                                       PRECEDENTIAL

       UNITED STATES COURT OF APPEALS
            FOR THE THIRD CIRCUIT
                ______________

                 Nos. 18-3126, 18-3127
                   ______________

                 UGI SUNBURY LLC,
                          Appellant

                           v.

A PERMANENT EASEMENT FOR 1.7575 ACRES, AND
    TEMPORARY CONSTRUCTION AND ACCESS
    EASEMENT FOR 2.956 ACRES IN LIMESTONE
 TOWNSHIP, MONTOUR COUNTY, PENNSYLVANIA
 TAX PARCEL NO. 5-10-19; DAVID W. BEACHEL, JR.;
  JOY L. BEACHEL; THE TURBOTVILLE NATIONAL
 BANK; MONTOUR COUNTY TAX CLAIM BUREAU;
COMMONWEALTH OF PENNSYLVANIA, Department of
      Highways, PA Department of Transportation;
PENNSYLVANIA DEPARTMENT OF REVENUE, Bureau
      of Compliance; ALL UNKNOWN OWNERS
                  ______________

     On Appeal from the United States District Court
         for the Middle District of Pennsylvania
                 (D.C. No. 3:16-cv-00788)
      District Judge: Honorable Matthew W. Brann
                     ______________
                   UGI SUNBURY LLC,
                              Appellant

                              v.

A PERMANENT EASEMENT FOR 0.4308 ACRES, AND
    TEMPORARY CONSTRUCTION AND ACCESS
EASEMENT FOR 0.4577 ACRES IN THE BOROUGH OF
         SHAMOKIN DAM, SNYDER COUNTY,
    PENNSYLVANIA TAX PARCEL NO 16-04-059;
DONALD D. PONTIUS, Co-Trustees of the Donald D. and
 Georgia A. Pontius Living Trust; GEORGIA A. PONTIUS,
Co-Trustees of the Donald D. and Georgia A. Pontius Living
        Trust; BOROUGH OF SHAMOKIN DAM;
COMMONWEALTH OF PENNSYLVANIA, Department of
       Transportation; ALL UNKNOWN OWNERS
                     ______________

      On Appeal from the United States District Court
          for the Middle District of Pennsylvania
                  (D.C. No. 3:16-cv-00794)
       District Judge: Honorable Matthew W. Brann
                      ______________

                 Argued September 19, 2019

      Before: KRAUSE, MATEY, Circuit Judges, and
       QUIÑONES ALEJANDRO, District Judge.


       
        Honorable Nitza I. Quiñones Alejandro, District
Judge, United States District Court for the Eastern District of
Pennsylvania, sitting by designation.




                              2
            (Opinion Filed: February 11, 2020)

Paige Macdonald-Matthes
Obermayer Rebmann Maxwell & Hippel
200 Locust Street, Suite 400
Harrisburg, Pennsylvania 17101

Alexander V. Batoff
Obermayer Rebmann Maxwell & Hippel
1500 Market Street Center Square West, 34th Floor
Philadelphia, Pennsylvania 19102

James C. Martin            (Argued)
Devin M. Misour
Reed Smith LLP
225 Fifth Avenue
Pittsburgh, Pennsylvania 15222
       Counsel for Appellant UGI Sunbury, LLC

Peter J. Carfly
Stephen B. Edwards         (Argued)
Laverly Law
225 Market Street, Suite 304
P.O. Box 1245
Harrisburg, Pennsylvania 17108
       Counsel for Appellees David W. Beachel, Jr.,
       Permanent Easement For 1.7575 Acres and Temporary
       Construction and Access Easement for 2.956 Acres in
       Limestone Township Montour County Pennsylvania
       Tax Parcel No. 5-10-19, and Joy L. Beachel

Michael F. Faherty        (Argued)
Anthony M. Corby




                            3
Tara B. Hovarth
Faherty Law Firm
75 Cedar Avenue
Hershey, Pennsylvania 17033
      Counsel for Appellees Donald D. and Georgia A.
      Pontius, Trustees of the Donald D. and Georgia A.
      Pontius Living Trust

Stephanie E. DiVittore
Barley Snyder
213 Market Street
12th Floor
Harrisburg, Pennsylvania 17101
       Counsel for Turbotville National Bank

Brian J. Clark
Buchanan Ingersoll & Rooney
409 North Second Street, Suite 500
Harrisburg, Pennsylvania 17101

