Expertise in Law, Medicine, and Health Care
Much Ado about Little: The Effect of Daubert, Joiner, and Kumho Tire on Claims of Medical Expertise
Although Daubert arose in the context of a toxic tort claim assessing proffered biomedical evidence, the interpretation of the Federal Rules of Evidence it announced was not explicitly limited to natural science evidence. Joiner and Kumho Tire formally extended Daubert's application to all expert testimony in the federal courts and the state courts that have chosen to follow them. In the courts in which it applies, does Daubert require that medical experts pass a rigorous test of the reliability of their methods and procedures as a condition of admissibility? The answer, at least as reflected in the skewed sample represented by reported decisions (largely appellate cases), is that except in certain contexts, the admissibility of medical expert testimony after Daubert looks much like the admissibility of medical expert testimony before Daubert.
Notwithstanding the call for courts to address claims of medical expertise more rigorously under Daubert, subsequent case law does not reflect that this potential has been realized. As noted above, the reported cases do not reveal opinions scrutinizing the admissibility of "practice guidelines" or science-based medical evidence under Daubert. Indeed, some courts have implied that it is not their task to address such issues. "Daubert neither requires nor empowers trial courts to determine which of several competing scientific theories has the best provenance. It demands only that the proponent of the evidence show that the expert's conclusion has been arrived at in a scientifically sound and methodologically reliable fashion" (DiPetrillo v. Dow Chemical Co., 729 A.2d 677, 690 [R.I. 1999]). Specifically in the context of guidelines, courts have given no hint that different guidelines offered as competing evidence of appropriate practice should be kept from the fact finder.
The evidence shows that reasonable, reputable medical experts do not agree on how often routine mammograms should be performed. The American Cancer Society recommends yearly mammography, while the American College of Obstetricians and Gynecologists recommends "regular" mammography without specifying frequency. If the evidence supports a conclusion that the doctor's only negligence was failure to perform a routine mammogram, then the two schools of thought instruction is appropriate. (Levine v. Rosen, 575 A.2d 579, 582 [Pa. Super. Ct. 1990])
Some, including Chief Justice William H. Rehnquist, question the ability of trial court judges to engage in the Daubert analysis. "I defer to no one in my confidence in federal judges; but I am at a loss to know what is meant when it is said that the scientific status of a theory depends on its 'falsifiability,' and I suspect some of them will be, too" (Daubert, 509 U.S. at 600 [Rehnquist, C.J., concurring and dissenting]). While there is anecdotal evidence of impressive judicial scrutiny of expert testimony applying Daubert as well as anecdotal evidence of less than impressive scrutiny, we have no data for a systemic assessment of the way in which judges have dealt with the issue or what assistance might benefit them. An important step in addressing judicial scrutiny of medical expertise would be a study of this decision-making process in the trial courts.
One area of civil litigation in which there has been a clear and consistent change in the admissibility of medical experts in the wake of Daubert is in toxic tort and products liability cases (Finley 1999). The threshold for the admissibility of medical as well as other types of expertise has risen significantly in this class of cases. Daubert itself aptly illustrates that in these cases being qualified as an expert is no longer an assurance that an expert's testimony will be deemed sufficiently reliable to be admissible. The plaintiff's experts in Daubert, whose testimony was ultimately rejected as unreliable by the court of appeals applying the Supreme Court's new criteria (Daubert v. Merrell Dow Pharmaceuticals, Inc., 43 F.3d 1311 [9th Cir. 1995]), included:
Shanna Helen Swan, who received a master's degree in biostatistics from Columbia University and a doctorate in statistics from the University of California at Berkeley, is chief of the section of the California Department of Health and Services that determines causes of birth defects and has served as a consultant to the World Health Organization, the Food and Drug Administration, and the National Institutes of Health. . . . Stuart A. Newman, who received his bachelor's degree in chemistry from Columbia University and his master's and doctorate in chemistry from the University of Chicago, is a professor at New York Medical College and has spent over a decade studying the effect of chemicals on limb development. . . . The credentials of the others are similarly impressive. (Daubert, 509 U.S. at 583 n.2)
At least in this class of cases, qualifications are no longer a guarantee that the expert's testimony will be deemed sufficiently reliable to be considered by the fact finder.
In medical malpractice litigation, however, the impact of Daubert appears to be more limited. The Frye "general acceptance" gatekeeping test that preceded Daubert had not been regularly applied to expert testimony in medical malpractice cases (Black 1986). Instead, applying the traditional adversarial approach, once the expert was determined to be qualified, the reliability of the expert's methods and procedures was typically left to the jury. Critics of medical malpractice litigation expressed optimism that Daubert would eliminate unreliable expert testimony in these cases (McAbee 1995).
