Expert Testimony; Frye Standard: Trial Court as Gatekeeper?

Walsh v. BASF Corp., 191 A.3d 838 (Pa. Super. 2018), allocatur granted March 5, 2019, appeal dockets 14, 15, 16, 17 and 18 WAP 2019

The estate of decedent Thomas Walsh, who had forty-year occupational exposure as a groundskeeper at Pittsburgh area golf courses to chemical manufacturers’ (BASF et al.) pesticides, some of which contained known carcinogens and teratogens, sued BASF et al. alleging that the chemical exposure was a substantial contributing factor to Walsh’s death from Acute Myelogenous Leukemia (AML).

Judge Wettick of the Allegheny County Court of Common Pleas granted summary judgment to BASF et al. based on the standard enunciated in Frye v. United States, 293 F. 1013 (D.C. Cir. 1923).  The substance of the Frye motions was that this case involved novel science, and the methodologies used by Walsh’s experts, epidemiologist April Zambelli-Weiner, Ph.D., and physician Nachman Brautbar, M.D., were not generally accepted or conventionally applied in the relevant scientific communities. The trial court ordered the parties to conduct depositions on the Frye issue. Thereafter, the parties briefed and argued the issues, the trial court granted the Frye motions and excluded the expert testimony, and the parties stipulated to the entry of summary judgment because Walsh’s estate could not prove causation absent the excluded testimony, preserving all rights to appeal the Frye determination.

The Superior Court majority reversed, finding that “the trial court applied its own view of what studies were scientifically/medically acceptable to support the expert’s opinion. In doing so, the trial court impermissibly set itself up ‘as a super expert in the field of medicine.’” Slip Op. at 13-14. President Judge Emeritus Bender dissented, explaining that:

I agree with the trial court that [under Frye] the studies relied on in applying a methodology should be reviewed to confirm that they are cited appropriately. In this case, I believe that the trial court gave adequate reasons for why it found that the cited articles did not support Dr. Brautbar’s conclusions and, consequently, I would not determine that it abused its discretion in precluding the testimony of Appellant’s experts. 

Dis. Op. at 4-5.

As preface to its decision, the Superior Court majority reviewed the basis for the Frye decision, its adoption in Pennsylvania, and its inclusion in Pennsylvania Rule of Evidence 702, concluding:

…the Frye standard originally was intended to prevent a party from introducing scientific evidence that was so new that it would be impossible to “produce rebuttal experts, equally conversant with the mechanics and methods of a particular technique.” Addison, supra at 744. 498 F.2d 741, 744 (D.C. App. 1974). Frye contemplated a judicial inquiry, informed by experts, into the general acceptance of the scientific methods used.

In the years since the adoption of the Frye standard, this Court has clarified that “Frye only applies to determine if the relevant scientific community has generally accepted the principles and methodology the scientist employs, not the conclusions the scientist reaches.” Trach v. Fellin, 817 A.2d 1102, 1112 (Pa.Super. 2003) (en banc). The Frye test has been incorporated into Pennsylvania Rule of Evidence 702, which provides:

A witness who is qualified as an expert by knowledge, skill, experience, training, or education may testify in the form of an opinion or otherwise if:

(a) The expert’s scientific, technical, or other specialized knowledge is beyond that possessed by the average layperson;

(b) The expert’s scientific, technical, or other specialized knowledge will help the trier of fact to understand the evidence or to determine a fact in issue;

(c) The expert’s methodology is generally accepted in the relevant field. Pa.R.E. 702 (emphasis added).

Slip Op. at 7-8.

The majority went on to conclude that Judge Wettick, in applying the Frye analysis, overstepped the role assigned to the court and inappropriately verged into science, assuming the role of gatekeeper and reviewing the scientific studies Walsh’s experts relied on to determine whether the studies actually supported that reliance:

…we find merit in [the Walsh estate’s] contention that the Frye inquiry herein was overly expansive. The court viewed its role as that of a gatekeeper, charged with “review[ing] the studies that Dr. Brautbar relies upon to determine whether they support Dr. Brautbar’s reliance[,]” and “to make sure that the articles stood for what Dr. Brautbar said that they did.” Supplemental Memorandum, 12/27/16, at 5. That is not the proper role of the trial court in a Frye inquiry. Frye requires that a proponent of novel scientific testimony demonstrate that the expert relied upon and conventionally applied a scientific method generally accepted in the relevant scientific community. Both Dr. Brautbar and Dr. Zambelli-Weiner used the Bradford Hill criteria, which the defense agreed was a generally accepted scientific methodology for determining general causation. … [T]he court scrutinized the studies cited by Dr. Brautbar, assessed their scientific relevance and validity, and then arrived at its own conclusion whether the expert’s reliance upon them was scientifically acceptable. The court’s finding that Dr. Brautbar did not follow accepted methodologies in relying upon certain studies in forming his opinions as to general causation added another layer to the generally accepted methodology requirement. Furthermore, the trial court did not identify the methodology it was employing or reference testimony from scientists in the field. In short, the trial court baldly concluded, “Dr. Brautbar’s reliance on this literature to support his general causation theory is not in accordance with generally acceptable scientific methodology.”

Slip Op. at 10-12 (footnotes omitted).

Dissenting, Judge Bender observed that Frye permits the trial judge to inquire into whether the peer-reviewed research the expert relies on actually supports the expert’s opinion:

[T]he trial court reviewed the articles “not for the purpose of reaching its own conclusion regarding causation or to attack Dr. Brautbar’s conclusions[,]” as the Majority suggests, but instead “to evaluate whether [his] cited authorities stand for what they are cited for.” Id. at 5,6. It found that they did not.

Dis. Op. at 2-3.

As an example of the inquiry undertaken by the trial court, the dissent cited this excerpt from the trial court’s opinion:

[U]nder [Appellant’s] position, assume that [Appellant’s expert, Nachman Brautbar, M.D.] concludes that Chemical A causes AML in humans. Also assume Dr. Brautbar supports this conclusion solely by citing an article that concludes Chemical A is completely safe for human exposure. Under [Appellant’s] theory, the [c]ourt may not address the substance of the article, but must accept Dr. Brautbar’s citation and pass the issue on to a jury. Under [Appellant’s] approach, Dr. Brautbar may cite a study regarding traffic patterns in New York City for the proposition that Chemical A causes AML in humans. The [c]ourt may play no role beyond seeing whether Dr. Brautbar cited a study to address a Bradford Hill criterion. Again, according to [Appellant], the [c]ourt must pass the issue on to a jury. Supplemental Memorandum, 12/27/16, at 6.

Dis. Op. at 2.

Multiple defendants sought allocatur of the Superior Court majority’s application of the Frye test, and the Supreme Court has granted allocatur in five petitions.  The issues, as stated by petitioners, are:

(1) Did the Superior Court majority commit reversible error in concluding that, when evaluating scientific evidence under the Frye standard, trial courts are not permitted to act as “gatekeepers” to ensure the relevance and reliability of scientific studies offered by experts to support their opinions by scrutinizing whether those studies actually support their opinions?

(2) Did the Superior Court majority commit reversible error in concluding that trial courts may not review experts’ opinions extrapolating from a broad class of products and injuries to a specific product and injury, thereby eliminating plaintiff’s burden to show product-specific causation of plaintiff’s specific injury?

(3) Did the Superior Court majority commit reversible error in concluding that the trial court erred without explaining how it abused its discretion because of manifest unreasonableness, partiality, prejudice, bias, ill-will or such lack of support from the evidence or the record so as to be clearly erroneous?