Victoria B. Kush
Stanley Yorsz
Buchanan Ingersoll & Rooney
301 Grant Street
One Oxford Centre, 20th Floor
Pittsburgh, Pennsylvania 15219
       Counsel for Amicus Curiae Marcellus Shale Coalition

Lela Hollabaugh
Bradley Arant Boult Cummings
1600 Division Street, Suite 700
Nashville, Tennessee 37203




                             4
Anna M. Manasco
Bradley Arant Boult Cummings
1819 Fifth Avenue North
One Federal Place
Birmingham, Alabama 35203
      Counsel for Amicus Curiae Interstate Natural Gas
Association of America

Robert H. Thomas
Damon Key Leong Kupchak Hastert
1003 Bishop Street, Suite 1600
Honolulu, Hawaii 96813
      Counsel for Amicus Curiae Owners Counsel of America
                     ______________

                         OPINION
                      ______________

MATEY, Circuit Judge.

       “An intelligent evaluation of facts is often difficult or
impossible without the application of some scientific,
technical, or other specialized knowledge.” Fed. R. Evid. 702
advisory committee’s note to 1972 proposed rules. But not all
specialized knowledge can claim the label of reliable science.
So trial courts must guard against “expertise that is fausse and
science that is junky.” Kumho Tire Co. v. Carmichael, 526 U.S.
137, 159 (1999) (Scalia, J., concurring). And for more than
twenty-five years, federal courts have looked to the familiar
framework of Federal Rule of Evidence 702 to fulfill their
“responsibility of acting as gatekeepers to exclude unreliable
expert testimony.” Fed. R. Evid. 702 advisory committee’s
note to 2000 amendments.




                               5
        Despite the complex factual and procedural setting of
this consolidated appeal, this matter turns on a simple question:
what is the standard for the admissibility of expert testimony
in a condemnation proceeding under the Natural Gas Act? Rule
702 supplies the answer and requires reliable expert testimony
that fits the proceedings. That standard recognizes that “[t]he
more tightly law is bound to good science, the more orderly
and predictable the legal process will become.” Peter W.
Huber, Galileo’s Revenge: Junk Science in the Courtroom 215
(1991). By contrast, the expert testimony presented here is
bound only to speculation and conjecture, not good science or
other “good grounds.” Karlo v. Pittsburgh Glass Works, LLC,
849 F.3d 61, 81 (3d Cir. 2017) (quoting In re TMI Litig., 193
F.3d 613, 665 (3d Cir. 1999)). So we will vacate the District
Court’s judgments and remand these cases for new valuation
proceedings.

                       I. BACKGROUND

A.     UGI Obtains Easements to Build a Natural Gas
       Pipeline

      UGI Sunbury, LLC builds natural gas pipelines. In
accordance with the Natural Gas Act, 15 U.S.C. §§ 717 et seq.,
it obtained authorization to construct and operate an
underground pipeline along a 34.4-mile stretch of land in
Pennsylvania. The pipeline crosses underneath properties
owned by David W. Beachel, Jr. and Donald D. and Georgia
A. Pontius.1 The Landowners rejected UGI’s offers of


       1
       The Beachel property is a dairy and poultry farm
encompassing 96.2988 acres in Limestone Township,




                               6
compensation for rights of way, so UGI filed complaints
seeking orders of condemnation. UGI prevailed, winning
temporary and permanent easements over the Landowners’
properties to construct the pipeline.2

B.     Determining Just Compensation

       With the easements awarded, only the amount of
compensation remained. To aid the District Court’s
calculation, UGI and the Landowners retained valuation
experts. The Landowners both offered Don Paul Shearer who
produced reports on the effect of the easements.3 Shearer

Pennsylvania and includes a single-family home, a barn, and
several agricultural outbuildings. The Pontius property is a
commercial strip covering 1.6050 acres in Shamokin Dam,
Pennsylvania and includes two buildings. Donald D. and
Georgia A. Pontius are trustees of the Donald D. and Georgia
A. Pontius Living Trust. We refer to owners of both the
Beachel and Pontius properties as “the Landowners.”
       2
         In the Beachel matter, the District Court awarded UGI
a permanent easement of 1.7575 acres and a temporary
easement of 2.9560 acres. In the Pontius matter, the District
Court awarded UGI a permanent easement of 18,766 square
feet and a temporary easement of 19,937 square feet. UGI
challenges neither award in this appeal.
       3
         Shearer has testified frequently in valuation disputes.
Frequent too are decisions critical of his findings. O’Neal v.
Dep’t of the Army, 852 F. Supp. 327, 334 (M.D. Pa. 1994)
(describing Shearer’s testimony as “conjecture”); In re
McElwee, 449 B.R. 669, 675–76 (Bankr. M.D. Pa. 2011)
(ascribing “less weight” to Shearer’s valuation because of “the
relative weakness” of the data “he considered in arriving at his




                               7
estimated the before-taking value of the land by comparing
properties in the area and opining on what each is worth
relative to the market. UGI does not challenge this approach.

