To enforce this standard, the Court directed that it is the gatekeeping function of the trial judge to assure that such testimony is relevant and reliable. Daubert, 509 U.S. at 597. In making this determination, a trial court should consider several factors: (1) whether the particular scientific theory "can be (and has been) tested"; (2) whether the theory "has been subjected to peer review and publication"; (3) the "known or potential rate of error"; (4) the "existence and maintenance of standards controlling the technique's operation"; and (5) whether the technique has achieved "general acceptance" in the relevant scientific or expert community. Daubert, 509 U.S. at 593–94. Though the test is facile in its formulation, the devil is always in the details of application to a particular set of facts.
The Transvaginal Mesh Litigation
The transvaginal mesh multidistrict litigation pending in the Southern District of West Virginia has provided several opportunities for the court to apply the Daubert standards to a variety of experts and proposed testimony. See Eghnayem v. Boston Sci. Corp., 57 F. Supp. 3d 658 (S.D. W. Va. 2014); Tyree v. Boston Sci. Corp., 54 F. Supp. 3d 501 (S.D. W. Va. 2014); Sanchez v. Boston Sci. Corp., No. 2:12-cv-05762, 2014 U.S. Dist. LEXIS 137189 (S.D. W. Va. Sept. 29, 2014). The experts whose opinions and qualifications were evaluated range from engineers to gynecologists. The court's detailed analysis of those experts' qualifications and the substance and reliability of their numerous opinions exemplifies the type of arguments and proofs that should be made in mounting or resisting a Daubert challenge.
State of Mind Testimony Generally
One of the first issues addressed by the court generally was whether an expert could testify, based upon his or her review of internal corporate documents, as to the knowledge or intent of a corporate defendant. Generally rejecting this testimony, the court concluded that "a party's knowledge, state of mind, or other matters related to corporate conduct and ethics are not appropriate subjects of expert testimony because opinions on these matters will not assist the jury." Tyree, 54 F. Supp. 3d at 517–18. Experts may not be utilized to "usurp the jury's fact-finding function." Tyree, 54 F. Supp. 3d at 517.
In addition to this general challenge, specific challenges were made to the qualifications, reliability, and methodology of other experts.
Specific Testimony of Experts
The opinion of the plaintiff's expert, Margolis, was one specifically challenged. Margolis was a pelvic surgeon and urogynecologist and had experience in treating patients suffering complications from prior gynecological surgeries. Sanchez, 2014 U.S. Dist. LEXIS 137189, at *15. Several grounds were asserted for excluding his testimony, including that: (1) he failed to consider contradictory scientific studies in forming some of his opinions, (2) other opinions had no scientific basis, (3) certain opinions were outside his area of expertise, and (4) certain opinions related to the defendant's state of mind. Tyree, 54 F. Supp. 3d at 519.
A recurring issue with any expert is whether he or she considered studies, opinions, or other materials contradicting or impairing his or her analysis and ultimate risk.
Failure to consider contrary studies. In Tyree, Margolis, when presented with contrary studies, rejected them. He testified that he "question[ed] the reliability" of one study but could not explain why the study was not reliable. Tyree, 54 F. Supp. 3d at 520. In sustaining a Daubert objection, the court noted that an expert's opinion may be unreliable "if he fails to account for contrary scientific literature and instead selectively [chooses] his support from the scientific landscape." Tyree, 54 F. Supp. 3d at 520 (internal quotation marks omitted). On the same basis, the court rejected Margolis's opinion that certain devices were not safe and not effective, that complication rates of pain were higher in women who had had certain procedures, and that general complication rates were higher in women with the mesh. Tyree, 54 F. Supp. 3d at 520–21.
The failure to consider other opinions and contrary materials is thus not simply a matter for cross-examination and a closing argument that the expert was biased, but it is a ground for complete exclusion of the testimony for lack of reliability under Daubert.
Lack of scientific basis. Margolis also opined that certain other devices resulted in fewer complications than the mesh device. His opinion was based on his reasoning that because the other device used no mesh then there was no mesh complication. Although this would seem to be discernible by even the most uninformed juror, having an expert say it would tend to increase its importance. However, the court would have none of this puffing. Said the court, "This logic is not scientific" because the same conclusion could be reached by a jury without expert testimony. Tyree, 54 F. Supp. 3d at 523.