From the few reported cases addressing Daubert's application to standard-of-care issues in medical malpractice cases, no clear pattern of more rigorous scrutiny emerges. Two reported decisions reject outright Daubert's application to standard-of-care issues in medical malpractice cases. The Supreme Court of Montana chose to apply Daubert only to novel scientific evidence and therefore held that it does not apply to the qualification of a physician as an expert on the information that a physician should provide to a patient to obtain informed consent (Gilkey v. Schweitzer, 983 P.2d 869 [Mont. 1999]). The Supreme Court of Washington rejected Daubert's application, holding that a conventional analysis under the rules of evidence was more appropriate because the expert's medical opinion was based on practical experience and acquired knowledge, not a novel scientific procedure (Reese v. Stroh, 907 P.2d 282, 286 [Wash. 1995]). In two other standard-of-care decisions citing Daubert, appellate courts concluded that the trial court had not abused its discretion in the expert testimony it admitted on the standard of care: Carroll v. Morgan (17 F.3d 787 [5th Cir. 1994] [trial court did not abuse discretion under Daubert in refusing to exclude defense expert in medical malpractice case who "refused to recognize any medical textbooks or journal articles as authoritative on endocarditis"]) and Mitchell v. United States (141 F.3d 8 [1st Cir. 1998] [trial court did not abuse discretion under Daubert in admitting expert testimony in medical malpractice case by qualified experts on the standard of care just because witness was not specialist in field in which he gave opinion]). There is little sign that Daubert challenges to admitting expert testimony on the standard of care in medical malpractice cases are likely to be successful so long as lawyers and judges accept testimony as to customary practice7 without demanding methodologically sound survey evidence of its adoption, let alone rigorous proof of efficacy.8 The absence of more demanding threshold scrutiny on this issue appears to result,in large part, from a desire by all parties to enjoy flexibility in framing their cases. Only a mutual willingness to limit that flexibility will result in raising the threshold.
Because the question of causation presents issues that clearly appear to be grounded in science, it might be expected that Daubert would have a more profound effect on causation issues in medical malpractice cases. If Daubert has had any effect on causation issues in reported decisions in medical malpractice cases, it is modest. In two reported medical malpractice cases, appellate courts found that trial courts had abused their discretion in excluding testimony on causation under Daubert.9 Another reported case concluded that there was no abuse of discretion in excluding expert testimony on causation under Daubert in a medical malpractice case (North Dallas Diagnostic Center v. Dewberry, 900 S.W.2d 90 [Tex. Civ. App. 1995]), but another court concluded that there was an abuse of discretion in admitting expert testimony on causation under Daubert in a medical malpractice case (Tanner v. Westbrook, 174 F.3d 542 [5th Cir. 1999]). However, it is far from clear that the decisions relying on Daubert to support exclusion would have reached a different result before that decision (Checchio v. Frankford Hospital, 35 Phila. 53, 35 Pa. D. & C.4th 143 ).
In other categories of civil cases in which psychiatric testimony is frequently presented, such as family law and probate proceedings, there is little indication in the reported cases that Daubert has changed the standard for the admissibility of medical experts (Frolik 1999; Shuman 1997b).
The three cases in which the Supreme Court chose to grant discretionary review to make pronouncements about the trial court's role as a gatekeeper in the admissibility of expert testimony under the Federal Rules of Evidence—Daubert, Joiner, and Kumho Tire—are all civil cases that arise out of toxic tort or products liability claims. A decade before Daubert, the Supreme Court had decided Barefoot v. Estelle (463 U.S. 880 ), a constitutional challenge to the admissibility of psychiatric prediction testimony in a state court capital sentencing proceeding. Embracing a simple relevance standard, Barefoot permitted the introduction of psychiatric testimony labeled unreliable by the expert's peers, the American Psychiatric Association. Daubert, Joiner, and Kumho Tire neither distinguish Barefoot nor limit its application, leaving one to ponder whether they were intended to be applied to criminal litigation. Indeed, the Court's two other decisions involving expert testimony in criminal litigation—Rock v. Arkansas (483 U.S. 44  [rejecting state rule prohibiting admission of defendant's hypnotically refreshed testimony as a violation of the defendant's constitutional right to testify]) and United States v. Scheffer (523 U.S. 303  [Military Rule of Evidence excluding polygraph evidence in court-martial proceedings did not violate defendant's constitutional right to present defense])-have not been a core concern of the Daubert, Joiner, and Kumho Tire trilogy.
Although it might be thought at least as important to avoid erroneous capital punishment or lengthy incarceration as it is to avoid erroneous wealth redistribution, "the 'junk science' debate has all but ignored criminal prosecutions" (Giannelli 1993: 130). There are particular judges (e.g., Judge Jack Weinstein's decisions in United States v. Gigante, 996 F. Supp. 194 [E.D.N.Y. 1997], and United States v. Shonubi, 895 F. Supp. 460 [E.D.N.Y. 1995]) and particular categories of evidence (e.g., State v. Hungerford, 697 A.2d 916 [N.H. 1997] [repressed memory of child sexual abuse claims]) that have yielded demanding scrutiny of medical expertise in criminal cases. However, in the main, it is business as usual for the admission of medical experts in criminal cases after Daubert.
