                        [J-92A-E-2019][M.O. - Donohue, J.]
                   IN THE SUPREME COURT OF PENNSYLVANIA
                               WESTERN DISTRICT


RICHARD THOMAS WALSH,                  :   No. 14 WAP 2019
EXECUTOR OF THE ESTATE OF              :
THOMAS J. WALSH, DECEASED              :   Appeal from the Order of the Superior
                                       :   Court entered 6/20/18 at No. 1661 WDA
                                       :   2016 vacating the order of the Court of
              v.                       :   Common Pleas of Allegheny County
                                       :   entered 10/14/16 at No. GD 10-018588
                                       :   and remanding
BASF CORPORATION; BAYER                :
CORPORATION D/B/A BAYER                :
CROPSCIENCE, L.P., AND BAYER           :   ARGUED: October 16, 2019
CROPSCIENCE HOLDING, INC.,             :
AND/OR BAYER CROPSCIENCE, L.P.         :
AND BAYER CROPSCIENCE HOLDING,         :
INC., IN THEIR OWN RIGHT; BIOSAFE      :
SYSTEMS, L.L.C.; CHEMTURA              :
CORPORATION; CLEARY CHEMICAL           :
CORP.; DOW AGROSCIENCES, L.L.C.;       :
E.H. GRIFFITH, INC.; E.I. DU PONT DE   :
NEMOURS AND CO., INC.; G.B.            :
BIOSCIENCES CORPORATION; JOHN          :
DEERE LANDSCAPING, INC.,               :
SUCCESSOR TO LESCO, INC.;              :
MONSANTO COMPANY; NUFARM               :
AMERICAS, INC.; REGAL CHEMICAL         :
CO.; SCOTTS-SIERRA CROP                :
PROTECTION CO.; AND SYNGENTA           :
CROP PROTECTION, INC.                  :
                                       :
APPEAL OF: DOW AGROSCIENCES,           :
LLC, BAYER CROPSCIENCE, LP,            :
BAYER CORPORATION, AND BAYER           :
CROPSCIENCE HOLDING, INC.              :



RICHARD THOMAS WALSH,                  :   No. 15 WAP 2019
EXECUTOR OF THE ESTATE OF              :
THOMAS J. WALSH, DECEASED              :   Appeal from the Order of the Superior
                                       :   Court entered 6/20/18 at No. 1661 WDA
                                       :   2016 vacating the order of the Court of
                                       :   Common Pleas of Allegheny County
                                       :   entered 10/14/16 at No. GD 10-018588
              v.                       :   and remanding
                                       :
                                       :
BASF CORPORATION; BAYER                :   ARGUED: October 16, 2019
CORPORATION D/B/A BAYER                :
CROPSCIENCE, L.P., AND BAYER           :
CROPSCIENCE HOLDING, INC.,             :
AND/OR BAYER CROPSCIENCE, L.P.         :
AND BAYER CROPSCIENCE HOLDING,         :
INC., IN THEIR OWN RIGHT; BIOSAFE      :
SYSTEMS, L.L.C.; CHEMTURA              :
CORPORATION; CLEARY CHEMICAL           :
CORP.; DOW AGROSCIENCES, L.L.C.;       :
E.H. GRIFFITH, INC.; E.I. DU PONT DE   :
NEMOURS AND CO., INC.; G.B.            :
BIOSCIENCES CORPORATION; JOHN          :
DEERE LANDSCAPING, INC.,               :
SUCCESSOR TO LESCO, INC.;              :
MONSANTO COMPANY; NUFARM               :
AMERICAS, INC.; REGAL CHEMICAL         :
CO.; SCOTTS-SIERRA CROP                :
PROTECTION CO.; AND SYNGENTA           :
CROP PROTECTION, INC.                  :
                                       :
APPEAL OF: DEERE & COMPANY             :



RICHARD THOMAS WALSH,                  :   No. 16 WAP 2019
EXECUTOR OF THE ESTATE OF              :
THOMAS J. WALSH, DECEASED              :   Appeal from the Order of the Superior
                                       :   Court entered 6/20/18 at No. 1661 WDA
                                       :   2016 vacating the order of the Court of
              v.                       :   Common Pleas of Allegheny County
                                       :   entered 10/14/16 at No. GD 10-018588
                                       :   and remanding
BASF CORPORATION; BAYER                :
CORPORATION D/B/A BAYER                :
CROPSCIENCE, L.P., AND BAYER           :   ARGUED: October 16, 2019
CROPSCIENCE HOLDING, INC.,             :
AND/OR BAYER CROPSCIENCE, L.P.         :
AND BAYER CROPSCIENCE HOLDING,         :
INC., IN THEIR OWN RIGHT; BIOSAFE      :
SYSTEMS, L.L.C.; CHEMTURA              :

                    [J-92A-E-2019][M.O. – Donohue, J.] - 2
CORPORATION; CLEARY CHEMICAL            :
CORP.; DOW AGROSCIENCES, L.L.C.;        :
E.H. GRIFFITH, INC.; E.I. DU PONT DE    :
NEMOURS AND CO., INC.; G.B.             :
BIOSCIENCES CORPORATION; JOHN           :
DEERE LANDSCAPING, INC.,                :
SUCCESSOR TO LESCO, INC.;               :
MONSANTO COMPANY; NUFARM                :
AMERICAS, INC.; REGAL CHEMICAL          :
CO.; SCOTTS-SIERRA CROP                 :
PROTECTION CO.; AND SYNGENTA            :
CROP PROTECTION, INC.                   :
                                        :
APPEAL OF: SYNGENTA CROP                :
PROTECTION, INC.                        :



