Alicia A. Cohen v. Ronald A. Cohen, a/k/a Rafi Cohen a/ka Rafael Cohen a/k/a Rafa-El Cohen a/k/a Rafael…

PRECEDENTIAL
UNITED STATES COURT OF APPEALS
FOR THE THIRD CIRCUIT
_____________
No. 21-2997
_____________
ALICIA A. COHEN
v.
RONALD A. COHEN,
a/k/a Rafi Cohen
a/ka Rafael Cohen
a/k/a Rafa-El Cohen
a/k/a Rafael Chaim Ha Cohen
a/k/a Rafael Chaim Cohen
a/k/a Ron Cohen
a/k/a Ronnie Cohen,
Ronald A. Cohen,
Appellant
_____________
On Appeal from the United States District Court for the
District of Delaware
(D.C. Civil No. 1:19-cv-01219)
District Judge: Honorable Maryellen Noreika
____________
Argued July 30, 2024
Before: KRAUSE, RESTREPO, and MATEY, Circuit Judges
(Filed: January 8, 2025)
_____________
Steven L. Caponi
Matthew B. Goeller
K&L Gates
600 N King Street, Suite 901

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Wilmington, DE 19801
David R. Fine [ARGUED]
Amy L. Groff
K&L Gates
17 N Second Street, 18th Floor
Harrisburg, PA 17101
Counsel for Appellee
Ronald A. Cohen
Apartment 204
2171 Britton Road
Leland, NC 28451
Pro Se Appellant
Stephen A. Fogdall [ARGUED]
Dilworth Paxson
1500 Market Street, Suite 3500E
Philadelphia, PA 19102
Court Appointed Amicus Curiae
___________
OPINION OF THE COURT
____________
MATEY, Circuit Judge.
A woman sued her father alleging childhood sexual
abuse and supported her claims with expert testimony
describing the accuracy of “recovered” memories. Because the
District Court abused its discretion by failing to analyze the
expert’s qualifications and committed harmful error in
admitting his testimony, we will vacate the judgment.
I.
Alicia A. Cohen alleged that her father, Ronald A.
Cohen, began sexually abusing her at the age of three. The
alleged attacks stopped in 1992, and by 1995, Ms. Cohen no
longer recalled the abuse. Eighteen years later, Ms. Cohen
“[g]radually” developed “confusing” memories about her
childhood. App. 1354, 1455. Ms. Cohen “live[d] in the same

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area [where she] was abused” and would experience
“emotional sensations and physical sensations” as she was
“going about the community.” App. 1354. She would then “try
to figure out how to make sense of” these “jumbled up”
memories. App. 1354. Eventually, her recollections crystalized
into the allegations she filed against Mr. Cohen six years later
for human trafficking, sexual abuse, assault, emotional
distress, false imprisonment, and incest under federal and state
law. She asserted that her claims were timely because she
“repressed her thoughts and memories of” the abuse. App. 148.
In preparation for trial, Mr. Cohen designated Dr. Deryn
Strange as an expert to testify on human memory. Dr. Strange
explained in her report that “normal human memory is a
reconstructive process” in which memories can be altered
when individuals “incorporate other details into our memory
that we did not see or experience.” App. 319–20. According to
Dr. Strange, there is “no scientific support” for the theory that
“trauma victims can repress and then later recover memory for
trauma” containing “all the clarity and detail of the original
experience.” App. 325–26. Based on her review of discovery
materials, Dr. Strange concluded that Ms. Cohen “created false
memories of abuse.” App. 343.
Ms. Cohen designated Dr. James Hopper to respond,
because, according to Dr. Hopper, while “memories generally
fade,” individuals “typically remember the gist of what
happened and some of the most central details.” App. 291–92.
And “the phenomena of what are known colloquially as
‘repressed’ and ‘recovered’ memories are well-established
facts,” as shown by the inclusion of “dissociative amnesia” in
“the field of psychiatry’s ‘diagnostic bible,’ the Diagnostic and
Statistical Manual” (“DSM”). App. 295. Dr. Hopper stressed
that “there is no evidence that recovered memories are less
accurate than continuous memories, but there is evidence for
no difference in accuracy.” App. 296.
Mr. Cohen moved to exclude Dr. Hopper’s expert report
and testimony, arguing in part “that repressed memory is no
longer a generally accepted theory among the current scientific
community.” App. 272. He also argued that Dr. Hopper’s
theory of repressed memory “undermines . . . the idea that
someone could completely suppress all memory of sex abuse