       As for the post-taking property values, Shearer’s reports
rely on his own “damaged goods theory,” drawing on his
experience working in his grandfather’s appliance shop.
Shearer rounded out this model by studying the impact on real
estate values from the Three Mile Island nuclear incident in
1979, the Exxon Valdez Alaskan oil spill in 1989, and assorted
leaking underground storage tanks. Not only do Shearer’s
reports contain only passing reference to these studies, they
include no data relating to those incidents. Indeed, he did not
attach his prior studies to his reports.

       As applied, Shearer’s “damaged goods theory” holds
that markets treat real estate near actual, or even perceived
environmental contamination, as a damaged good. Shearer
opined that “based on public perception of natural gas pipelines
that are in close proximity to any real estate, the subject
property does and will continue to have some long-term stigma
on the overall marketability and market value.” (App. at 132;
accord App. at 702.) As a result, it “will be treated as damaged
goods now and in the permanent future.” (App. at 132; accord
App. at 702.) Shearer further offered that “any serious potential
purchaser is going to discount the price(s) offered for the
property based on the stigma and damaged goods aspects of the
property after the taking and existence of the natural gas

opinion of value”); In re DeFacto Condemnation & Taking of
Lands of WBF Assocs., 972 A.2d 576, 586 (Pa. Commw. Ct.
2009) (affirming exclusion of Shearer’s valuation testimony).
UGI has not appealed the District Court’s findings on Shearer’s
qualifications.




                               8
pipeline[.]” (App. at 132; accord 702.) Using this theory,
Shearer concluded that the total compensation for the taking
was $386,000 for the Beachel property (a 40 percent reduction
in value) and $456,000 for the Pontius property (a 60 percent
reduction in value).

C.     The District Court Admits and Relies on Shearer’s
       Testimony

        UGI moved in limine to exclude Shearer’s testimony for
failure to meet the standards required by Rule 702. The District
Court recognized Rule 702’s parameters but noted its “wide
discretion when deciding whether those requirements have
been met.” (App. at 150–51; accord App. at 795.) The District
Court added that “[b]ecause the upcoming trial is a bench—not
jury—trial, because there is a ‘strong preference for admission’
of expert testimony, and because this Court believes that
‘hearing the expert’s testimony and assessing its flaws [is] an
important part of assessing what conclusion [is] correct,’ this
Court will admit the testimony of both parties’ experts.” (App.
at 151 (internal footnotes and citations omitted); accord App.
at 795–96.)

        Shearer’s trial testimony did not expand on his theory
or offer other supporting data. For example, during the Beachel
trial, when asked whether there was “data either way to say that
a pipeline across the property diminishes the property or has
no effect [on] the property,” Shearer responded, “Not yet. I’m
prognosticating.” (App. at 333.) When asked “where in [his]
report is [any] support that the entire property . . . [is] a high
consequence area?,” Shearer stated, “It’s not in my report.”
(App. at 385.) And when pressed to explain how he valued the
depreciation using his “damaged goods theory[,]” Shearer
replied that the pipeline necessarily attaches a stigma so future




                                9
buyers are simply “going to pay less. How much less? Who
knows.” (App. at 332.)

       Likewise, during the Pontius trial, Shearer agreed with
the District Court’s characterization that “there is at least some
leap of logic” necessary to correlate the incident at Three Mile
Island or an ocean oil spill to the UGI easements. (App. at 821.)
Ever candid, Shearer agreed “that there is an element of
subjectivity or even speculation in [his] approach.” (Id.) The
Pontius trial also incorporated testimony Shearer provided at a
previous valuation hearing involving UGI and another
landowner. There he explained his methodology: “I said to
myself five or ten? I thought more than that. Forty? Nah. Nah,
it’s—25? I know this sounds kind of crazy.” (App. at 1040.)