RICHARD THOMAS WALSH,                   :   No. 17 WAP 2019
EXECUTOR OF THE ESTATE OF               :
THOMAS J. WALSH, DECEASED               :   Appeal from the Order of the Superior
                                        :   Court entered 6/20/18 at No. 1661 WDA
                                        :   2016 vacating the order of the Court of
              v.                        :   Common Pleas of Allegheny County
                                        :   entered 10/14/16 at No. GD 10-018588
                                        :   and remanding
BASF CORPORATION; BAYER                 :
CORPORATION D/B/A BAYER                 :
CROPSCIENCE, L.P., AND BAYER            :   ARGUED: October 16, 2019
CROPSCIENCE HOLDING, INC.,              :
AND/OR BAYER CROPSCIENCE, L.P.          :
AND BAYER CROPSCIENCE HOLDING,          :
INC., IN THEIR OWN RIGHT; BIOSAFE       :
SYSTEMS, L.L.C.; CHEMTURA               :
CORPORATION; CLEARY CHEMICAL            :
CORP.; DOW AGROSCIENCES, L.L.C.;        :
E.H. GRIFFITH, INC.; E.I. DU PONT DE    :
NEMOURS AND CO., INC.; G.B.             :
BIOSCIENCES CORPORATION; JOHN           :
DEERE LANDSCAPING, INC.,                :
SUCCESSOR TO LESCO, INC.;               :
MONSANTO COMPANY; NUFARM                :
AMERICAS, INC.; REGAL CHEMICAL          :
CO.; SCOTTS-SIERRA CROP                 :
PROTECTION CO.; AND SYNGENTA            :
CROP PROTECTION, INC.                   :

                     [J-92A-E-2019][M.O. – Donohue, J.] - 3
                                           :
APPEAL OF: MONSANTO COMPANY                :


RICHARD THOMAS WALSH,                      :   No. 18 WAP 2019
EXECUTOR OF THE ESTATE OF                  :
THOMAS J. WALSH, DECEASED                  :   Appeal from the Order of the Superior
                                           :   Court entered 6/20/18 at No. 1661 WDA
                                           :   2016 vacating the order of the Court of
                v.                         :   Common Pleas of Allegheny County
                                           :   entered 10/14/16 at No. GD 10-018588
                                           :   and remanding
BASF CORPORATION; BAYER                    :
CORPORATION D/B/A BAYER                    :
CROPSCIENCE, L.P., AND BAYER               :   ARGUED: October 16, 2019
CROPSCIENCE HOLDING, INC.,                 :
AND/OR BAYER CROPSCIENCE, L.P.             :
AND BAYER CROPSCIENCE HOLDING,             :
INC., IN THEIR OWN RIGHT; BIOSAFE          :
SYSTEMS, L.L.C.; CHEMTURA                  :
CORPORATION; CLEARY CHEMICAL               :
CORP.; DOW AGROSCIENCES, L.L.C.;           :
E.H. GRIFFITH, INC.; E.I. DU PONT DE       :
NEMOURS AND CO., INC.; G.B.                :
BIOSCIENCES CORPORATION; JOHN              :
DEERE LANDSCAPING, INC.,                   :
SUCCESSOR TO LESCO, INC.;                  :
MONSANTO COMPANY; NUFARM                   :
AMERICAS, INC.; REGAL CHEMICAL             :
CO.; SCOTTS-SIERRA CROP                    :
PROTECTION CO.; AND SYNGENTA               :
CROP PROTECTION, INC.                      :
                                           :
APPEAL OF: BASF CORPORATION                :




                              DISSENTING OPINION


CHIEF JUSTICE SAYLOR                           DECIDED: JULY 21, 2020


      The majority deems it inconsequential whether or not this Court should

denominate trial judges as gatekeepers relative to the admission of novel scientific

                      [J-92A-E-2019][M.O. – Donohue, J.] - 4
evidence in Pennsylvania courtrooms. See Majority Opinion, slip op. at 20. Personally,

however, I find this to be the clear purport of most of this Court’s decisions on the

subject. My response to the majority opinion is set forth below. Since Justice Wecht

has taken the opportunity, from a side position, to respond to my present remarks -- as

well as to criticize the opinion that I authored in Betz v. Pneumo Abex LLC, 615 Pa. 504,

44 A.3d 27 (2012) -- I have also included my reply to his opinion.


                           I. Reply to the Majority Opinion

       On an appropriate motion, trial judges in Pennsylvania bear the obligation to

screen novel scientific evidence for reliability before permitting such evidence to be put

before jurors. See, e.g., Grady v. Frito-Lay, Inc., 576 Pa. 546, 557, 839 A.2d 1038,

1044-45 (2003).     This Court, like most others, has implemented this particular

gatekeeping responsibility in light of the influential nature of expert testimony on

complex subjects and the potential that distortions have to mislead laypersons. See

Betz, 615 Pa. at 544-47, 44 A.3d at 52-54; see also id. at 532 n.15, 44 A.3d at 44 n.15

(quoting a cogent encapsulation by the Honorable Phyllis W. Beck in Blum v. Merrell

Dow Pharms., Inc., 705 A.2d 1314, 1325 (Pa. Super. 1997), aff’d, 564 Pa. 3, 764 A.2d 1

(Pa. 2000)); accord In re Accutane Litig., 191 A.3d 560, 589 (N.J. 2018) (explaining that

“the gatekeeping function prevents the jury’s exposure to unsound science through the

compelling voice of an expert” and “[d]ifficult as it may be, the gatekeeping role must be

rigorous”).

       For these reasons, I have previously expressed the concern that the Frye

standard should not be interposed in a way that deprives trial judges of the ability to

screen expert opinions for sufficient reliability. See Commonwealth v. Smith, 606 Pa.

127, 186, 995 A.2d 1143, 1177 (2010) (Saylor, J., concurring and dissenting) (“[I]f the

Court is going to interpret Frye so narrowly as to justify the admission of speculative

                        [J-92A-E-2019][M.O. – Donohue, J.] - 5
opinions, or opinions falsely couched in scientific literature, I believe the time has come

for Pennsylvania to move to the Daubert standard.”).