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for any extended period of time,” as Ms. Cohen claimed.
App. 277. After a hearing, the District Court granted the
motion in part and denied it in part.1 Resolving to “put [Drs.
Strange and Hopper] on the same level,” the District Court
concluded that if Dr. Strange testified “that repressed
memories aren’t real,” Dr. Hopper could “say sometimes they
are.” App. 31–32.
At trial, Mr. Cohen’s counsel “object[ed] to the
qualification [of Dr. Hopper] as an expert witness.” App. 1622.
But the District Court “qualif[ied] him as an expert,” reasoning
that these objections went “more to credibility than to his
expertise.” App. 1622. Dr. Hopper then testified that children
who suffer abuse will repress memories “because to relive
[them] is going to evoke emotions that are going to make it
harder for [the victim] to connect with and survive with the
caregiver.” App. 1641. He also testified that “freely recall[ed]”
memories, which occur when an individual is asked “what do
you remember about [a particular] experience,” are “85 to 95
percent accurate.” App. 1652. Dr. Hopper contrasted this form
of memory recovery with “research [that] boils down to lying
to people and forcing them to answer questions about things
they don’t remember.” App. 1651–52. During closing
argument, Ms. Cohen’s counsel reminded the jury that even if
Ms. Cohen was “mistaken in some of the details,” Dr. Hopper
had testified that “the central details of what happened, are . . .
maybe as much as 90 percent accura[te].” App. 1699–700.
The jury returned a mixed verdict, finding for Ms.
Cohen on five state law counts and awarding her $1.5 million
in compensatory and punitive damages. Mr. Cohen,
proceeding pro se, appealed the District Court’s final
judgment, and we appointed amicus counsel on his behalf.
1 During the hearing, the District Court also ruled on Mr.
Cohen’s motions to exclude the reports and testimony of Ms.
Cohen’s experts on child abuse and human trafficking and her
treating physicians’ testimony, as well as Ms. Cohen’s motion
to partially exclude Dr. Strange’s report and testimony.

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Seeing prejudicial error in the District Court’s decision, we
will vacate and remand.2
II.
Rule 702 contains “three distinct substantive
restrictions on the admission of expert testimony:
qualifications, reliability, and fit.”3 Elcock v. Kmart Corp., 233
F.3d 734, 741 (3d Cir. 2000). District courts are tasked with a
“rigorous gatekeeping function,” id. at 744, to ensure that
1) the expert is qualified; 2) the proposed testimony is reliable
and concerns matters requiring scientific, technical, or
specialized knowledge; and 3) the expert’s testimony is
“sufficiently tied to the facts of the case,” Daubert v. Merrell
Dow Pharms., Inc., 509 U.S. 579, 591 (1993) (quoting United
States v. Downing, 753 F.2d 1224, 1242 (3d Cir. 1985)), so that
it “fit[s]” the dispute and “will assist the trier of fact,” id. See
UGI Sunbury LLC v. A Permanent Easement for 1.7575 Acres,
949 F.3d 825, 832 (3d Cir. 2020).
This gatekeeping function is necessarily “flexible,”
Daubert, 509 U.S. at 594, granting district courts “latitude in
deciding how” these requirements are met, Kumho Tire Co. v.
Carmichael, 526 U.S. 137, 152 (1999). Such “discretionary
2 The District Court had jurisdiction under 28 U.S.C.
§§ 1331, 1367 and we have jurisdiction under 28 U.S.C.
§ 1291. We review the District Court’s decision to admit expert
testimony for an abuse of discretion, United States v. Williams,
974 F.3d 320, 358 (3d Cir. 2020), and will reverse if there “is
a definite and firm conviction that the court below committed
a clear error of judgment in the conclusion it reached upon a
weighing of the relevant factors,” Pineda v. Ford Motor Co.,
520 F.3d 237, 243 (3d Cir. 2008) (quoting In re TMI Litig., 193
F.3d 613, 666 (3d Cir. 1999), amended by 199 F.3d 158
(2000)). Upon a finding of abuse, “we review de novo whether
that error was prejudicial or harmless.” United States v.
Schneider, 801 F.3d 186, 200 (3d Cir. 2015). Otherwise, we
exercise plenary review over the District Court’s legal
interpretation of Federal Rule of Evidence 702. Karlo v.
Pittsburgh Glass Works, LLC, 849 F.3d 61, 81 (3d Cir. 2017).
3 Like the District Court, we apply the version of Rule
702 in force at the time of trial.