There are no reported Daubert challenges to retrospective psychiatric assessments of criminal responsibility (i.e., the reliability of the methods and procedures used to assess the mental state of a criminal defendant at a time long before the defendant was examined) (Shuman 1996). In addressing the admissibility of expert medical testimony as to cause of death in homicide prosecution, courts ignore the lesson of Daubert and equate the expert's qualifications with the reliability of the expert's methods and procedures.10 Psychiatric prediction of future violence in capital sentencing unsupported by the research continues to be admitted after Daubert (Faigman 1995).
Barriers to a More Informed Application of Science-Based Medical Evidence in Law
Why has the potential that many viewed Daubert to offer not been realized? Specifically what barriers exist to a more informed application of science-based medical evidence in the law? The answer is to be found in core aspects of legal practice and theory. Although Daubert, Joiner, and Kumho Tire may reflect a change in attitude about the trial of toxic tort and products liability actions, they have not changed fundamental attitudes about the admissibility of expert testimony across the legal system for important pragmatic and philosophical reasons.
Pragmatically, the temporal distinctions between law and science that have posed difficult problems for the legal system remain. Indeed, they may be exacerbated by the Daubert trilogy. The legal system's temporal constraints for resolving criminal charges against defendants who may be confined prior to trial or civil compensation claims made by seriously injured plaintiffs are different from the temporal constraints on scientists. "Courts typically do not have the luxury of holding their decisions in abeyance until a body of research develops" (Shuman and Sales 1998: 1247). Daubert's command that courts take science seriously also has temporal consequences. Rigorous independent judicial review of the reliability of the expert's methods and procedures demands more time from an overburdened judiciary. Moreover, it demands a set of skills that are neither required of those who enter the legal profession nor taught as a required part of the law school curriculum.
Lawyers have realized that the same arguments that can be made to exclude their opponent's experts can often be made against their own experts. In some cases, such as family law, lawyers do not typically represent only husbands or wives, plaintiffs or defendants, thus next week they may seek to admit the testimony they challenge today. In other cases where lawyers' roles do not change as readily, such as criminal prosecutions and personal injury litigation, the methods and procedures employed by all of the experts are often surprisingly similar. Thus many lawyers have chosen to attack the credibility of the opposing expert's testimony on cross-examination rather than seeking a ruling that might ultimately result in the exclusion of their own experts. Indeed, in some instances an effective cross-examination of an expert who has utilized an unreliable methodology may be tactically preferable to exclusion of the testimony in its entirety.
Philosophically, many judges have resisted implementation of Daubert as an ill-conceived attempt to reshape the adversary system and the role of the jury in it:
I do not think there is so much of a problem between what was Frye and what is Daubert, but I think Daubert has brought a name to the monster that has really . . . changed the balance of what does and does not go to the jury. That is really troubling to me, to have the gatekeeper be able to say, 'The jury is not even going to get to hear this.' It seems to me to really fundamentally change our whole court system. (Roscoe Pound Foundation 1998: 89)
We have to consider ourselves protectors of the jury system, not guardians for the scientific community and their temporal visions of scientific purity. (Ibid.: 31)
Others have seen the call for a higher admissibility threshold as a problem for the right of litigants, particularly criminal defendants,11 to tell their story that raises constitutional fairness concerns (Slobogin 1998). While still others have argued that although the rules that raise the threshold for the admissibility of expert testimony are facially neutral, they discriminate against certain classes of litigants. For example, by increasing the number and kinds of experts who must be presented to satisfy a Daubert challenge, requiring not only clinicians who perform diagnostic procedures but researchers who can validate these procedures (Jesionowski v. Beck, 955 F. Supp. 149 [D. Mass. 1997]), Daubert increases the cost of litigation, privileging wealthier litigants over poorer litigants, corporations over individuals.
Daubert has not so much changed attitudes about the adversary model as it has reflected one segment of society's long festering dissatisfaction with it, which may explain why the Daubert trilogy has not precipitated a radical transformation of the trial process. For the most part, attitudes about fairness, justice, the adversary system, and use of juries have remained unchanged, so that what appellate courts viewed as a change in the standard for admissibility is often translated in the trial courts into a debate about what weight the jury should give to the evidence.
This experience parallels proposals for the use of court-appointed experts. Although proposals for use of court-appointed experts have long been touted as a solution to problems with retained experts, they have not seen widespread utilization. In the most comprehensive study to date, Joe S. Cecil and Thomas E. Willging (1993) found that court-appointed experts were infrequently used in the federal courts, based in part on the judges' concerns with the potential for interference with the adversary system.