       In this regard, to the degree that the majority opinion advocates that the Frye

standard is superior to approaches taken by other courts in the modern litigation

environment, see, e.g., Majority Opinion, slip op. at 17-18, I respectfully disassociate

myself from that view. Accord Grady v. Frito-Lay, Inc., 576 Pa. at 570, 839 A.2d at

1052 (Saylor, J., concurring) (“Concerning the Frye/Daubert debate, I take the position

that the Frye rule is and remains the law of the Commonwealth, unless and until

informed advocacy is presented that would favor a new direction, with due reference to

the substantial body of information that has developed concerning the experience of the

federal courts and others under Daubert.”).       Significantly, I believe that there are

benefits and drawbacks to each of the mainstream approaches, and I would reserve

any assessment of the comparative merits to a setting in which the Court has the

benefit of a developed analysis. See, e.g., Accutane, 191 A.3d at 583-95 (reflecting the

Supreme Court of New Jersey’s recent refinement of the state’s standard governing the

admissibility of novel expert opinions, upon close consideration of the available options).

       In my view, Judge Wettick properly discharged his gatekeeping function in the

present case. Upon review of scientific literature relied upon by Dr. Brautbar, Judge

Wettick found that there were extensive, unexplained analytical gaps between the

expert’s opinions and the material upon which he relied. See Walsh v. BASF Corp., No.

GD-10-018588, slip op. at 2-19 (C.P. Allegheny Oct. 16, 2016); see also Walsh v. BASF

Corp., No. GD-10-018588, slip op. at 2-6 (C.P. Allegheny Dec. 27, 2016). And that

finding is amply supported by the record.




                        [J-92A-E-2019][M.O. – Donohue, J.] - 6
       Indeed, the record support for Judge Wettick’s conclusion includes the testimony

of Dr. Brautbar himself. For example, Dr. Brautbar acknowledged that dose response is

a fundamental tenet of toxicology. See, e.g., See Deposition of Nachman Brautbar,

M.D., dated May 15, 2014 at 836; accord Joseph V. Rodricks, Reference Guide on

Exposure Science, REFERENCE MANUAL         ON   SCIENTIFIC EVIDENCE 507 (Fed. Judicial

Center 3d ed. 2011) (“Ultimately the dose incurred by populations or individuals is the

measure needed by health experts to quantify the risk of toxicity.”). 1 He proceeded,

however, to render opinions about substantial-factor causation relative to Mr. Walsh,

while repeatedly conceding that he was both unable to identify any dose-response

threshold for any of the fourteen products at issue in this case, see, e.g., N.B. at 798,

and that he had no idea of the quantity of the dose experienced by Mr. Walsh for any

particular product, see, e.g., id. at 300-301, 552. At least in many other courts, such

testimony would plainly be regarded as unscientific and insufficient to establish

substantial-factor causation.2

1The deposition of Dr. Brautbar spanned four days, but the pagination for the transcript
was continuous. For convenience, the deposition is referred to hereinafter as “N.B. at
__.”

2 See, e.g., McClain v. Metabolife Int’l, Inc., 401 F.3d 1233, 1241-42 (11th Cir. 2005)
(relating that an expert’s failure to lay a reliable groundwork for assessing the dose-
response relationship in a toxic tort case “signals a methodological problem”); Burleson
v. Tex. Dep’t of Criminal Justice, 393 F.3d 577, 587 (5th Cir. 2004) (highlighting that a
causation opinion where the expert “fail[s] to conduct a dose assessment” produces “too
great an analytical gap between the data and the opinion proffered” (citation omitted));
Mitchell v. Gencorp, Inc., 165 F.3d 778, 781 (10th Cir. 1999) (“[A] plaintiff must
demonstrate the levels of exposure that are hazardous to human beings generally as
well as the plaintiff’s actual level of exposure to the defendant’s toxic substance before
he or she may recover.”); Allen v. Pa. Eng’g Corp., 102 F.3d 194, 199 (5th Cir. 1996)
(“Scientific knowledge of the harmful level of exposure to a chemical, plus knowledge
that the plaintiff was exposed to such quantities, are minimal facts necessary to sustain
the plaintiffs’ burden in a toxic tort case.”); Yates v. Ford Motor Co., 113 F. Supp. 3d
841, 861 (E.D.N.C. 2015) (“Rather than engage in any specific, meaningful comparison
(continued…)
                        [J-92A-E-2019][M.O. – Donohue, J.] - 7
       In this regard, Dr. Brautbar’s notion of substantiality, in terms of the duration of

exposure, doesn’t conform at all to the legal standard, in that he defined the conception

as merely being “not ridiculous, theoretical, or infinitesimal.” Id. at 776. Furthermore,

numerous defense experts highlighted the unscientific nature of Dr. Brautbar’s analysis.

See, e.g., Deposition of Scott D. Phillips, M.D., dated Jan. 12, 2016, at 32 (reflecting the

testimony of a medical toxicologist that Dr. Brautbar’s methodology violated basic

principles of toxicology in that he “simply stated that the dose was sufficient to cause his

AML, which creates a circular logic reasoning kind of pathway”); Deposition of John

Ross, Ph.D., dated Jan. 13, 2016, at 49 (remarking that Dr. Brautbar “repeated over and

over again that it was the proximity, duration and frequency of exposure that allowed

Mr. Walsh to be overexposed without providing a shred of evidence on what those

were.”).3


(…continued)
of the scientific data with [the plaintiff’s] exposures, [the expert’s] opinions essentially
attempt to overwhelm with statistics and studies, lacking guidance as to how a juror
ought to apply them[, which] is not a reliable method, and it will not assist a jury.”).

I acknowledge that -- from my point of view at least -- a majority of this Court has
previously sanctioned the admissibility of an expert opinion pertaining to substantial-
factor causation on terms that would not meet (or even approach) the standards
maintained in these other courts. See Rost v. Ford Motor Co., 637 Pa. 625, 666-76 &
n.6, 151 A.3d 1032, 1057-63 & n.6 (2016) (Saylor, C.J., dissenting) (explaining, inter
alia, that the relevant expert “made no attempt to even roughly quantify either the dose
experienced by [the decedent at his place of employment] or his cumulative exposure or
dose.”). That decision, however, arose in the discrete setting of an asbestos-
mesothelioma case, and it remains to be seen whether, or to what extent, the position
will be transported beyond that unique arena.