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authority” permits a district court to “decide whether or when
special briefing or other proceedings are needed to investigate
reliability.” Kumho Tire Co., 526 U.S. at 152. True, a district
court “may conditionally admit the expert testimony subject to
a later Rule 702 determination.” UGI Sunbury, 949 F.3d at 833.
But this leeway “is not discretion to abandon the gatekeeping
function” or “perform the function inadequately.” Kumho Tire,
526 U.S. at 158–59 (Scalia, J., concurring).
Although a district court has “an independent obligation
to reach a decision upon a record that had been adequately
developed,” Oddi v. Ford Motor Co., 234 F.3d 136, 153
(3d Cir. 2000), the flexible nature of this framework allows
district courts to issue rulings absent formal findings of fact
when working from an extensive record, see, e.g., United
States v. Mitchell, 365 F.3d 215, 233–34 (3d Cir. 2004)
(explaining that the absence of factual findings did not require
a different standard of review where the district court “assessed
extensive live testimony” over a five-day Daubert hearing);
Oddi, 234 F.3d at 153–55 (concluding that a Daubert hearing
was not required because “the evidentiary record . . . was far
from scant” and included “depositions and affidavits of the
plaintiff’s experts”). But a district court should still “take into
account all of the” Daubert factors. In re Paoli R.R. Yard PCB
Litig. (Paoli II), 35 F.3d 717, 742 (3d Cir. 1994). And absent
“a developed record,” a “district court’s decision is wanting” if
“it did not make explicit enough findings.” In re Paoli R.R.
Yard PCB Litig. (Paoli I), 916 F.2d 829, 858 (3d Cir. 1990);4
see UGI Sunbury, 949 F.3d at 833; Padillas v. Stork-Gamco,
Inc., 186 F.3d 412, 417–18 (3d Cir. 1999).
The District Court’s process fell short of the rigor
required by Daubert and Rule 702.5 The Court dispatched four
4 Although decided before Daubert, Paoli I applied
Rule 702 as explained in Downing, which “remains good law.”
United States v. Brownlee, 454 F.3d 131, 142 n.10 (3d Cir.
2006). 5 Ms. Cohen claims that Mr. Cohen “waived or forfeited
. . . the Daubert objections now being made” because his
motion focused on “Dr. Hopper’s alleged endorsement of the
theory of ‘repressed memory.’” Amicus Response Br. 26–27.

