[J-41-2020]

IN THE SUPREME COURT OF PENNSYLVANIA

EASTERN DISTRICT

SAYLOR, C.J., BAER, TODD, DONOHUE, DOUGHERTY, WECHT, MUNDY, JJ.

COMMONWEALTH OF PENNSYLVANIA,

Appellee

v.

RUSSELL COX,

Appellant

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No. 783 CAP

Appeal from the Order entered on 

June 24, 2019 in the Court of 

Common Pleas, Philadelphia 

County, Criminal Division at No. CP51-CR-0511561-1986.

SUBMITTED: April 9, 2020

OPINION

JUSTICE WECHT DECIDED: October 21, 2020

On March 26, 2019, we remanded this capital appeal to the PCRA1 court for further 

consideration of Russell Cox’s claim that, due to his intellectual disability,2the Eighth 

Amendment to the United States Constitution and the Supreme Court of the United 

States’ decision in Atkins v. Virginia, 536 U.S. 304 (2002), precluded him from being 

sentenced to death.

3

 Upon remand, the PCRA court reconsidered the record and again 

 

1 Post Conviction Relief Act, 42 Pa.C.S. §§ 9541-46.

2 At the time that Atkins v. Virginia, 536 U.S. 304 (2002), was decided, the prevailing 

terminology in the medical, professional, and legal community was “mental retardation.” 

Id. at 317. However, since that time, the term has been replaced with “intellectual 

disability.” See Hall v. Florida, 572 U.S. 701, 704 (2014); Commonwealth v. Thomas, 215 

A.3d 36, 44 n.10 (Pa. 2019). Accordingly, except when directly quoting from precedents, 

transcripts, or sources, we will use the term “intellectual disability” or “intellectually 

disabled.”

3 Commonwealth v. Cox, 204 A.3d 371, 392 (Pa. 2019) (“Cox III”). Chief Justice 

Saylor and Justices Baer and Todd did not participate in Cox III. Otherwise, the decision 

to remand Cox’s appeal was unanimous. We discuss the particulars of the causes for 

our remand in detail below.
[J-41-2020] - 2

determined that Cox had failed to establish that he was entitled to relief. We vacate that 

ruling, and we remand the case to the PCRA court for further proceedings.

I.

Before proceeding to the background of this case, it is necessary first to outline 

briefly the law concerning capital punishment and intellectually disabled persons, 

beginning with the complete ban on the execution of such individuals, and ending with 

the standards that have developed in the U.S. Supreme Court and in this Court for 

classifying a capital defendant as intellectually disabled.

The Eighth Amendment forbids, inter alia, the infliction of “cruel and unusual 

punishments.” U.S. CONST. amend. VIII. This prohibition restrains the federal 

government as well as the States through application of the Fourteenth Amendment. 

Robinson v. California, 370 U.S. 660, 666-67 (1962). By prohibiting inhumane treatment 

of even those who have committed the most serious crimes, “the Eighth Amendment 

reaffirms the duty of the government to respect the dignity of all persons.” Roper v. 

Simmons, 543 U.S. 551, 560 (2005); see also Trop v. Dulles, 356 U.S 86, 100 (1958) 

(“The basic concept underlying the Eighth Amendment is nothing less than the dignity of 

man.”). To enforce this mandate, the Supreme Court has weighed each contested form 

of punishment against the “evolving standards of decency that mark the progress of a 

maturing society.” Trop, 356 U.S. at 101.

In Atkins, the Supreme Court applied this test in assessing the constitutionality of 

executing intellectually disabled individuals. Atkins, 536 U.S. at 311-12, 321. Marking a 

significant jurisprudential shift from Penry v. Lynaugh, 492 U.S. 302 (1989)4—the lone 

 

4 Atkins’ holding wholly abrogated Penry, in which the Court previously had declined 

to conclude, in the absence of a national consensus, that “the Eighth Amendment 

precludes the execution of [a] mentally retarded person . . . convicted of a capital offense 

simply by virtue of his or her mental retardation alone.” 492 U.S. at 340. See Atkins, 536 

U.S. at 321; see also Matthew Debbis, Note, The Cruel and Unusual Punishment Clause 
[J-41-2020] - 3

precedent on this question at the time—the Supreme Court discerned a national 

consensus against the execution of this category of offenders. The Court observed that, 

in Penry’s wake, State legislatures began prohibiting the practice by statute. 