3 In terms of Dr. Brautbar’s approach to the scientific studies, epidemiologist David H.
Garabrant, M.D., testified that “scientists have an obligation to consider all relevant
evidence and to weigh it.” Deposition of David H. Garabrant, M.D., dated Jan. 7, 2016,
at 42. Consistent with Judge Wettick’s assessment, Dr. Garabrant explained that Dr.
Brautbar neglected to do so and further failed to apply the Bradford Hill viewpoints
(continued…)
                         [J-92A-E-2019][M.O. – Donohue, J.] - 8
      The circularity inherent in Dr. Brautbar’s opinions is demonstrated throughout his

deposition testimony.    For example, after repeatedly asserting that the amount of

exposure to each of the defendants’ products was substantial, the following interchange

ensued between counsel for an appellant and Dr. Brautbar:

             Q. [I]n terms of duration and the proximity and frequency,
                you don’t know how much of the chemical -- the
                pesticide he was exposed to for the duration or for how
                close he was to it or how frequently?

             A. No. I don’t know.

                           *             *             *

             Q. How -- how much [chlorothalonil] was Mr. Walsh
                exposed to during his work -- during his occupation?

             A. He was exposed to a substantial dose, sufficient to
                contribute to his genotoxicity.

                           *             *             *

             Q. But you can’t tell me how much besides saying
                substantial?

             A. Well, substantial is how much. And it is based on the
                duration, proximity, and frequency.


(…continued)
which he invoked in a reliable manner. See id. at 101. Rather, Dr. Garabrant testified
that Dr. Brautbar “cherry pick[ed].” Id. at 127. In particular, Dr. Brautbar “never
mentions the absence of dose-response relationship in the studies that have examined
it for the pesticides at issue. And so his claim that the dose-response data tends to
support a causal relationship is not true for the pesticides at issue in this case and for
leukemia.” Id. at 131; see also id. at 134 (asserting that Dr. Brautbar “misinterpreted a
number of the [Bradford Hill viewpoints], he’s failed to support others, and he has
invoked chemicals not at issue in this case and diseases not at issue in this case in
support of his views”). Judge Wettick’s close review of some of the studies involved
parallels this line of criticism.


                        [J-92A-E-2019][M.O. – Donohue, J.] - 9
              Q. But you don’t know the dose.

              A. That’s a dose.

                            *             *              *

              Q. Don’t you have to know the amount of the chemical for
                 the duration and the proximity and the frequency to
                 calculate the dose for an individual?

              A. Are you asking me general, or are you asking --

              Q. I’ll ask -- chlorothalonil specifically.    For any of the
                 pesticides involved in this case.

              A. No.

              Q. No? You don’t need to know the amount?

              A. Well, the amount was substantial based on what I have
                 described.
300-303.4

       The record is replete with this sort of exchange, which is along the lines of what

courts have denominated as unscientific ipse dixit (or assertions which are made but not

proven). Cf. Gen. Elec. Co. v. Joiner, 522 U.S. 136, 146, 118 S. Ct. 512, 519 (1997)

(“[N]othing in . . . the Federal Rules of Evidence requires a district court to admit opinion

evidence that is connected to existing data only by the ipse dixit of the expert.”).

4 Although he repeatedly denied it, much of the purport of Dr. Brautbar’s testimony was
that, because he found there to have been an effect on Mr. Walsh’s chromosomes that
in his judgment could only be attributed to benzene or pesticides, Mr. Walsh must have
experienced a sufficient dose from the defendants’ pesticides to have caused it. See,
e.g., N.B. at 511-512. As Appellants explain at length, this represents another example
of circularity in Dr. Brautbaur’s reasoning. See, e.g., Joint Brief for Appellants Bayer
Cropscience LP, Bayer Corp., Bayer Cropscience Holding Inc. & Dow Agrosciences
LLC at 28.



                        [J-92A-E-2019][M.O. – Donohue, J.] - 10
Ultimately, Dr. Brautbar resorted to faulting the appellant companies for the lack of data

underlying his opinions concerning substantial-factor causation. See, e.g., N.B. at 900

(reflecting Dr. Brautbar’s response to an appellant’s attorney that, an “[e]xposure model

can be made if I’m provided with some data from all of you of air monitoring, which

wasn’t provided. So I’m going to throw this back to you.”). There is, of course, no

suggestion on this record that this sort of burden-shifting rationale reflects a generally

accepted scientific methodology.5

       The majority’s holding appears to be that a trial judge must hew more closely to

crediting or discrediting the competing expert testimony about what any particular study

or studies say, rather than actually looking at the studies themselves in the Frye

context. See, e.g., Majority Opinion, slip op. at 25-26, 32. Respectfully, I believe this

imposes an unreasonable constraint on the trial courts’ ability to perform the essential

review for reliability. In this regard, I fail to see how judges can be expected to test

competing opinions from experts while being constrained in their ability to review the

opinions’ underpinnings. Accord Walsh v. BASF Corp., 191 A.3d 838, 849-50 (Pa.


5  There is also ample evidentiary support for Judge Wettick’s rejection of Dr. Brautbar’s
“fingerprints” theory, as lacking any grounding in appropriate scientific methodology.
For example, and as the majority recognizes, a defense expert testified, consistent with
Judge Wettick’s opinion, that this theory is wholly unsupported by the scientific
literature. See Deposition of Marshall Lichtman, M.D., dated December 18, 2015, at 33-
34 (“I did not see any accepted methodology and I could not find any support for the
statement in the material that Dr. Brautbar used to arrive at his opinions.”); id. at 35; id.
at 45 (explaining that “there is [scientific] agreement that there is no cytogenetic pattern
that can allow you to determine if a patient was exposed to a chemical that might have
played a role in causing their case of acute myelogenous leukemia” (emphasis added));
id. at 49-50 (“That’s a novel concept and, as far as I can tell, it’s pulled out of the air.”);
id. at 76; accord Deposition of Michael I. Greenberg, M.D., dated Jan. 15, 2016, at 42-
43 (reiterating that there is no support in the published literature for Dr. Brautbar’s
“fingerprints” opinion).