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Daubert motions in a single hearing that lasted just over an
hour, with less than thirty minutes devoted to the combined
discussion of Drs. Strange and Hopper. The short attention on
Dr. Hopper centered on how his testimony would respond to
Dr. Strange. There was no engagement with the arguments
raised by Mr. Cohen in his Daubert motion as to the reliability
and fit of Dr. Hopper’s testimony. Instead, the District Court
chose to “put [Drs. Strange and Hopper] on the same level” so
that if Dr. Strange testified “that repressed memories aren’t
real,” Dr. Hopper could “say sometimes they are.” App. 31–32.
Ms. Cohen contends that the District Court cannot be
faulted for defaulting to a level playing field, arguing it applies
our “parity principle.” Amicus Response Br. 45–46 (quoting
Mitchell, 365 F.3d at 247). Not so. True, “[i]f one side can offer
expert testimony, the other side may offer expert testimony on
the same subject to undermine it.” Mitchell, 365 F.3d at 247;
see id. at 247–51 (explaining and applying the parity principle
announced in United States v. Velasquez, 64 F.3d 844, 852 (3d
Cir. 1995)). But this is not an alternate path past Daubert’s
gate, as the proponent of the testimony must still be “offering
a qualified expert with good grounds to support his criticism.”
Id. at 247. A district court’s gatekeeping responsibilities are not
negated by the existence of an opposing expert, nor can a
district court delegate its duty to the parties.
The District Court’s assumption that “if we’re talking
about the repressed memories” then “the rules should apply to
both” Drs. Strange and Hopper, without first evaluating their
independent qualifications, is unsupported by the text of Rule
702 or our caselaw. App. 19. By “sidestepping Rule 702
altogether and declining to perform any assessment of”
Dr. Hopper and his testimony independent from that of
Dr. Strange, “the District Court ignored the rule’s clear
But Mr. Cohen’s Daubert motion argued that Dr. Hopper’s
testimony fell short of the reliability and fit requirements. And
after conducting voir dire before the jury, Mr. Cohen’s counsel
“object[ed] to the qualification [of Dr. Hopper] as an expert
witness.” App. 1622. These questions are accordingly
preserved for our review.

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mandate.” UGI Sunbury, 949 F.3d at 833. Accordingly, the
District Court improperly qualified Dr. Hopper as an expert.
III.
Applying the gatekeeping requirements required for
expert testimony, we conclude that Dr. Hopper’s testimony
lacked both the reliability and fit required under Rule 702.6 We
address each of these requirements in turn.
A.
Daubert’s reliability requirement ensures that an
expert’s testimony is “based on the methods and procedures of
science, not on subjective belief and unsupported speculation.”
Karlo v. Pittsburgh Glass Works, LLC, 849 F.3d 61, 80–81 (3d
Cir. 2017) (quoting In re TMI Litig., 193 F.3d 613, 704 (3d Cir.
1999), amended by 199 F.3d 158 (2000)). But admissibility
does not hinge on “whether a particular scientific opinion has
the best foundation, or even whether the opinion is supported
by the best methodology or unassailable research.” Id. at 81
(quoting In re TMI Litig., 193 F.3d at 665). The court instead
“looks to whether the expert’s testimony is supported by ‘good
grounds.’” UGI Sunbury, 949 F.3d at 834 (quoting Karlo, 849
F.3d at 81). This inquiry “applies to all aspects of an expert’s
testimony: the methodology, the facts underlying the expert’s
opinion, [and] the link between the facts and the conclusion.”
ZF Meritor, LLC v. Eaton Corp., 696 F.3d 254, 291 (3d Cir.
2012) (alteration in original) (quoting Heller v. Shaw Indus.,
Inc., 167 F.3d 146, 155 (3d Cir. 1999)).
While there is no “definitive checklist or test,” Daubert,
509 U.S. at 593, “good grounds” supporting an expert’s
testimony include:
(1) whether a method consists of a testable hypothesis;
(2) whether the method has been subject to peer review;
6 Mr. Cohen also contends that Dr. Hopper was
unqualified to render an expert opinion. Because our analysis
rests on factors other than Dr. Hopper’s qualifications, we need
not decide whether Dr. Hopper was qualified to serve as an
expert.