Where Do We Go from Here? Constraints and Concerns
The problems raised in this article are not new, nor is the array of solutions often proposed. Simply reiterating those proposals, such as higher admissibility thresholds and greater use of court-appointed experts, without addressing the reasons for resistance to change, is unlikely to produce a more informed judicial response to claims of expertise in medicine and health care.
There is a widely held perception that raising the reliability threshold for the admissibility of expert testimony is not so much about evidence reform as it is about tort reform, raising barriers for tort plaintiffs (Finley 1999). Apart from undercutting confidence in the impartiality of the judicial process, the decisions that provide support for this perception of a result-oriented jurisprudence undermine the importance of science-based medical evidence for the courts. They suggest that judicial assessments of the science underlying medical expertise matters in some but not all contexts. Any credible attempt to produce a more informed judicial response to claims of medical expertise must address expertise in medicine and health care consistently across the legal spectrum. Reserving rigorous scrutiny of the reliability of medical expertise to narrow classes of cases makes for bad science and bad law.
Many of the problems that courts face in assessing medical expertise are the inevitable result of substantive legal standards. For example, fault-based compensation rules coupled with an absence of national health care or a broad-based social safety net encourages seriously injured individuals to blame others for their injuries to obtain needed financial assistance, guaranteeing that courts will be faced with complex scientific questions for which timely answers will often not exist. Substantive legal standards that call for medical expertise on issues that cannot be operationalized for rigorous study (e.g., the best interests of the child) lead to nonfalsifiable claims of expertise (Shuman 1997b). Any practicable attempt to produce a more informed judicial response to claims of medical expertise must also address the substantive law that often creates a false dichotomy requiring a choice between science and justice. The quality of the answers medical experts provide turns, invariably, on how the legal system frames the questions it asks of experts.
There are many examples of judges' and lawyers' sophisticated applications of Daubert and its state court analogues. There are also many cases that raise important scientific issues in which judges and lawyers either misunderstand the science or avoid the issue and resolve the case on some other legal basis. One apparent explanation for the difference is the education in science that judges and lawyers possess. Any viable attempt to produce a more informed judicial response to claims of medical expertise entails integrating science education into the legal education process, not as an alternative method of satisfying continuing education requirements but as a core aspect of legal education. If lawyers and judges are to be expected to take science seriously, science must be taken seriously in legal education.
Finally, many who advance the gatekeeper model argue that the jury's incapacity to sort out unreliable science necessitates a more rigid threshold for admissibility, while many who oppose this approach do so exactly because they see it as an assault on the right to jury trial. The jury system is fundamental to our democracy by institutionalizing the role of the citizenry in the legal process. It is both unwise and unnecessary to force a confrontation between science and democracy. Any acceptable solutions to assessing claims of medical expertise must include mechanisms for enhancing the reliability of expert testimony without denigrating the jury system.
Ongoing development of medicine as a scientifically grounded practice reveals that the medical profession shares much with the legal profession. Science-based medical evidence and the Daubert trilogy reflect unorchestrated parallel movements in medicine and law about how to assess expertise critically. Although neither has paid any attention to the other, both movements recognize that professional education and training are necessary but not sufficient to assure expertise. Expertise, in the vision of both science-based medical evidence and the Daubert trilogy, begins but does not end with the question of qualifications. A medical expert's qualifications provides no assurance of the reliability of the expert's methods and procedures. Beyond both professions independently drawing this distinction, the impact of distinguishing qualifications and expertise in medicine and law is also of consequence. Why has the recognition of this distinction not transformed the practice of medicine or law?
Science-based medical evidence and the Daubert trilogy reveal much about the nature of both professions. Just as the promulgation of myriad clinical practice guidelines that claim to rest on a critical examination of the medical research literature has not precipitated a sea change in medical practice, so the Daubert trilogy's pronouncements about the admissibility of expert testimony that claims to rest on a critical examination of expertise has not precipitated a sea change in legal practice. The attitudes and beliefs of attorneys about the conduct of trials have not been fundamentally changed overnight by the Daubert trilogy any more than the attitudes and beliefs of physicians about the practice of medicine has been changed overnight by the emergence of clinical practice guidelines. The practices of both professions are determined by myriad intersecting forces that are resistant to sudden change. Charles Darwin's observations about the process of change in natural selection also captures the essence of this process of change in professional practice:
That natural selection generally acts with extreme slowness I fully admit. It can act only when there are places in the natural polity of a district which can be better occupied by the modification of some if its existing inhabitants. The occurrence of such places will often depend on physical changes, which generally take place very slowly, and on the migration of better adapted forms being prevented. . . . But I do believe that natural selection will generally act very slowly, only at long intervals of time, and only on a few of the inhabitants of the same region. (Darwin 1948 : 82)
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