                         [J-92A-E-2019][M.O. – Donohue, J.] - 11
Super. 2018) (Bender, P.J.E., dissenting). And, upon such consideration, where the

judge discerns a lack of appropriate scientific methodology, I cannot agree that it is

inappropriate for him to so hold.

       I also agree with Judge Wettick and Appellants that both of Appellee’s experts

inappropriately extrapolated from “pesticides” as a product class -- including numerous

pesticides that Mr. Walsh never used -- to Appellees’ specific products, with no analysis

of whether the products were chemically, functionally, or toxicologically similar. Accord

McClain, 401 F.3d at 1245-46 (explaining that ignoring differences in chemical structure

“does not make for reliable opinions in toxic tort cases”). There is also abundant record

evidence confirming that this form of extrapolation lacks general acceptance in the

scientific community. See, e.g., Deposition of David H. Garabrant, M.D., dated Jan. 7,

2016, at 36-37 (analogizing Dr. Zambelli-Weiner’s opinion to the rendering of a

homogenous opinion with respect to the toxic effects of such diverse substances as “a

shot of bourbon, purified water, sugar-sweetened beverages like soda, beer,” simply

because all are beverages).6

6As reflected above, I respectfully disagree with the majority’s pronouncement that Dr.
Brautbar’s analysis was free from extrapolation in relevant regards. See Majority
Opinion, slip op. at 29. Indeed, it is very difficult to understand Dr. Brautbar’s testimony
as anything else besides extrapolation from a class to particular products when he had
no idea of the dose-response threshold associated with any specific product, see e.g.,
N.B. at 798, nor any appreciation of the dose experienced by Mr. Walsh for any product,
see, e.g., id. at 300-301, 552, 798.

Dr. Zambelli-Weiner also extrapolated severely, since her opinion that pesticides as a
class cause leukemia, see, e.g., Deposition of April Zambelli-Weiner, Ph.D., dated Sept.
23, 2014, at 74, can only be understood to apply to Appellees’ discrete products since
they are pesticides, accord id. at 105 (reflecting Dr. Zambelli-Weiner’s explanation that
her opinions “are related to pesticides as a class” and “to the extent that a product is a
pesticide, it is included in that opinion”). And I agree with Judge Wettick that such a
gross form of extrapolation lacks any basis in accepted scientific methodology. See
Walsh, No. GD-10-018588, slip op. at 19 (C.P. Allegheny Oct. 16, 2016).


                        [J-92A-E-2019][M.O. – Donohue, J.] - 12
      With regard to Dr. Zambelli-Weiner specifically, I find Judge Wettick’s

assessment to be compelling that:

             Dr. Zambelli-Weiner’s opinion regarding pesticides as a
             class is not in accordance with generally accepted scientific
             methodology because it fails to account for variations in
             composition of the universe of chemicals, compounds, or the
             like that might be considered a “pesticide.” I find that failure
             to account for such an important variable is not in
             accordance with generally accepted scientific methodology.
Walsh v. BASF Corp., No. GD-10-018588, slip op. at 19 (footnote omitted); accord Joint

Brief for Appellants Bayer Cropscience LP, Bayer Corp., Bayer Cropscience Holding

Inc. & Dow Agrosciences LLC at 35 (“There was no evidence, including from Plaintiff’s

experts, that, for example, citing studies about completely different products to support

a causation opinion is conventional.”); see also id. at 43 (remarking that the class of

pesticides encompasses such substances as cayenne pepper, chlordane, canola oil,

baking soda, and wood preservatives). As Judge Wettick aptly observed, Dr. Zambelli-

Weiner herself recognized that “[p]esticides represent a heterogenous[, or diverse,]

group of formulated products that contain active ingredients and additives.” Walsh v.

BASF Corp., No. GD-10-018588, slip op. at 19 n.17 (citing Deposition of April Zambelli-

Weiner, Ph.D., dated September 23, 2014, at 104-107) (emphasis in original).

      In other cases, and along with other Justices, I have recognized the difficulties

facing plaintiffs in toxic tort cases involving exposure to multiple products and long

latency periods. See, e.g., Gregg v. V-J Auto Parts, Inc., 596 Pa. 274, 291-92, 943

A.2d 216, 226 (2007). Again, I would permit a fair degree of latitude, for example in

terms of estimating exposure and dose. See, e.g., Rost, 637 Pa. at 676 n.13, 151 A.3d

at 1063 n.13 (Saylor, C.J., dissenting).     However, the proffer -- before a jury of

laypersons --- of expert witnesses whose methodologies are replete with ungrounded

extrapolations and other analytical gaps, large-scale abstractions, and patent circularity

                       [J-92A-E-2019][M.O. – Donohue, J.] - 13
goes far beyond any reasonable conception of appropriate leeway. Accord Accutane,

191 A.3d at 589 (emphasizing that the court’s function on review of novel scientific

opinions “is to distinguish scientifically sound reasoning from that of the self-validating

expert, who uses scientific terminology to present unsubstantiated personal beliefs”).

      For the above reasons, I would reverse the order of the Superior Court.


             II. Response to the Concurring Opinion by Justice Wecht

      According to Justice Wecht, the opinion that I authored in Betz suffers from a

“reliance upon potentially misleading terminology” and “so muddied the waters that this

Court should stabilize its characterization of the Frye standard[.]” Concurring Opinion,

slip op. at 5. In this regard, he intimates that Betz “introduced into Pennsylvania law a

‘conventionality’ requirement, suggesting that expert testimony in a scientific discipline

is admissible only when the expert has ‘applied accepted scientific methodology in a

conventional fashion in reaching his or her conclusions.’” Id. at 14 (emphasis in original;

citation omitted). Justice Wecht further cites, inter alia, to Commonwealth v. Jacoby,

642 Pa. 623, 170 A.3d 1065 (2017), as a decision evidencing the same deficiency

which he attributes to Betz. See Concurring Opinion, slip op. at 14 & n.10.