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(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.
UGI Sunbury, 949 F.3d at 834 (quoting Pineda v. Ford Motor
Co., 520 F.3d 237, 247–48 (3d Cir. 2008)). Although no single
factor “is dispositive, some analysis of these factors is
necessary.” Id. The District Court did not mention these
factors, let alone engage with them. Applying them now, we
conclude that Dr. Hopper’s testimony is unsupported by “good
grounds.”
Consider Dr. Hopper’s report, in which he points to the
DSM’s inclusion of “dissociative amnesia” as evidence that
“‘repressed’ and ‘recovered’ memories are well-established
facts.” App. 295. As Dr. Hopper explained, dissociative
amnesia is the “inability to remember important biographical
information, auto[-]biographical information, usually of a
stressful or traumatic nature that is inconsistent with ordinary
forgetting.” App 1645–46. But general acceptance of
dissociative amnesia does not establish the same with respect
to the accuracy of recovered memories. For “if one argued that
the inclusion of dissociative amnesia in [the DSM]
demonstrated acceptance of repressed memory, it would be
analogous to saying that by recognizing the diagnosis of
‘hoofed mammals,’ one was demonstrating the acceptance of
unicorns.”7
Also without basis is Dr. Hopper’s claim that “there is
no evidence that recovered memories are less accurate than
continuous memories, but there is evidence for no difference
in accuracy.” App. 296. For support, he cited two almost
thirty-year-old studies. The 1995 study outlined preliminary
evidence to suggest that recovered memories are as consistent
as continuous memories when the victim reported the abuse in
7 2 David L. Faigman et al., Modern Scientific
Evidence: The Law and Science of Expert Testimony § 19:22
(2024–2025 ed.).

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childhood and afterward underwent a physical examination.8
But it is unclear when and to what degree Ms. Cohen reported
her abuse, and there is no record of a contemporaneous
physical examination. The 1996 study found that the same
percentage of continuous and recovered memories of abuse
had at least one piece of evidence to support their accuracy.9
And while “experts commonly extrapolate from existing data,”
here “there is simply too great an analytical gap between [these
studies] and the opinion proffered” by Dr. Hopper that
recovered memories are just as accurate as continuous
memories. Gen. Elec. Co. v. Joiner, 522 U.S. 136, 146 (1997).
8 This study consisted of 129 women who experienced
childhood sexual abuse and reported the abuse in childhood, at
which time they were physically examined by a medical
provider. Eighty of those women recalled the abuse when
interviewed seventeen years later. Seventy-five of those
women were asked additional questions, and twelve women
from that sample, or 16%, recalled experiencing “a time when
they did not remember that [the abuse] had happened to them.”
Add. 8. The study found that “the women with recovered
memories had no more inconsistencies in their accounts than
did the women who always remembered,” Add. 12, but warned
that “[c]hildren who never reported may have a different
pattern of remembering and forgetting the abuse,” Add. 21.
The author speculated that “accurate recovered memories may
be more likely in this sample” because each participant’s
“abuse was reported in childhood” so that “[w]hen memories
began to resurface, these women may have found it easier to
retrieve an accurate account of the incident.” Add. 21.
9 This study involved seventeen women who, while in
therapy with the author, reported continuous and recovered
memories of abuse perpetrated by their fathers. Each memory
of abuse was broken into constituent facts, and the patients and
fathers gathered evidence to confirm the memories. A
six-person panel reviewed the evidence and rated it for
accuracy. The author concluded that “[o]f those memories for
which some evidence was submitted,” “74.6% of continuous
and 74.7% of recovered memories were judged by the full set
of raters as having at least one piece of” supporting evidence.
Add. 42.

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The probative value of these studies is further weakened
by their relatively small sample sizes. Though there is no
one-size-fits-all for study sizes under Daubert’s reliability
prong, see Mitchell, 365 F.3d at 236 n.16 (explaining that a
sample of 50,000 fingerprints, which is “quite large, and
doubtless would be adequate in many if not most
circumstances,” may not be sufficient “out of about 60 billion
in the world”), the seventeen-person sample in the 1996 study
is insufficient.10 Indeed, the author of the 1995 study, which
was more than seven times the size of the 1996 study,
cautioned that its “statistical analyses must be considered
preliminary” because the study “relied on a small sample.”
Add. 21.
Nor is Dr. Hopper’s testimony that “research over and
over again shows that” memories “freely recall[ed]” are “85 to
95 percent accurate” substantially supported by the research he
cited.11 App. 1652. Dr. Hopper did not elaborate on the
“research” underpinning his conclusory statement. And despite
Ms. Cohen’s efforts to identify studies supporting this claim,
Dr. Hopper cited none of them in his report and therefore
cannot be credited with relying on them.
Taken together, Dr. Hopper’s testimony was
unsupported by “good grounds” that would demonstrate
reliability.
10 This study’s use of an “intra-subject approach,” in
which the accuracy of a participant’s continuous memory was
compared to that of her recovered memory, also raises
questions about the study’s controlling standards. Add. 33; see
Daniel Brown et al., Recovered Memories: The Current Weight
of the Evidence in Science and in the Courts, 27 J. Psychiatry
& L. 5, 74 (1999) (explaining that the participants in the 1996
study “served as their own controls”).
11 The record before us includes Dr. Hopper’s trial
testimony, which was not before the District Court during the
Daubert hearing. Working from a cold record, and without the
benefit of live testimony, we will utilize Dr. Hopper’s trial
testimony in considering its reliability and fit. See UGI
Sunbury, 949 F.3d at 831; Elcock, 233 F.3d at 746.