       The District Court found this compelling, stating that it
was “inclined to agree with Mr. Shearer that some form of
‘stigma’ attaches to the property as a whole.” (App. at 19;
accord App. at 34.) Indeed, that qualified, tentative
endorsement of Shearer’s theory was the only factual analysis
supporting the valuation awards. And on that basis, the Court
found the value of the Beachel property was reduced by 15
percent, not the 40 percent recommended by Shearer, and
awarded Beachel $126,932.48 for the permanent easement,
temporary easement, prejudgment interest, and an offset
already paid to a co-owner of the property. The Court’s
reasoning on the Pontius property was virtually identical,
concluding the easements reduced the value by 30 percent,
rather than the 60 percent estimated by Shearer. The District
Court awarded $254,228.39 for the value of the permanent
easement, temporary easement, and prejudgment interest.




                               10
    II. JURISDICTION AND THE STANDARD OF REVIEW

       The District Court had subject matter jurisdiction under
28 U.S.C. § 1331 and under the Natural Gas Act, 15 U.S.C. §
717f(h), authorizing eminent domain actions. We have
jurisdiction under 28 U.S.C. § 1291. We review the
admissibility of expert testimony for an abuse of discretion.
United States v. 68.94 Acres of Land, 918 F.2d 389, 392 (3d
Cir. 1990). It is a narrow standard satisfied “only when the
decision rests upon a clearly erroneous finding of fact, an errant
conclusion of law or an improper application of law to fact.”
Schneider ex rel. Estate of Schneider v. Fried, 320 F.3d 396,
404 (3d Cir. 2003) (internal quotation marks omitted). If we
find abuse, “we review de novo whether that error was
prejudicial or harmless.” United States v. Schneider, 801 F.3d
186, 200 (3d Cir. 2015). In contrast, we review fact finding
during the bench trial for clear error. Nat’l Sec. Sys., Inc. v.
Iola, 700 F.3d 65, 81 (3d Cir. 2012).

 III. THE EXPERT TESTIMONY LACKED RELIABILITY AND
  THE THEORY OF VALUATION FAILED TO FIT THE CASE

        UGI advances two arguments on appeal. The first
hinges on the gatekeeping requirement under Federal Rule of
Evidence 702 and Daubert v. Merrell Dow Pharmaceuticals,
Inc., 509 U.S. 579 (1993). UGI contends that Shearer’s opinion
was not reliable and did not fit the facts of these cases, and so
the District Court abused its discretion in denying UGI’s
motions to exclude his testimony. The second centers on
Federal Rule of Civil Procedure 52, which governs actions
tried on the facts without a jury. UGI argues that the District
Court clearly erred both in relying on Shearer’s unreliable
testimony and in articulating no factual foundation for its
damages findings. The Landowners fight back on both fronts,




                               11
insisting that Shearer’s testimony was not fatally subjective
and that the District Court’s findings were supported by
competent evidence.

A.     Federal Rule of Evidence 702 Applies to Bench
       Trials

        In a pipeline condemnation proceeding, valuing the
condemned property is a first step to calculating the
compensation owed to the landowner. Tenn. Gas Pipeline Co.
v. Permanent Easement for 7.053 Acres, 931 F.3d 237, 243–44
(3d Cir. 2019). And given the technical nature of that question,
expert testimony “acquires special significance in an eminent
domain proceeding where the sole issue is the value of
condemned property.” 68.94 Acres, 918 F.2d at 393. UGI
contends Shearer’s expert testimony did not satisfy Rule 702
because it was not reliable and did not fit the facts of these
cases, so the District Court abused its discretion in denying
UGI’s motions to exclude the testimony. The Landowners
insist that Shearer’s testimony was not fatally subjective and
that the District Court was within its discretion to rely on his
testimony. The answer centers on the gatekeeping obligation
imposed on trial courts under Federal Rule of Evidence 702
and Daubert v. Merrell Dow Pharmaceuticals, Inc., 509 U.S.
579 (1993).

       We start with a clarification about the role Rule 702
plays in bench trials. As we have explained, “a trial judge acts
as a gatekeeper to ensure that any and all expert testimony or
evidence is not only relevant, but also reliable.” Pineda v. Ford
Motor Co., 520 F.3d 237, 243 (3d Cir. 2008) (internal
quotation marks omitted). As gatekeeper, a trial judge has three
duties: (1) confirm the witness is a qualified expert; (2) check
the proposed testimony is reliable and relates to matters




                               12
requiring scientific, technical, or specialized knowledge; and
(3) ensure the expert’s testimony is “sufficiently tied to the
facts of the case,” so that it “fits” the dispute and will assist the
trier of fact. Daubert, 509 U.S. at 591 (quoting United States
v. Dowling, 753 F.2d 1224, 1242 (3d Cir. 1985)). The text of
Rule 702 contains no exception to these requirements, so if
they are not satisfied, an expert cannot testify before the “trier
of fact.” Fed. R. Evid. 702.