Notwithstanding the significance of the sheer number of States to have adopted these 

laws, the Court found “the consistency of the direction of change” toward prohibition to be 

even more representative of our society’s evolving standards of decency. Atkins, 536 

U.S. at 314-15.

In addition to the emerging consensus against executing intellectually disabled 

persons, the Court identified two compelling reasons that bolstered its view that executing 

such persons violated the Eighth Amendment. First, executing intellectually disabled

individuals would not promote the traditional goals of punishment. The Court opined that 

the sanction does not support a deterrent aim, as those who fall within this category of 

offenders have a “diminished ability to understand and process information, to learn from 

experience, to engage in logical reasoning, or to control impulses,” all of which renders

those individuals less likely to be able to “process the information of the possibility of 

execution as a penalty and, as a result, control their conduct based upon that information.” 

Id. at 320. As to retribution, the Court similarly determined that the limited mental capacity 

attendant to intellectual disability lessens the offender’s moral culpability and, thus, the 

retributive justification for capital punishment. Id. at 319.

Second, the Court explained that the execution of intellectually disabled individuals 

impairs the integrity of the trial process, inasmuch as such individuals “face a special risk 

of wrongful execution.” Id. at 320-21. Specifically, the Court pointed to the increased 

likelihood that an intellectually disabled person would falsely confess, provide incorrect or 

 

of the Eighth Amendment Prohibits the Execution of Mentally Retarded Defendants: 

Atkins v. Virginia, 41 DUQ. L. REV. 811, 834 (2003).
[J-41-2020] - 4

unconvincing testimony as a witness, and be unable to assist his or her attorney during 

critical phases of the trial. Id.

Combined with the growing national consensus, these dual concerns drove the 

Supreme Court’s holding that the Eighth Amendment categorically precludes executing 

intellectually disabled offenders. Notwithstanding three dissenting votes and two written 

dissents, see id. at 321-28 (Rehnquist, C.J., dissenting); 337-54 (Scalia, J., dissenting),

5

the Atkins Majority doubted the existence of any “serious disagreement about the 

execution” of intellectually disabled offenders. Id. at 317. To the extent that there was

such disagreement, however, the Court believed that it would arise “in determining which 

offenders are in fact [intellectually disabled].” Id. The Court offered no guidance to ease 

the all-but-certain difficulties that would result when States began attempting to identify 

the offenders who fell on each side of this new constitutional demarcation. Instead, the 

Court left “to the State[s] the task of developing appropriate ways to enforce the 

constitutional restriction upon [their] execution of sentences.” Id. (quoting Ford v. 

Wainwright, 477 U.S. 399, 416-17 (1986)).

This Court picked up that baton in Commonwealth v. Miller, 888 A.2d 624 (Pa. 

2005). There, for the first time we defined “intellectual disability” for purposes of 

implementing Atkins’ ban. See supra n.2. We began by noting that the Atkins Court itself 

identified two viable options for adjudicating the mental status of a defendant. The first 

option was provided by the American Association of Mental Retardation (“AAMR”), which

defined intellectual disability as a “disability characterized by significant limitations both in 

intellectual functioning and in adaptive behavior as expressed in the conceptual, social, 

and practical adaptive skills.” Id. at 629-30 (quoting AAMR’s MENTAL RETARDATION:

 

5 Chief Justice Rehnquist and Justice Scalia joined each other’s dissenting opinions. 

Justice Thomas joined both dissents as well.
[J-41-2020] - 5

DEFINITION, CLASSIFICATION, AND SYSTEMS OF SUPPORT 1 (10th ed. 2002) (“MENTAL 

RETARDATION”)).

6

 The second came from the American Psychiatric Association’s 

Diagnostic and Statistical Manual of Mental Disorders (4th ed. 1992) (“DSM-IV”), in which

the disability is present when one shows “significantly subaverage intellectual functioning 

(an IQ of approximately 70 or below) with onset before age 18 years and concurrent 

deficits or impairments in adaptive functioning.” Id. at 630 (quoting DSM-IV at 37). We 

discerned three common elements in these two definitions: (1) limited intellectual 

functioning; (2) significant adaptive limitations; and (3) onset before the age of eighteen. 

Id.