      As an initial matter, Justice Wecht’s opinion demonstrates a misunderstanding of

the Betz decision, in that the “conventional fashion” language simply wasn’t used to

redefine Frye’s general-acceptance standard.      Rather, the phrase appears, in Betz,

solely in a section entitled, “The Decision to Conduct a Frye Hearing.” Consistent with

this heading, the passage discusses only the concept of the novelty of scientific

evidence, which serves as the threshold to the entitlement to a Frye hearing. See Betz,

615 Pa. at 544-46, 44 A.3d at 52-53 (“We conclude that a Frye hearing is warranted

when a trial judge has articulable grounds to believe that an expert witness has not



                        [J-92A-E-2019][M.O. – Donohue, J.] - 14
applied accepted scientific methodology in a conventional fashion in reaching his or her

conclusions.” (emphasis added)).

         Notably, this is the same limited context in which conventionality was considered

in the Jacoby decision referenced by Justice Wecht. See Jacoby, 642 Pa. at 667, 170

A.3d at 1091. Indeed, the novelty threshold was the only tier of a Frye analysis that the

Jacoby Court was able to review, given that the trial court had denied the defendant’s

motion for a Frye hearing, and accordingly, no application of the Frye general-

acceptance test whatsoever had occurred in the case. See id. at 640, 170 A.3d at

1075.7

         Viewing the contested phraseology in its appropriate setting, I do not find it to be

confusing, at all, to say that scientific methodology applied in an unconventional fashion

fairly translates into novel scientific evidence (particularly since novelty and

unconventionality are often used as synonyms).               And the Court’s unanimous

determination on this subject, in Betz, didn’t stray off course. Instead, the question of


7 The “conventional fashion” language taken from Betz was also used in this manner in
each of the remaining decisions and responsive opinions in this Court cited by the
concurrence. See Mitchell v. Shikora, ___ Pa. ___, ___ n.12, 209 A.3d 307, 319 n.12
(2019); Commonwealth v. Walker, 625 Pa. 450, 489, 92 A.3d 766, 790 (2014);
Commonwealth v. Treiber, 632 Pa. 449, 538, 121 A.3d 435, 488 (2015) (Saylor, C.J.,
dissenting).

Parenthetically, the majority opinion in Jacoby does manifest an idiosyncrasy in its own
right, since it characterizes unconventionality in methodology as the exclusive measure
for novelty. See Jacoby, 642 Pa. at 667, 170 A.3d at 1091. On the novelty issue,
however, Betz only decided the issue that was before the Court -- i.e., whether the
concept of novelty subsumed generally-accepted methodology applied in an
unconventional fashion. There should never have been any doubt that Frye also
extends to “novel science” -- for example, a new scientific test for truth-telling -- in the
first instance. See Betz, 615 Pa. at 545, 44 A.3d at 53 (citing Grady, 576 Pa. at 557,
839 A.2d at 1045).



                          [J-92A-E-2019][M.O. – Donohue, J.] - 15
whether the concept of novelty extended to novel (or unconventional) applications of

otherwise-accepted scientific methodology was squarely presented by the litigants as a

main, contested issue in the case.8          Furthermore, contrary to Justice Wecht’s

characterization, the matter was decided on amply-developed reasoning.9


8 In this regard, the issue was raised and developed -- and discussed extensively -- by
the parties and their amici. Compare Betz, 615 Pa. at 530-31, 44 A.3d at 43-44
(reflecting that the defendant-appellants contended that a Frye hearing was warranted
because, while the challenged expert “ostensibly accepted the applicability of”
conventional scientific methodology, his opinion “in substance, nevertheless disregards
this elemental precept in its entirety”), with id. at 542-43, 44 A.3d at 51 (summarizing the
plaintiff-appellees’ argument that there was “no justification for conducting a Frye
hearing,” since their expert’s methodology was “utterly mainstream”).

9 Betz relates that Pennsylvania courts tend to downplay access to other rule-based
tools for trial judges to screen scientific evidence, such as the ability to refuse to admit
evidence to avoid unfair prejudice, confusion of the issues, or misleading the jury. See
Betz, 615 Pa. at 544, 44 A.3d at 52 (citing Pa.R.E. 403, as well as the helpfulness
consideration of Rule of Evidence 702). This, of course, tends to elevate the
importance of appropriate screening under Frye. Additionally, the Court reasoned as
follows:

              Various reasons underlie the preference to limit the courts'
              involvement in determining the admissibility of scientific
              evidence. There is the concern that liberality in allowing
              challenges would substantially increase the number of
              challenges (and cases in which lengthy pre-trial proceedings
              would ensue). The competency of trial judges to accept or
              reject scientific theories remains a legitimate subject of
              controversy. Additionally, a claim or defense in many cases
              may rise or fall based upon expert testimony and, therefore,
              there is some reluctance on the part of courts to deprive
              litigants of their day in court.

            On the other hand, this Court has recognized the influential
            nature of expert testimony on complex subjects, and the
            potential that distortions have to mislead laypersons. See
            [Grady, 576 Pa.] at 558, 839 A.2d at 1045; Topa, 471 Pa. at
            231–33, 369 A.2d at 1281–82. It would be naïve, in this
(continued…)
                        [J-92A-E-2019][M.O. – Donohue, J.] - 16
      In any event, the digression about passages from Betz dedicated to novelty

seems to me to be of little relevance to this case, since the claim that prevailed before

Judge Wettick was that Dr. Brautbar’s methodology was not only unconventional, but it

was wholly unscientific.10 One of the pillars of the Betz opinion is that trial judges are

authorized -- and obliged upon proper challenge -- to screen against expert witnesses

who profess to apply accepted scientific methodology but instead, present analyses

suffering from material analytical gaps. See Betz, 615 Pa. at 553, 44 A.3d at 57-58.