         Rule 702 applies whether the trier of fact is a judge or a
jury. By using the term “trier of fact,” rather than specifying
judge or jury, Rule 702 does not distinguish between
proceedings. Contrast that language with Federal Rule of
Evidence 403, permitting a court to “exclude relevant evidence
if its probative value is substantially outweighed by a danger
of . . . misleading the jury.” Fed. R. Evid. 403. Given that Rule
702 was “amended in response to Daubert . . . and to the many
cases applying Daubert, including Kumho Tire,” and its text
continues to employ the broad “trier of fact” instead of the
more specific “jury,” district courts must apply Rule 702 to
assess an expert’s qualifications, reliability, and fit before
weighing the expert’s opinions to decide a triable issue. Fed.
R. Evid. 702 advisory committee’s note to 2000 amendments
(“The trial judge in all cases of proffered expert testimony must
find that it is properly grounded, well-reasoned, and not
speculative before it can be admitted.”); see also Fed. R. Evid.
1101(a) (applying the Federal Rules of Evidence to
proceedings before district courts).

       Of course, district courts do retain “latitude” to decide
“how” to apply those requirements in a bench trial. Kumho
Tire, 526 U.S. at 152. So a district court has leeway about
“whether or when special briefing or other proceedings are
needed to investigate” the facts relevant to qualification and




                                 13
admissibility of expert testimony. Id. Or it may conditionally
admit the expert testimony subject to a later Rule 702
determination. Cf. In re Unisys, 173 F.3d 145, 155-58 (3d Cir.
1999) (“When the role of the gatekeeper to admit or exclude
evidence (the judge) and the role of the factfinder to assess and
weigh the evidence that was admitted (the jury) are one and the
same, the judge who becomes the factfinder as well as the
gatekeeper must be given great deference by this Court[] and .
. . should not be required to waste judicial time.”). But that “is
not discretion to abandon the gatekeeping function” or
“perform the function inadequately. Rather, it is discretion to
choose among reasonable means of excluding expertise[.]”
Kumho Tire, 526 U.S. at 158–59 (Scalia, J., concurring). That
is why the failure to conduct any form of “assessment” of an
expert and the proposed testimony before admitting the
testimony is an abuse of discretion. Daubert, 509 U.S. at 592–
93; see Padillas v. Stork-Gamco, Inc., 186 F.3d 412, 418 (3d
Cir. 1999). Here, in sidestepping Rule 702 altogether and
declining to perform any assessment of Shearer’s testimony
before trial, the District Court ignored the rule’s clear mandate.
Daubert, 509 U.S. at 592.4


       4
          Some courts go further and suggest that Daubert’s
requirements are “relax[ed]” in the context of bench trials.
David E. Watson, P.C. v. United States, 668 F.3d 1008, 1015
(8th Cir. 2012) (citation omitted); see also, e.g., United States
v. Brown, 415 F.3d 1257, 1268 (11th Cir. 2005) (holding that
Rule 702’s requirements are “more relaxed in a bench trial
situation, where the judge is serving as factfinder and we are
not concerned about dumping a barrage of questionable
scientific evidence on a jury” (internal quotation marks and




                               14
B.     The District Court Abused Its Discretion by Failing
       to Exclude Shearer’s Testimony at Trial

        After the bench trials, the District Court denied UGI’s
renewed requests to exclude Shearer’s testimony. In doing so,
it abused its discretion, as Shearer’s testimony lacked both the
reliability and fit required under Rule 702. We address each of
these requirements in turn.

