on the importance of Daubert's "fitness" prong may prove fatal to some products liability and toxic tort claims. B. Joiner 's Effect on Products Liability & Toxic Tort Claims Judges have relied on the Joiner decision to exclude expert testimony in cases where the expert was unable to satisfy Dauberfs "fitness" requirement. There are several different scenarios where expert testimony is excluded in products liability and toxic tort contexts. The plaintiffs expert testimony may be excluded if (1) the expert's conclusion is too far removed from the available scientific knowledge or data or (2) the expert is unable to establish, beyond his own assertions, that he utilized a generally accepted scientific methodology.^'*^ In both products liability and toxic tort cases, a court may exclude expert testimony when the gap between the underlying evidence and the expert's opinion results in an analytical "chasm."^"^^ The expert must prove there is more than temporal proximity between the evidence and the ultimate conclusion rendered.^"*^ A court will question an expert's conclusions that are "ad hoc" or the product ofdeductive reasoning or speculation ifthere is no physical evidence supporting the expert's position.^"*^ 238. See Daubert v. Merrell Dow Pharm., Inc., 509 U.S. 579, 589 (1993). 239. Id. at 593. 240. In Moore v. Ashland Chemical, Inc., 151 F,3d 269 (5th Cir. 1998), cert, denied, 1 19 S. Ct. 1454 (1999), the trial court excluded the plaintiffs expert testimony with respect to causation because the expert was unable to explain his conclusion or cite scientific support for his conclusion. See id. at 279. The court found the expert's assurances that he utilized a generally accepted scientific methodology insufficient, see id. at 276 (citing Daubert v. Merrell-Dow Pharmaceuticals, Inc., 43 F.3d 1311, 1316 (9th Cir. 1 995) (on remand)), the experts' testimony was allowed because the expert "relied substantially on the temporal proximity between the [plaintiffs] exposure and symptoms." Id. at 278. The trial court's exclusion was affirmed on appeal because "the 'analytical gap' between [the expert's] causation opinion and the scientific knowledge and available data advanced to support that opinion was too wide." Id. at 279. See also In re Breast Implant Litigation, 1 1 F. Supp.2d 1217 (D. Colo. 1998) (excluding expert testimony necessary to establish the plaintiffs burden of causation because the available epidemiologic evidence failed to establish that breast implants caused the auto-immune diseases alleged). 241. Belofsky v. General Elec. Co., 1 F. Supp.2d 504 (D.C.V.I. 1998) (excluding expert testimony that the defendant-manufacturer's refrigerator door was defectively designed because the expert was unable to explain the discrepancy between her ultimate conclusion and contradictory evidence). 242. See Daubert, 509 U.S. at 589. 243. In Childs v. General Motors Corp., No. CIV.A.95-0331, 1998 WL 414719 (E.D. Pa. July 22, 1 998), the trial court granted the manufacturer's motion in limine prohibiting the plaintiffs expert from testifying that a defect in the seat design caused the front passenger seat of the manufacturer's car to collapse because the expert was unable to show that he relied upon generally 1 999] ADMISSIBILITY OF EXPERT TESTIMONY 379 Accordingly, for a products liability or toxic tort claim to survive the scrutiny of both Daubert and Joiner, there must be a nexus between the scientific evidence and the pertinent inquiry of the case. The requisite nexus is often difficult for the plaintiff to establish when the experts are unable to prove that their test results would remain the same if they used humans.^'*'* An expert's inability to replicate the test results using humans will not prove fatal to the admission of expert testimony, so long as the expert can explain her testing procedures and the test results were subjected to peer review in a published study.''' Nevertheless, an expert's ability to explain her scientifically reliable methodology may prove somewhat futile in the context of a novel opinion because the expert must still overcome the issue of "fitness." A toxic tort or products liability expert will fail the "fitness" requirement ifthe expert's opinion is unable to reference the requisite causational link to the facts of a particular case.'"