(…continued)
            regard, to assume that the possibility for distortion is limited
            to the very newest realms of science. Cf. Grady, 576 Pa. at
            557, 839 A.2d at 1045 (explaining that Frye applies not only
            to novel science, but also where scientific methods are
            utilized in a novel way).

             We therefore agree with Appellants that a reasonably broad
             meaning should be ascribed to the term “novel.”

Betz, 615 Pa. at 545, 44 A.3d at 53.

10 In this regard, since unscientific methodology is also unconventional, there is a great
deal of overlap between the terms. And I would submit that the greater range of cases
in which scientific evidence is excluded, as this one, address evidence that is both
unconventional and unscientific. See supra note 2.

Certainly, the substantive Frye test shouldn’t be applied so stringently as to absolutely
forbid scientific methodology applied in a unique way, so long as the new manner itself
can reasonably be viewed as scientific (or as being sufficiently grounded in generally-
accepted principles). This is why the Betz Court chose the “unconventional” litmus
solely to identify situations where the courts should take a close look (i.e., conduct a
Frye hearing) to screen against unscientific lapses in the methodology, such as
analytical gaps and abstractions.

As related above and below, the particular strain of “unconventionality” embedded in Dr.
Brautbar’s opinions -- i.e. material analytical gaps and abstractions -- is and should be
excluded from courtrooms. See infra.



                       [J-92A-E-2019][M.O. – Donohue, J.] - 17
The alternative to permitting trial courts to consider whether experts actually adhere to

the methodology that they only facially espouse is to accept the sort of expert self-

validation which is of great concern to most courts.11

      One need look no further than the FBI’s recent revelation that, for decades, the

government engendered the presentation of faulty forensic-science evidence -- in the

form of microscopic hair analysis -- potentially impacting tens of thousands of criminal

cases across the nation. See FBI Press Release, FBI Testimony on Microscopic Hair

Analysis Contained Errors in at Least 90 Percent of Cases in Ongoing Review, at 2

11
 As a separate matter, during the course of his critique of Betz, without citation, Justice
Wecht restates the holding as follows:

             In Betz, . . . the Court appeared to hold, and unquestionably
             implied, that when an expert testifies that any exposure to a
             toxic substance enhances the risk that the exposed party will
             suffer injury as a consequence of that particular exposure,
             the expert inadmissibly suggests that the exposure in
             question, even when de minimis, is a substantial cause of
             the injury.

Concurring Opinion, slip op. at 20. In Betz, however, there simply was no reason for the
Court to infer anything about substantial-factor causation from discussions by the
challenged expert about increased risk in the abstract. Rather, the case concerned the
challenged expert’s explicit opinion that was offered as the sole evidence to address the
plaintiff-appellees’ burden to prove substantial-factor causation. In this regard, the
specific opinion at issue was that de minimus exposure -- i.e., breathing a single
asbestos fiber from a defendant’s product -- was a substantial factor in causing any
given instance of asbestos-related disease in any individual who was so exposed. See
Betz, 615 Pa. at 510, 44 A.3d at 31.

Along these lines, I find the concurrence’s assertion that Rost appropriately overruled
the above rationale attributed to Betz to be equally misplaced. See Concurring Opinion,
slip op. at 20-21.

I have acknowledged nonetheless, that the majority decision in Rost did work a distinct
retrenchment relative to Betz, at least insofar as concerns asbestos-mesothelioma
cases. See supra note 2.


                        [J-92A-E-2019][M.O. – Donohue, J.] - 18
(Apr. 2, 2015). Of course, the misuse of science in courtrooms tends to impugn the

integrity of the judicial system. See, e.g., Commonwealth v. Chmiel, 643 Pa. 216, 225,

173 A.3d 617, 622 (2017) (referencing a Washington Post article charging that the FBI’s

review was “a watershed in one of the country’s largest forensic scandals, highlighting

the failure of the nation’s courts for decades to keep bogus scientific information from

juries” (emphasis added)). See generally Edward J. Imwinkelreid, The Best Insurance

Against Miscarriages of Justice Caused By Junk Science: An Admissibility Test That Is

Scientifically and Legally Sound, 81 ALB. L. REV. 851, 851 (2018) (“Inaccurate expert

testimony is a ‘recurrent theme[]’ in wrongful conviction studies.”).

       Accordingly, courts that look beyond mere acceptance of an expert’s own

personal claim to adherence to an accepted scientific methodology quite appropriately

seek to protect the integrity of the judicial process.

       Notably, other jurisdictions adhering to Frye’s general-acceptance litmus have

approved judicial screening against the admission of faulty expert analyses in a fashion

very similar to that required under Betz. See, e.g., Goeb v. Tharaldson, 615 N.W.2d

800, 816 (Minn. 2000) (applying a Frye analysis to require a proponent of scientific

evidence to show that the “methodology used [by the expert] is reliable and in the

particular instance produced reliable results,” and affirming the exclusion of testimony

from an expert whose analysis made “too great a leap” from the data gathered

(emphasis added)). See generally Blackwell v. Wyeth, 971 A.2d 235, 254 (Md. 2009)

(“The ‘analytical gap’ concept also has been employed by some of our sister states in a

Frye analysis.” (citing, inter alia, the Minnesota Supreme Court’s decision in Goeb)).12


12 Maryland maintains a variant of the Frye test which distinguishes between generally
accepted methodology and generally accepted analysis, while clarifying that both are
required “to avoid the pitfalls of an ‘analytical gap.’” Blackwell, 971 A.2d at 255. In my
view, it is largely a semantic issue whether an expert who professes to have applied a
(continued…)
                         [J-92A-E-2019][M.O. – Donohue, J.] - 19
       Nor was Betz’s review of a scientist’s actual methodology a novelty in

Pennsylvania. In Blum v. Merrell Dow Pharmaceuticals, Inc., the challenged expert

testified at a Frye hearing that his opinions “were based on generally accepted

methods.” Blum by Blum v. Merrell Dow Pharmaceuticals, Inc., 705 A.2d 1314, 1321

(Pa. Super. 1997), aff’d, 564 Pa. 3, 764 A.2d 1 (2000). Nevertheless, the Superior

Court concluded that such self-validating testimony was “not enough” to carry the

proponent’s burden at a Frye hearing. Id. Significantly, in affirming this conclusion, this

Court reviewed the record and explained that the expert “engaged in a selective review

of the data from several” studies; “detached the underlying data from the controls set up

by the studies”; and “worked backwards through the science, from the statistical results

back to the studies in the first place.” Blum, 564 Pa. at 7 n.5, 764 A.2d at 4 n.5. As

such, and as in Betz, the Court concluded that “[t]his procedure cannot be fairly

described as generally accepted methodology for purposes of the Frye standard.” Id.