       1.     Reliability

        Rule 702’s reliability threshold requires expert
testimony to be “based on the methods and procedures of
science, not on subjective belief and unsupported speculation.”
Karlo, 849 F.3d at 80–81 (quoting In re TMI Litig., 193 F.3d
at 703–04). Courts look for rigor, not mere “haphazard,
intuitive inquiry.” Oddi v. Ford Motor Co., 234 F.3d 136, 156
(3d Cir. 2000). Yet admissibility is not based on whether an

citation omitted)). That proposition arguably fights the text of
Rule 702, which applies to all “trier[s] of fact” and imposes
conditions on whether an expert “may testify,” Fed. R. Evid.
702. And it ignores the reality that we “judges lack the
scientific training that might facilitate the evaluation of
scientific claims or the evaluation of expert witnesses who
make such claims.” Stephen Breyer, Introduction to Comm. on
Sci., Tech., and Law, in Reference Manual on Scientific
Evidence 4 (3d ed. 2011). We have yet to address this issue
and, especially as the parties have not raised it, we need not
today. Because even cases applying a “relaxed” standard in
bench trials agree that Rule 702’s requirements of “relevance
and reliability . . . must nevertheless be met.” E.g., Seaboard
Lumber Co. v. United States, 308 F.3d 1283, 1302 (Fed. Cir.
2002). And here, without question, they were not.




                              15
expert’s “opinion has the best foundation, or even whether the
opinion is supported by the best methodology or unassailable
research.” Karlo, 849 F.3d at 81. Rather, “the court looks to
whether the expert’s testimony is supported by ‘good
grounds.’” Id.

       Both the Supreme Court in Daubert and this Court in
many decisions have explained that whether “good grounds”
support an expert’s potential testimony depends on many
factors, including:

       (1) whether a method consists of a testable
       hypothesis; (2) whether the method has been
       subject to peer review; (3) the known or potential
       rate of error; (4) the existence and maintenance
       of standards controlling the technique’s
       operation; (5) whether the method is generally
       accepted; (6) the relationship of the technique to
       methods which have been established to be
       reliable; (7) the qualifications of the expert
       witness testifying based on the methodology;
       and (8) the non-judicial uses to which the method
       has been put.

Pineda, 520 F.3d at 247–48 (citing In re Paoli R.R. Yard PCB
Litig., 35 F.3d 717, 742 n.8 (3d Cir. 1994)). While no one is
dispositive, some analysis of these factors is necessary. Id. at
248. Here, none occurred.

       Take the reports. They lack any suggestion that the
“damaged goods theory” has been subject to peer review or
enjoys general acceptance. Nor do they contain any analysis of
a known or potential rate of error. Or any standards controlling
the theory’s application. Each, instead, comes from Shearer’s




                              16
anecdotal experience in his grandfather’s appliance shop,
where he worked as a sales representative during his high
school and college years. There, Shearer “took part in many
‘scratch and dent’ sales” of goods that “had been slightly
damaged” but were otherwise “as good as any other equal
model that was not affected with any scratch or dent.” (App. at
113; accord App. at 689.) Drawing on this experience, Shearer
observes that “the obvious appraisal question is, [d]id my
grandfather get more, the same, or less for the ‘scratch and
dent’ models than the undamaged models and items?” (App. at
114; accord App. at 689.) He concludes that “the answer is
equally obvious. We all learn early on that consumers will
automatically discount most if not all items and merchandise
that is either damaged in some way or is ‘perceived’ to be
damaged in some way.” (App. at 114; accord App. at 689.) All
of which may be true. But “it is impossible to test a hypothesis
generated by a subjective methodology because the only
person capable of testing or falsifying the hypothesis is the
creator of the methodology.” In re TMI Litig., 193 F.3d at 703
n.144.

       Above all, it is the speculative and subjective nature of
this testimony that severs the necessary relationship to
“methods which have been established to be reliable.” In re
Paoli, 35 F.3d at 742 n.8. Shearer blends his observations on
consumer habits in the appliance market with far-flung
examples of environmental accidents involving nuclear power
and oil transportation. But the two principles—that consumers
prefer undented appliances and property values declined near
the Three Mile Island catastrophe—meet only by assumption.
And it isn’t clear whether the theory rests on analogy to buying
preferences generally, or in the real estate market specifically.
Nor is it clear that Shearer’s conclusions that property value




                               17
decreased near Three Mile Island and the Valdez spill trace to
consumer perception rather than actual, irremediable harm,
because Shearer presented no quantifiable data to explain or
clarify his assumptions. But in any case, there is no data
supporting the application of Shearer’s theory to the
Landowners’ properties.