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B.
An expert’s testimony “fits” the proceedings, if it “will
help the trier of fact to understand the evidence or to determine
a fact in issue.” Fed. R. Evid. 702(a); see UGI Sunbury, 949
F.3d at 835. “‘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. “This condition
goes primarily to relevance,” Karlo, 849 F.3d at 81 (quoting In
re TMI Litig., 193 F.3d at 663), so an expert’s “testimony will
be excluded if it is not scientific knowledge for purposes of the
case,” UGI Sunbury, 949 F.3d at 835 (quoting Paoli II, 35 F.3d
at 743).
Dr. Hopper’s testimony that “freely recall[ed]”
memories are “85 to 95 percent accurate” does not fit the facts
here. App. 1652. Ms. Cohen did not testify that she recalled
any memories of abuse because of someone else’s questions.
Indeed, she never “remember[ed] an incident of abuse because
of something” her therapist said. App. 1355. Rather, Ms.
Cohen “would be going about the community” and experience
“emotional sensations and physical sensations” that she would
then “have to try to figure out.” App. 1354. But those instances
of recollection are not emblematic of “free recall.”
Nor is Dr. Hopper’s general theory of memory
repression applicable to this case. He testified that abuse
victims repress memories “because to relive [them] is going to
evoke emotions that are going to make it harder for [the victim]
to connect with and survive with the caregiver.” App. 1641.
But rather than try to “connect with” Mr. Cohen, App. 1641,
Ms. Cohen testified that she was “disgusted and revolted by
him,” App. 1351, and had “hated [her] father since [she] was
four years old,” App. 1439. Indeed, Ms. Cohen “didn’t want to
be around [Mr. Cohen],” “didn’t want to spend time with him,”
and “would throw horrible tantrums” to avoid being with him.
App. 1345.
In sum, Dr. Hopper’s testimony lacked reliability and
fit, contravening the requirements of Rule 702. The District
Court erred in failing to analyze these core components before
admitting his testimony.

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C.
An evidentiary error is harmless “when it is highly
probable that it did not prejudice the outcome.” United States
v. Scarfo, 41 F.4th 136, 174 (3d Cir. 2022) (quoting United
States v. Schneider, 801 F.3d 186, 200 (3d Cir. 2015)). The
District Court’s admission of Dr. Hopper’s testimony was
prejudicial.
During closing argument, Ms. Cohen’s counsel
contended that although Ms. Cohen could “be mistaken in
some of the details,” Dr. Hopper’s testimony made clear that
“the central details of what happened, are strong and accurate”
with “maybe as much as 90 percent accuracy.” App. 1699–700.
On this record, we cannot conclude that “the error did not affect
the jury’s verdict.” Hirst v. Inverness Hotel Corp., 544 F.3d
221, 228 (3d Cir. 2008); see Barker v. Deere & Co., 60 F.3d
158, 165 (3d Cir. 1995) (finding prejudicial error in admission
of improper evidence in part because plaintiff’s “opening
statement and closing argument contained references to” the
improperly admitted evidence). Accordingly, we must vacate
the judgment and remand for a new trial.
* * *
The District Court abused its discretion in admitting Dr.
Hopper’s testimony without analyzing its reliability or fit and
the admission caused prejudicial error. So we will vacate the
judgment and remand for further proceedings.

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