       As I have previously explained, I don’t believe the present case presents an

appropriate vehicle for engaging in a merits defense of either the Frye or Daubert

criteria or any other existing or proposed standard, since there is no present advocacy

on the subject. I observe, however, that some of the authorities that Justice Wecht

(…continued)
generally accepted scientific methodology -- but who has in fact failed to do so -- hasn’t
applied that methodology as a factual matter, or has been deficient in his applied
reasoning. Under either understanding, the expert’s unscientific and misleading
testimony presents precisely the same danger associated with its misuse in a
courtroom.

In this regard, a constant and contested theme, in this line of cases, is that one party’s
expert will say that he or she followed generally-accepted scientific methodology, and
the adversary’s expert will say this is not so. There would be no reason for a Frye
hearing if a neutral judicial official were not interposed to resolve such a material factual
dispute.



                        [J-92A-E-2019][M.O. – Donohue, J.] - 20
discusses in his defense of Frye depart greatly from his central thesis. For example, the

concurrence references an article by law fellow and Ph.D. candidate James R. Dillon to

support the propositions that judges lack the expertise to address scientific evidence in

the courtroom, and that Frye more appropriately delegates the question of the reliability

of the actual methodology or reasoning employed to experts selected by the litigants.

See Concurring Opinion at 19 (citing James R. Dillon, Expertise on Trial, 19 COLUM. SCI.

& TECH. L. REV. 247, 260, 272 (2018)).

       Relative to the comment about judicial expertise, however, the article also

espouses the view that jurors lack the necessary competence to assess the reliability of

scientific evidence. See, e.g., Dillon, Expertise on Trial, 19 COLUM. SCI. & TECH. L. REV.

at 278 (opining that “[j]urors often fail to understand and apply scientific testimony

correctly, even when the underlying science itself is relatively clear,” and that jurors tend

to rely on “cognitive shortcuts,” such as a focus upon “perceived expertise”). Moreover,

the theme runs throughout the Dillon article that judges must implement an effective

gatekeeping function to keep faulty science out of courtrooms, at the risk of

compromising the integrity of the judicial system. In this regard, the author departs

roundly from Justice Wecht’s position concerning the effectiveness of traditional

adversarial tools of common-law adjudication, including cross-examination, the

introduction of competing evidence, and argumentation by counsel.                         Compare

Concurring Opinion, slip op. at 8, with Dillon, Expertise on Trial, 19 COLUM. SCI. & TECH.

L. REV. at 280 (“The empirical literature also casts doubt on the effectiveness of the

traditional tools of the adversarial model . . . in mitigating jurors’ cognitive fallibilities.”).

       The author further submits that the Frye approach, devised in 1923, had failed to

counteract a “sporting theory” associated with the use of partisan expert witnesses in

courtrooms, which was appalling to the public and produced a crisis of confidence in the


                          [J-92A-E-2019][M.O. – Donohue, J.] - 21
judicial system, at least until courts began to “apply Frye more stringently in the 1970s.”

Id. at 259. Ultimately, the author proposes the appointment of a “scientific adjunct with

expertise in each relevant scientific domain,” in every civil and criminal case, who would

have the authority to engage in sua sponte gatekeeping; to conduct and implement

independent research and analyses, respectively; and to overturn jury verdicts which

the adjunct finds to be contrary to scientific fact. Id. at 297-300.

       Plainly, this article does not comport with Justice Wecht’s position that

Pennsylvania should remain “a Frye stalwart” with no further consideration of any other

alternative. Compare Concurring Opinion, slip op. at 13, with Dillon, Expertise on Trial,

19 COLUM. SCI. & TECH. L. REV. at 312 (“Maintaining the status quo is not a viable

option.”).

       Personally, at this point in time, I wouldn’t endorse the Dillon article any more

than I would subscribe to Justice Wecht’s sua sponte defense of Frye.13 Instead, I

reiterate my belief that very serious and difficult questions remain that would be better

addressed by this Court upon developed argumentation and with due consideration of

the many concerns arising out of the ongoing experience with the misuse of faulty

science in courtrooms.14

13I note that there are other proposals for improvement that may also merit serious
consideration. See, e.g., Imwinkelreid, The Best Insurance Against Miscarriages of
Justice Caused By Junk Science: An Admissibility Test That Is Scientifically and
Legally Sound, 81 ALB. L. REV. at 865-66.

14 Notably, as well, the Betz Court never made a definitive ruling as to whether trial
courts could separately enforce Rule of Evidence 702’s requirement that expert opinion
must assist the trier of fact to understand the evidence or determine a fact in issue, or
Rule 403’s screening requirement against unfair prejudice, confusion of the issues, or
misleading of the jury. See Pa.R.E. 403, 702. From my point of view, close
consideration also should be accorded to empowering trial courts to separately enforce
these material requirements in the expert-testimony arena. But see Majority Opinion,
slip op. at 21 n.7 (“To the extent that Pennsylvania trial courts conduct an ‘essential
(continued…)
                         [J-92A-E-2019][M.O. – Donohue, J.] - 22
       Justice Todd joins this dissenting opinion.




(…continued)
review for reliability,’ that review may consist only of establishing that the expert utilized
generally accepted methodologies in reaching his or her scientific conclusions.” (internal
citation omitted)).


                        [J-92A-E-2019][M.O. – Donohue, J.] - 23