       Instead, as Shearer explained, “I put this all in my little
mixing bowl and I come up with what I thought was common
sense reasonable[.]” (App. at 336.) His theories on the effect of
stigma on value, he concedes, “can’t be proven. That’s the
problem.” (App. at 985.) We agree that is the problem, and his
testimony is unsupported by “good grounds.”5

       5
           Much of the briefing grappled with “stigma
damages”—damages based on fears of environmental harms
that “decreas[e] the market value of the property,” United
States v. 14.38 Acres of Land, 80 F.3d 1074, 1078–79 (5th Cir.
1996)—in gas pipeline condemnation actions. One amicus
urges us to hold that expert opinions related to stigma damages
are admissible only if based on a particular (and often
unavailable) type of comparative sales data. (Br. of Interstate
Nat. Gas Assocs. of Am. at 18.) But we have no occasion to
reach those broader questions today. UGI concedes that “both
state and federal law provide for such damages as long as there
is competent expert testimony to support them,” UGI’s Letter
Brief at 2, UGI Sunbury LLC v. A Permanent Easement for
1.7575 Acres, No. 18-3126, and UGI Sunbury LLC v. A
Permanent Easement for 0.4577 Acres, No. 18-3127 (3d Cir.
Sept. 4, 2019), and that stigma damages are “part of appraised
value in condemnation cases,” Recording of Oral Argument at
02:30, so long as they satisfy the rigor and fit Rule 702




                               18
       2.     Fit

        To determine whether an expert’s testimony “fits” the
proceedings, this Court asks whether it “will help the trier of
fact to understand the evidence or to determine a fact in issue.”
Fed. R. Evid. 702(a); Karlo, 849 F.3d at 81. “‘Fit’ is not always
obvious, and scientific validity for one purpose is not
necessarily scientific validity for other, unrelated purposes.”
Daubert, 509 U.S. at 591. “Thus, even if an expert’s proposed
testimony constitutes scientific knowledge, his or her
testimony will be excluded if it is not scientific knowledge for
purposes of the case.” Paoli, 35 F.3d at 743 (emphasis in
original).6

        Whatever the relevance of Shearer’s theory generally, it
does not fit the facts here. Consider a colloquy during the
Pontius trial. Shearer agreed his report contained “no examples
of properties whose value actually decreased after installation
of a natural gas pipeline.” (App. at 820.) He agreed his findings
relied partly on properties impacted by radiation leaks and oil
spills, not the installation of a pipeline. He agreed that his

requires. Shearer’s testimony does not, so we leave for a more
appropriate case the question of how future litigants might
successfully prove that claim.
       6
         Another amicus urges us to hold that to be admissible
under Rule 702, evidence of stigma damages “must have a
requisite nexus to the fair market value of the property at
issue.” (Br. of Marcellus Shale Coalition at 8 (emphasis
omitted).) During oral argument, counsel for UGI could
perceive no difference between the “nexus” requirement urged
by amicus and Rule 702’s existing “fit” requirement. Neither
can we.




                               19
report contains leaps of logic, elements of subjectivity, and
even speculation.7

       Aptly, we considered similarly constructed expert
testimony two decades ago in a case arising out of the actual
Three Mile Island accident. There, we explained the
“speculative character” of testimony based on “assumption”
where the expert acknowledged, “I just don’t have enough of a
database to prove details of this.” TMI Litig., 193 F.3d at 670
(emphasis omitted). Shearer’s testimony offers a familiar echo,
explaining “Come back five years from now and I may not
agree with my own opinion. If we find properties that sell with
pipelines down the middle of a farm and sold for the same as
an identical farm down the road, I’m wrong today. But we
don’t have the data.” (App. at 332.) At best, Shearer offered
“the beginning of a discussion and not the end.” TMI Litig.,
193 F.3d at 670. His proposed testimony will not assist the trier
of fact and does not fit the proceedings as the Federal Rules
required.

       Taken together, Shearer’s testimony lacked reliability
and did not fit the case, contravening the mandatory
requirements of Federal Rule of Evidence 702 applicable in
both bench and jury trials. But here the District Court declined
to analyze Shearer’s expert testimony for reliability or fit
before or after trial. And the District Court relied on that
mistakenly admitted evidence to UGI’s detriment in
calculating the compensation owed to the Landowners.



       7
          Although this exchange occurred during the Pontius
trial, the reports and testimony in both cases are nearly
identical.




                               20
C.     These Errors Were Not Harmless

        Finally, one set of landowners urges us to hold that any
Rule 702 errors were harmless. They are not. Excusing a
misapplication of the rules of evidence requires a showing that
“it is highly probable that the error did not affect the outcome
of the case.” GN Netcom, Inc. v. Plantronics Inc., 930 F.3d 76,
88 (3d Cir. 2019). Or, put another way, we must have a “sure
conviction” that an error did not change the outcome. Id.