Protocols and sample size. A biomedical engineer, Barker, encountered similar Daubert issues when he sought to testify as to the behavior of the mesh inside the human body. Among the various challenges leveled at his testimony, two are of particular interest: failure to follow established protocols and failure to use a sufficient sample size. As to protocols, Barker failed to utilize a saline bath as part of his testing procedures, which element was necessary to replicate the physiological environment of the human body under accepted standard protocols. The failure to follow established protocols resulted in finding the "methodology to be unreliable." Tyree, 54 F. Supp. 3d at 545–46. Barker's opinion was also challenged because of the sample size utilized in his test. Because his sample size (three) was too small, the court found that "it is difficult to predict whether his results were merely chance occurrences. Tyree, 54 F. Supp. 3d at 546–47.
Again these failures or defects could be utilized in cross-examination to challenge the expert's opinion by implication. Here they were successfully utilized to exclude the opinion in its entirety, a much preferable result.
Source and selection of supporting evidence. Another expert on the general pathology of vaginal mesh implantation fared no better. The defendant challenged Trepta's testimony on general grounds, including that it was unreliable because the pathology reports on which he relied were selected by the plaintiff's counsel. The court agreed that Trepta's testimony was unreliable because it "lacked standards to govern the process of selecting the sample pathology report to be evaluated." Tyree, 54 F. Supp. 3d at 530. Recognizing that the selection of certain reports and the exclusion of others could reflect bias, the court concluded "[t]here are no assurances that [plaintiffs' counsel] did not opportunistically choose samples while ignoring others that might have weakened or disproved [the expert's] theories." Tyree, 54 F. Supp. 2d at 530.
Application of protocols. Two other experts, a chemist and an engineer, also ran afoul of Daubert. Mays and Gido offered opinions regarding the polypropylene mesh utilized in the defendant's products. Although numerous challenges were directed to their testimony, two are particularly interesting. Unlike Margolis, these experts utilized accepted testing procedures; however, they did not adhere to the accepted procedures. For example, in cleaning the test samples, one expert used a 6 percent bleach solution and the other used a 7.8 percent concentration. Numerous other examples of inconsistent application of testing procedure were also listed by the court in its evaluation of the testing. The resulting conclusion was that: "Although Drs. Mays and Gido performed tests that are supported by the literature, the haphazard application of these tests, errors, and changes to their report lead to the conclusion that their methodology is unreliable. Vigorous adherence to protocols and controls are the hallmarks of 'good science.'" Eghnayem, 57 F. Supp. 3d at 688. The court also questioned the fact that certain tests and test results were not included in the expert reports, including the bleach concentration difference. The failure of the experts to include complete test results provided an additional ground for the court to conclude that the opinions were unreliable.
Expertise in the particular opinion issued. Although an expert may be qualified in even a very narrow specialty, that does not mean any opinion offered in even that narrow specialty satisfies Daubert. In Eghnayem, Raybon, a board certified physician in obstetrics and gynecology, specializing in female pelvic and reconstructive surgery, sought to testify as to the clinical effects of the mesh in the patient's body, particularly the cause of nerve trauma in the pelvis. The court accepted that Raybon was an expert in the area of pelvic surgery. However, there was no showing that he was an expert in "the etiology of pelvic and vaginal pain." Eghnayem, 57 F. Supp. 3d at 701. Even though his experience in this area of medicine was extensive, it did not qualify him to render an opinion on the narrow issue of the "cause of nerve trauma in the pelvis." Eghnayem, 57 F. Supp. 3d at 701.
Though an expert may be eminently qualified in a general or even a very specific area, that does not mean, for example, any doctor may give an opinion about any medical issue. Eghnayem emphasizes that such a limitation is issue-specific—even a heart surgeon may not testify as to just any opinion involving the heart.
Generally accepted standard: written protocol. Experts sometimes devise their own tests in reaching their opinions. In Eghnayem, Iakovlev, an anatomical pathologist, devised a test to simulate forces acting on the mesh device within the body to support his opinion that the mesh deforms when stretched. Eghnayem, 57 F. Supp. 3d at 709. However, Iakovlev did not establish any standards or written protocols prior to conducting the testing. In excluding his testimony, the court found that the failure to establish a written protocol for the test impaired the test's reliability. The court also concluded there was no evidence that the test the expert developed was "generally accepted in the scientific community." Eghnayem, 57 F. Supp. 3d at 710–11.
Eghnayem cautions counsel that if your expert elects to use his or her own test, it must be properly documented and generally supported by the learning in the particular field of his or her testimony.
The opinions in Eghnayem, Tyree, and Sanchez are extensive, exceeding 250 pages, and include evaluations of numerous experts and their reports not discussed in this article. However, the opinions exemplify a methodology for dissecting and analyzing expert opinions in the minutest detail. Collectively, the opinions provide a checklist for attorneys seeking either to create a bulletproof expert opinion or to limit or exclude an expert opinion, one element at a time.
Keywords: litigation, commercial, business, Daubert, expert opinion, transvaginal mesh multidistrict litigation