^^ This may prove particularly true in situations where the expert's opinion is based primarily upon the evaluation of animal studies, the impact of cumulative studies, and statistical analysis. As a result, the exclusion of such testimony could effectively preclude legally adequate products liability or toxic accepted methodologies. See id. at *2. The exclusion was supported by the fact that there was no physical evidence supporting the expert's proposition and the expert's theory could not be replicated. See id. dX*A. 5ee a/jo Uribe v. Sofamor, 1999 WL 1129703, at* 12 (D. Neb. Aug. 16, 1999) (excluding medical causation testimony that was unsupported by scientific literature or research conducted independent of the litigation as too speculative and conclusory); Comer v. American Elec. Power, 63 F. Supp.2d 927, 931-34 (N.D. Ind. 1999) (excluding an electrical engineer's testimony in a product liability action against an electrical utility because fire damage due to defective wiring was "not based on any particular evidence or trained observation but represents mere subjective beliefand unsupported speculation"); Hartwell v. Danek Med., Inc., 47 F. Supp.2d 703, 710-16 (W.D. Va. 1 999) (excluding expert medical testimony as merely conclusory in its assertion that a spinal fixation device was the cause of the plaintiffs injuries, and thus precluding the plaintiffs product liability claim). 244. In Lytle v. Ford Motor Co. , 696 N.E.2d 465 (Ind. Ct. App. 1 998), the Indiana Court of Appeals excluded expert testimony that a defect in the defendant's seat belt caused the plaintiffs wife to be thrown from the defendant's truck during a collision. The expert's testimony was unreliable, under the combined criteria of Daubert and Joiner, because the expert was unable to prove that his underlying pendulum test, "hitting the back of a suspended buckle with a small hammer with sufficient force to cause the buckle to inertially release," id. at 467 n.2, results would remain the same ifhe used testing method more similar to the forces present in a real world accident (crash test dummy). See id. at 472-73. 245. See Graham v. Playtex Prods., Inc., 993 F. Supp. 127, 132 (N.D.N.Y. 1998) (admitting expert testimony that the defendant-manufacturer's use ofrayon fibers in the defendant's tampons increased the risk of toxic shock syndrom because the court was not persuaded that the lack of epidemiological data in support of the expert's conclusions gave rise to a significant "analytical gap" requiring exclusion). 246. Barry, supra note 1, at 305. See Gottesman, supra note 1, at 769 ("Introduction of scientific evidence in toxic tort litigation to prove causal relationships is inherently problematic"). 380 INDIANA LAW REVIEW [Vol. 33:349 tort cases from reachingjuries, who may reasonably find in favor ofthe plaintiff. Such a plaintiff may therefore be unable to maintain a cause of action, survive a motion to dismiss or a motion for summary judgment. IV. A LOOK INTO THE FUTURE OF EXPERT TESTIMONY Although the true effects ofthe Joiner decision remain open to debate,^"*^ the Supreme Court's departure from DauberVs bright-line distinction is likely to make the admissibility of expert testimony more restrictive,^'*^ as well as burdensome for the plaintiff. The Supreme Court's reemphasis on "fitness" may affect procedural matters relating to expert testimony and will require lawyers to spend additional time preparing their experts.^"*^ An expert's opinion that something is responsible for the cause of the plaintiffs injuries (i.e., specific causation) will be deemed irrelevant un^Qv Dauberf s fitness prong if an expert is unable to establish proof of general causation.^^^ In products liability or toxic tort claims, the expert must be able to reference data that establishes the relationship between the cause and injury by a preponderance of the evidence before she can opine that the particular item was responsible for the claimant's injuries.^^' Ifan expert is unable to satisfy this burden, a district courtjudge may find that the testimony fails Dauberfs "fitness" requirement because the testimony would be confusing and unhelpful to the jury.^^^ Thus, "the lawyer must be sure that the expert will be able to rationally 247. See supra note 215. 248. See Sneed, supra note 151, at 422 (stating that Joiner decision language undermines Dauberfs liberal approach to the admission of expert testimony). 249. Experts must be prepared to write detailed reports supporting their conclusions and lawyers must be prepared to spend additional time with experts to ensure the expert's ability to explain his reasoning. See Roisman, supra note 154, at 501. 250. In products liability claims, specific causation evidence is admissible only after the expert has established general causation between the product and the plaintiffs injuries. See Raynor v. Merrell Dow Pharm., Inc., 104 F.3d 1371, 1376 (D.C. Cir. 1997) (holding that non- epidemiological studies were insufficient to establish "causation in human beings in the face ofthe overwhelming body of contradictory epidemiological evidence"). 