Back in the day, some Circuits of the United States Court of Appeal embraced an asymmetric standard of review of district court decisions concerning the admissibility of expert witness opinion evidence. If the trial court’s decision was to exclude an expert witness, and that exclusion resulted in summary judgment, then the appellate court would take a “hard look” at the trial court’s decision. If the trial court admitted the expert witness’s opinions, and the case proceeded to trial, with opponent of the challenged expert witness losing the verdict, then the appellate court would take a not-so “hard look” the trial court’s decision to admit the opinion. In re Paoli RR Yard PCB Litig., 35 F.3d 717, 750 (3d Cir.1994) (Becker, J.), cert. denied, 115 S.Ct.1253 (1995).
In Kumho Tire, the 11th Circuit followed this asymmetric approach, only to have the Supreme Court reverse and render. Unlike the appellate procedure followed in Daubert, the high Court took the extra step of applying the symmetrical standard of review, presumably for the didactic purpose of showing the 11th Circuit how to engage in appellate review. Carmichael v. Kumho Tire Co., 131 F.3d 1433 (11th Cir. 1997), rev’d sub nom. Kumho Tire Co. v. Carmichael, 526 U.S. 137, 158-59 (1999).
If anything is clear from the Kumho Tire decision, courts do not have discretion to apply an asymmetric standard to their evaluation of a challenge, under Federal Rule of Evidence 702, to a proffered expert witness opinion. Justice Stephen Breyer, in his opinion for the Court, in Kumho Tire, went on to articulate the requirement that trial courts must inquire whether an expert witness ‘‘employs in the courtroom the same level of intellectual rigor that characterizes the practice of an expert in the relevant field.’’ Kumho Tire Co. v. Carmichael, 526 U.S. 137, 152 (1999). Again, trial courts do not have the discretion to abandon this inquiry.
The “same intellectual rigor” test may have some ambiguities that make application difficult. For instance, identifying the “relevant” field or discipline may be contested. Physicians traditionally have not been trained in statistical analyses, yet they produce, and rely extensively upon, clinical research, the proper conduct and interpretation of which requires expertise in study design and data analysis. Is the relevant field biostatistics or internal medicine? Given that the validity and reliability of the relied upon studies come from biostatistics, courts need to acknowledge that the rigor test requires identification of the “appropriate” field — the field that produces the criteria or standards of validity and interpretation.
Justice Breyer did grant that trial courts must have some latitude in determining how to conduct their gatekeeping inquiries. Some cases may call for full-blown hearings and post-hearing proposed findings of fact and conclusions of law; some cases may be easily decided upon the moving papers. Justice Breyer’s grant of “latitude,” however, wanders off target:
“The trial court must have the same kind of latitude in deciding how to test an expert’s reliability, and to decide whether or when special briefing or other proceedings are needed to investigate reliability, as it enjoys when it decides whether that expert’s relevant testimony is reliable. Our opinion in Joiner makes clear that a court of appeals is to apply an abuse-of-discretion standard when it ‛review[s] a trial court’s decision to admit or exclude expert testimony’. 522 U. S. at 138-139. That standard applies as much to the trial court’s decisions about how to determine reliability as to its ultimate conclusion. Otherwise, the trial judge would lack the discretionary authority needed both to avoid unnecessary ‛reliability’ proceedings in ordinary cases where the reliability of an expert’s methods is properly taken for granted, and to require appropriate proceedings in the less usual or more complex cases where cause for questioning the expert’s reliability arises. Indeed, the Rules seek to avoid ‛unjustifiable expense and delay’ as part of their search for ‛truth’ and the ‛jus[t] determin[ation]’ of proceedings. Fed. Rule Evid. 102. Thus, whether Daubert ’s specific factors are, or are not, reasonable measures of reliability in a particular case is a matter that the law grants the trial judge broad latitude to determine. See Joiner, supra, at 143. And the Eleventh Circuit erred insofar as it held to the contrary.”
Kumho, 526 U.S. at 152-53.
Now the segue from discretion to fashion the procedural mechanism for gatekeeping review to discretion to fashion the substantive criteria or standards for determining “intellectual rigor in the relevant field” represents a rather abrupt shift. The leap from discretion to fashion procedure to discretion to fashion substantive criteria of validity has no basis in prior law, in linguistics, or in science. For instance, Justice Breyer would be hard pressed to uphold a trial court’s refusal to consider bias and confounding in assessing whether epidemiologic studies established causality in a given case, notwithstanding the careless language quoted above.
The troubling nature of Justice Breyer’s language did not go unnoticed at the time of the Kumho Tire case. Indeed, three of the Justices in Kumho Tire concurred to clarify:
“I join the opinion of the Court, which makes clear that the discretion it endorses—trial-court discretion in choosing the manner of testing expert 1reliability—is not discretion to abandon the gatekeeping function. I think it worth adding that it is not discretion to perform the function inadequately.”
Kumho Tire Co. v. Carmichael, 526 U.S. 137, 158-59 (1999) (Scalia, J., concurring, with O’Connor, J., and Thomas, J.)
Of course, this language from Kumho Tire really cannot be treated as binding after the statute interpreted, Rule 702, was modified in 2000. The judges of the inferior federal courts have struggled with Rule 702, sometimes more to evade its reach than to perform gatekeeping in an intelligent way. Quotations of passages from cases decided before the statute was amended and revised should be treated with skepticism.
Recently, the Sixth Circuit quoted Justice Breyer’s language about latitude from Kumho Tire, in the Circuit’s decision involving GE Healthcare’s radiographic contrast medium, Omniscan. Decker v. GE Healthcare Inc., 2014 U.S. App. LEXIS 20049, at *29 (6th Cir. Oct. 20, 2014). Although the Decker case is problematic in many ways, the defendant did not challenge general causation between gadolinium and nephrogenic systemic fibrosis, a painful, progressive connective tissue disease, which afflicted the plaintiff. It is unclear exactly what sort of latitude in applying the statute, the Sixth Circuit was hoping to excuse.
