Pennsylvania Superior Court Reviews Admissibility of Expert Testimony Based Upon Methodology Behind Opinion

The Pennsylvania Superior Court recently issued a notable decision regarding the admissibility of expert testimony in the case of In the Interest of: M.R., a minor, 2021 Pa. Super. 30 (Pa. Super. March 1, 2021 Bender, P.J.E., Olson, J., and King, J.) (Op. by Bender, J.).

Although this is not a tort case, and involves issues regarding child abuse, the law regarding the admissibility of expert opinions set forth in this decision would likely also apply in civil litigation matters.

At issue in this case was whether the trial court erred and abused its discretion by admitting the testimony of the parents’ expert witness who offered an opinion that metabolic bone disease of infancy (also known as temporary brittle bone disease) was the cause of the twin children’s multiple fractures and not any abuse.

In reviewing the issue of admissibility of the expert’s opinion, the court reviewed Pennsylvania Rule of Evidence 702 and the case of Frye v. United States, 293 F. 1013 (D.C. Cir. 1923).

The court noted that, under Pennsylvania Rule of Evidence 702, which controls the admissibility of expert testimony, one of the requirements for the admission of an expert’s opinion is that the expert’s methodology is generally accepted in the relevant field. This is commonly referred to as the Frye test.

The court noted that the Frye test is limited to an inquiry into whether the methodologies by which the scientist had reached his or her conclusions have been generally accepted in the scientific community. 

The court noted that this test restricts the admission of scientific evidence to that evidence that has resulted from scientific research which has been deemed to be generally recognized as sound research as opposed to the “fanciful creations of a renegade researcher.” [citation omitted].   However, the test is not so restrictive that it does not allow for a scientist to testify as to new conclusions which have emerged during the course of properly conducted research.

Under this test, the proponent of the admission of expert scientific evidence bears the burden of establishing all of the elements supporting its admission, including the general acceptance of a methodology that has actually been employed in the relevant scientific community.

The Pennsylvania Superior Court emphasized that the law of Pennsylvania is that the question of whether a methodology is generally accepted in the relevant scientific community is a determination that is to be made based upon the testimony of scientists in that community and not upon any alleged scientific expertise of the trial court judge. Rather, the Frye test assures that judges will be guided by scientists when assessing the reliability of a scientific method.

As such, under the analysis to be applied in determining whether to admit an expert's opinion, it is the trial court’s function to ensure that the expert has applied a generally accepted scientific methodology to reach his or her scientific conclusions. To fulfill this function, the trial court must be guided by scientists in the relevant field, including the experts retained the parties in the case and any other evidence of general acceptance presented by the parties.  For example, a reference to the methodology in textbooks, scientific publications, studies, statistics, expert testimony, or in other judicial opinions on the issue, or a combination of these sources, can support the admission of an opinion.

The Superior Court cautioned that the trial court may consider only whether the expert applied methodology generally accepted in the relevant field, and the trial court may not go further and attempt to determine whether or not it agrees with the expert’s application of those methodologies and/or whether the expert’s conclusions have sufficient factual support.  Rather, those questions are for a jury to decide.

In setting forth this law, the Pennsylvania Superior Court in this case quoted extensively from the recent Pennsylvania Supreme Court decision in the case of Walsh Estate of Walsh v. BASF Corp., 234 A.3d 446, 456 (Pa. 2020).

In the end, the Pennsylvania Superior Court found that the trial court had abused its discretion by admitting the testimony of the expert in this child abuse case.

Anyone wishing to review a copy of this decision may click this LINK.


I send thanks to Attorney James M. Beck of the Philadelphia office of Reed Smith law firm for bringing this case to my attention.