251. The case of In re Breast Implant Litigation, 11 F. Supp.2d 1217 (D. Colo. 1998), excluded plaintiffs' expert testimony in a products liability claim against silicone breast implant manufacturers because their experts were unable to establish general causation, i.e., there was no known, epidemiological study concluding that women with silicone breast implants had at least twice the risk ofdeveloping auto-immune diseases. The court admitted that epidemiological studies are not required because they may often be unavailable. See id. at 1228. However, the expert opinions were scientifically unreliable because none of the expert reports offered supporting data/evidence on general causation that was subject to peer review. See id. at 1229. 252. A district courtjudge should exclude scientific testimony and evidence unless he or she is convinced that it is relevant to a disputed issue of the case and will not confuse or mislead the jury. See id. at 1223 (citing Daubert v. Merrell Dow Pharm., Inc., 43 F.3d 131 1, 1321 (1995) (on remand)). 1999] ADMISSIBILITY OF EXPERT TESTIMONY 381 explain why A causes B in those cases where there is not universal recognition of the conclusions advanced by the expert."^" Furthermore, the expert's explanation must contain "the bases for her conclusions, including . . . why certain evidence supports the ultimate conclusions, in logical and understandable laymen's language, [otherwise,] the Court's [sic] are going to reject such evidence where on its face, or following opposing expert criticism, it seems il logical. "^^'* Therefore, the Joiner decision requires an expert to explain her analysis in a manner establishing the "fitness" ofthe expert's underlying data and her conclusion.^^^ In Joiner's wake, "[tjestifying experts should be prepared to speak the language of Daubert in their depositions, describing the 'methodology' they used, how they tested or otherwise sought to 'falsify' their conclusions or 'hypotheses,' etc."^^^ Ifthe district courtjudge is not satisfied with the expert's explanation or finds the underlying evidence unsupportive of the facts of the case, thejudge can rely on Joiner's authority to exclude the expert's testimony. ^^^ The Joiner decision allows judges to exclude expert testimony "solely on the basis of whether she thinks the evidence supports the party's case."^^^ Thus, lawyers should be prepared to substantiate their claims with expert testimony at the summary judgment stage.^^^ Admittedly, the expansive gatekeeping role propounded in Joiner may keep otherwise valid science from the jury, however, the Supreme Court was aware of this potential risk when the Court set forth the standards governing the admissibility of expert testimony under Daubert?^^ Nevertheless, allowing judges to scrutinize each step of the expert's analysis in support of the expert's conclusion may lead to an increased exclusion oftestimony.^^' The district court 253. Roisman, 5M/7ra note 1 54, at 502. 254. Id. at 491. 255. The Joiner court stressed that a district court must review the legal reliability of an expert's underlying methodology and the expert's conclusions. See Marlin, supra note 14, at 148. ''Joiner, at its most basic level, simply states that experts must explain their analysis sufficiently to overcome any questions of fit between data and conclusion." Id. at 147. 256. Sneed, ^wpranote 151, at423. 257. If the expert is unable to describe or admit that her testimony is a result of a scientific or analytical process, the testimony is likely to be excluded. See id. 258. Hope After Joiner, supra note 234. 259. See Sneed, supra note 1 5 1, at 423 (explaining that lawyers should "[b]e fully prepared by the summary judgment stage, because a significant number of decisions hold expert evidence inadmissible at this point. Affidavits or expert reports under FRCP 26(a)(2) frequently truncate the expert's reasoning or omit the methodology."). 260. The Supreme Court previously noted in Daubert that no matter how flexible a judge's gatekeeping role, it is inevitable that the judge's determinations of admissibility will "prevent the jury from learning of authentic insights and innovations." Daubert v. Merrell Dow Pharm., Inc., 509U.S. 579, 597(1993). 