       Here, there is no doubt the District Court “agree[d] with
Mr. Shearer that there was an overall decrease to the value of
the property . . . at least in part . . . due to the ‘stigma’ of being
located so close to a natural gas pipeline.” (App. at 34; see also
App. at 19 (“[T]his Court is inclined to agree with Mr. Shearer
that some form of ‘stigma’ attaches to the property as a
whole.”).) That alone shows Shearer’s faulty testimony
affected UGI’s “substantial right[s].” Fed. R. Evid. 103(a). So
the admission of that testimony cannot be said to have been
harmless, and we must vacate the judgments.

                 IV. REMAINING ARGUMENTS

       Our conclusion that the District Court abused its
discretion under Rule 702 means we must vacate the judgments
and remand for more factfinding. We briefly address the
parties’ remaining arguments because they are relevant for
future proceedings.

       First, we reject UGI’s argument that on remand, the
District Court may consider “only the competent evidence in
the [existing] record.” (Appellant’s Br. at 41.) Our appellate
jurisdiction includes the authority to remand for “such further
proceedings . . . as may be just under the circumstances.” 28




                                 21
U.S.C. § 2106. Particularly where “confusion and uncertainty
exist[s] as to . . . the correct standard,” it may be “just under
the circumstances” to remand for a new valuation hearing.
Augusta Power Co. v. United States, 278 F.2d 1, 5 (5th Cir.
1960). Such is the case here. Although a district court’s duties
under Rule 702 are well settled, how those duties are applied
in a gas pipeline condemnation bench trial is not. So we instruct
the District Court on remand to allow the parties a reasonable
opportunity, if requested, to produce new valuation evidence.
Evidence subject, of course, to Rule 702 and the other rules of
evidence and procedure.

       Second, while this appeal was pending we held in an
unrelated case that state rather than federal common law
determines just compensation in Natural Gas Act
condemnation proceedings brought by private entities. Tenn.
Gas, 931 F.3d at 255. UGI argues that Tennessee Gas makes
no difference in these appeals. We find that assertion doubtful,
as we have recognized that Pennsylvania law permits recovery
of categories of damages which federal common law does not,
id. at 244, including the “professional fees and expenses”
claimed by at least one set of landowners below. (App. at 951.)
But “[w]e deem it desirable that the District Court, in the first
instance, evaluate the effect of that intervening decision.”
Patterson v. Warner, 415 U.S. 303, 307 (1974) (per curiam).

       Finally, we reject the Landowners’ argument that the
District Court’s findings can satisfy Federal Rule of Civil
Procedure 52. Rule 52(a)(1) imposes a “mandatory
requirement,” In re Frescati Shipping Co., 718 F.3d 184, 196
(3d Cir. 2013), that trial courts “make clear factual findings to
support its conclusions,” Sabinsa Corp. v. Creative
Compounds, LLC, 609 F.3d 175, 182 (3d Cir. 2010).
Conclusory pronouncements are not enough. Rather, a




                               22
conclusion must clearly state the appropriate “subordinate
factual foundations” supporting a decision. Id. (citation
omitted); see also H. Prang Trucking Co. v. Local Union No.
469, 613 F.2d 1235, 1238 (3d Cir. 1980). Otherwise, reviewing
courts are left without “a clear understanding of the basis of the
decision,” which is “necessary to the intelligent and orderly
presentation and proper disposition of an appeal.” In re
Frescati, 718 F.3d at 196 (internal quotation marks and
citations omitted).

       While the District Court provided factual findings and
legal conclusions, the compensation awards were conclusory,
rather than clear, and lacked “factual foundations.” Sabinsa,
609 F.3d at 182; accord H. Prang Trucking, 613 F.2d at 1238.
The District Court determined “[p]art of that decrease in value
was due to the ‘stigma’ associated with having a natural gas
pipeline installed on the property.” (App. at 19, 22, 34, 36.) But
the only basis for a “stigma” decrease is Shearer’s opinion,
testimony the District Court did not fully embrace. As a result,
the findings “render impossible a clear understanding of the
basis of the decision, and those findings are obviously
necessary to the intelligent and orderly presentation and proper
disposition of an appeal.” Frescati, 718 F.3d at 196 (internal
quotation marks and citation omitted).

                       V. CONCLUSION

       The District Court abused its discretion in admitting and
relying on Shearer’s testimony, and its conclusory valuation of
just compensation in both cases lacks a clearly stated basis. We
will vacate the judgments and remand for further proceedings
consistent with this Opinion.




                               23
