In an end-of-the-summer blockbuster, the Sixth Circuit addressed the “often-elusive line between admissible opinion and inadmissible speculation under Rule 702.” The case could have significant ramifications for products liability cases, particularly in the MDL setting. Not only does this decision overturn a jury verdict of $20.5 million, but it also signals an uphill battle for plaintiffs seeking to rely upon expert testimony to establish causation where the science is unsettled.
In Tamraz v. Lincoln Electric Company (6th Cir., Case No. 08-4015/4016, Sept. 9, 2010) (PDF), the Court held that a physician’s testimony regarding the cause of a disease must be tested under Daubert principles as stringently as the physician’s testimony regarding the diagnosis of the disease. The parties in Tamraz generally agreed that the plaintiff suffered from Parkinson’s Disease, but they did not agree on whether the disease was caused by exposure to manganese during the plaintiff’s career as a welder.
The majority reversed the district court’s admission of the physician’s testimony because some steps in the analysis were supported only by purely theoretical studies and others by unsupported analogies or suppositions. While the Court acknowledged that the “working hypothesis” offered by the expert was “plausible” and “may even be right,” it did not survive Daubert scrutiny because of the “speculative jumps” inherent in the expert’s opinion. What science may view as a “useful but untested hypothesis,” the Sixth Circuit held the law should “generally treat as inadmissible speculation.” The Court expressed concern about “allowing the law to get ahead of science,” a result that “would destroy jobs and stifle innovation unnecessarily.”
Judge Martin’s dissent, which may be the first opinion in the Federal Reporter to cite the TV show “House”, criticized the “majority’s newly-minted requirement that scientific testimony must be without flaws or gaps and have no unprovable inferences or assumptions” as inconsistent with the scientific process. Judge Martin also hinted at a circuit split, arguing that the Second Circuit would treat such matters as questions of weight, rather than admissibility.
Judge Sutton and District Court Judge Reeves (sitting by designation) were in the majority. Judge Martin dissented.