261. Justice Stevens' dissenting opinion in Joiner suggests that if a district court conducts an individual examination of the underlying studies, the court will wrongly focus on the expert's 382 INDIANA LAW REVIEW [Vol. 33:349 judge's expanded gatekeeping role increases the potential for testimonial exclusion when the scientific studies are still developing. The Joiner decision, therefore, further restricted the admissibility ofopinions based upon the weight- of-the-evidence approach that are not exactly "junk science." The Supreme Court has not returned to Frye's general acceptance test; however, the Court has returned to a more restrictive standard governing the admissibility of expert testimony. For novel scientific evidence or testimony to be admissible undtrFrye, the expert's methods need to be generally accepted by the relevant scientific community.^^^ According to the Frye standard, "the thing from which the deduction is made must be sufficiently established to have gained general acceptance in the particular field in which it belongs."^^^ Frye's "general acceptance" test concerned the validity and reliability of the expert's conclusions.^^'* The expert's conclusions were valid ifthey were consistent with the predominant view in the expert's field^^^ and the trial judge determined the expert's conclusions were accurate by weighing the strength of each party's arguments. ^^^ Although Daubert and Joiner do not allowjudges to determine admissibility on the comparative strength of opposing experts, the Joiner decision allows the Supreme Court's desire to combine the benefits of Frye's more restrictive approach to scientific evidence and of Dauberfs reliance on procedural safeguards. Standing alone, the Frye standard focused on the validity of an expert's conclusions. In contrast. Dauberfs two-prong test requires a district courtjudge to focus on the expert's underlying methodology and should favor the introduction ofproffered expert testimony.^^^ The DaubertCourt also viewed the use of cross examination, presentation of contrary evidence, and careful instructions on burden of proof as a better resolution than a wholesale exclusion of expert testimony under Frye's general acceptance test. In Joiner, the Supreme Court appeared to clarify the Daubert opinion and its previous stance on admissibility determinations. Although the Joiner decision did not promulgate a complete return to Frye's general acceptance test, the Court did illustrate support for district court judges to evaluate the "accuracy" of the expert's conclusions by framing emphasis on the "fitness" ofthe proffered expert testimony. The Joiner opinion resembles Frye's emphasis and concern over the validity and reliability of the expert's conclusions. As a result, the Court restricted opportunities for plaintiffs relying on the weight-of-the-evidence approach to pass through a district court judge's admissibility "gates." After Joiner, expert testimony will be submitted to the jury only after the judge is ultimate conclusions. See General Elec. Co. v. Joiner, 522 U.S. 136, 154-55 (1997) (Stevens, J., concurring in part and dissenting in part). 262. See Daubert, 509 U.S. at 585. 263. Id. at 586 (quoting Frye v. United States, 293 F. 1013, 1014 (D.C. Cir. 1923)). 264. See Oh, supra note 13, at 564. 265. See id. 266. See id. 267. See Daubert, 509 U.S. at 596. 1 999] ADMISSIBILITY OF EXPERT TESTIMONY 3 83 satisfied that the plaintiff has established the appropriate linkage between the expert's underlying data and the ultimate conclusion rendered. In the absence of reliable evidence to predicate the expert's ultimate conclusion, the judge may simply conclude "that there is simply too great an analytical gap between the data and the opinion proffered."^^^ Conclusion Dauberfs distinction between conclusions and methods remains important. The Supreme Court'sJo/w^r decision revisited the Court's previous directive and reemphasized the importance of Dauberfs second prong of relevance or "fitness." The consequence oiX\iQ Joiner opinion remains the subject ofdebate. However, various commentators and the proposed amendments to FRE 702 indicate that the Court has returned to heightened standards, thereby preventing the influx of "junk science" into the courtroom, by requiring the trial judge, as gatekeeper, to review the expert's methodology and the expert's application of that methodology to the facts of the case. This heightened level of review may create an insurmountable burden if the plaintiffs expert is unable to prove or sufficiently explain the relevance or reliability of her conclusions. As a result, the viability of many future claims will hinge on the expert's ability to survive the heightened gatekeeping scrutiny established m Joiner. 268. General Elec. Co. v. Joiner, 522 U.S. 136, 146 (1997).