Mere identification of the common elements failed to provide a complete definition 

of the term. The first two factors required further elaboration. See id. at 630 n.7 

(explaining that that third factor, age of onset, was self-explanatory and its meaning 

required no further examination). As to the first, this Court recognized that the best way 

to quantify a person’s intellectual functioning is an IQ score. However, we declined to 

“adopt a cutoff IQ score” that would represent per se intellectual disability. Id. at 631. 

Rather, the score is one factor in the overall evaluative scheme. We cautioned that the 

IQ score should not be taken strictly at face value. The score must be adjusted for the 

standard error of measurement (“SEM”)7, which generally “has been estimated to be three 

 

6

In 2007, the AAMR was renamed the American Association on Intellectual and 

Developmental Disabilities (“AAIDD”). See Cox III, 204 A.3d at 376. The eleventh edition 

of the AAIDD’s definition manual was retitled INTELLECTUAL DISABILITY: DEFINITION,

CLASSIFICATION, AND SYSTEMS OF SUPPORT (11th ed. 2010) (“INTELLECTUAL DISABILITY”).

7 A “SEM” is a unit of measurement of confidence in a particularly determination. 

We have explained how the factor works as follows:

1 SEM equates to a confidence of 68% that the measured score falls within 

a given score range, while 2 SEM provides a 95% confidence level. The 

given range for 1 SEM is thus 5 points, within 2 1⁄2 above or below the 

articulated IQ score; the range for 2 SEM is 10 points, within 5 points above 
[J-41-2020] - 6

to five points,” depending upon the specific testing protocol used for the test. Id. at 630 

(citing MENTAL RETARDATION at 57; DSM-IV at 39). Thus, for purposes of the first factor, 

a person may be considered impaired by limited intellectual functioning if he or she has

an IQ score anywhere between 65 and 75 on the Wechsler scales. Id.

We then turned to the second factor, which focuses upon limitations in a person’s 

adaptive behaviors. We explained that adaptive behaviors are the “collection of 

conceptual, social, and practical skills that have been learned by people in order to 

function in their everyday lives.” Id. (citations omitted). Limitations on these basic 

behaviors often are “reflected by difficulties adjusting to ordinary demands made in daily 

life.” Id. (citations omitted). We held that the most reliable and accurate way to evaluate 

a person’s limitations on adaptive behaviors is the use of standardized measures. Using 

such measures, “significant limitations in adaptive behavior” are found when the person’s 

performance “is at least two standard deviations below the mean of either (a) one of the 

following three types of adaptive behavior: conceptual, social, or practical, or (b) an 

overall score on a standardized measure of conceptual, social and practical skills.” Id. at 

630-31 (quoting MENTAL RETARDATION at 14).

Finding that both definitions materially are the same, we declined to choose 

between the two. Thus, to prove that a person is intellectually disabled (or not), “a 

[properly qualified] expert presented by either party may testify as to [intellectual disability] 

under either classification system.” Id. at 631.

In the years after we decided Miller, the Supreme Court issued decisions refining 

its Atkins jurisprudence, beginning in 2014 with Hall v. Florida, 572 U.S. 701 (2014). 

 

or below the IQ score. The larger range logically engenders more 

confidence that it encompasses the relevant IQ.

Commonwealth v. Bracey, 117 A.3d 270, 274 n.6 (Pa. 2015), abrogated on other grounds 

by Moore v. Texas, ___ U.S. ___, 137 S.Ct. 1039 (2017) (cleaned up).
[J-41-2020] - 7

Following Atkins, Hall sought to have his death sentence vacated on the grounds that he 

was intellectually disabled. Id. at 707. Over the course of 40 years, Hall had taken nine

IQ tests that yielded scores between 60 and 80. However, for “evidentiary reasons,” the 

court reviewing Hall’s claim for relief excluded the two scores that fell below 70. Id. Thus, 

Hall’s IQ was assessed as falling between 71 and 80. At the time, Florida statutory law 

erected a strict barrier that prevented any further consideration of a person’s intellectual 

disability if that person’s IQ was above 70. Accordingly, the Supreme Court of Florida 

automatically denied Hall relief. Id.

The U.S. Supreme Court granted certiorari to decide whether Florida’s strict 70-

point threshold was constitutional. Id. After reviewing the governing Eighth Amendment 

principles and summarizing its ruling in Atkins and other germane cases, the Court turned 

to the issue of “how intellectual disability must be defined in order to implement these

[Eighth Amendment] principles and the holding of Atkins.” Id. at 709. To answer the 

question, the Court looked first to “psychiatric and professional studies” to ascertain 

precisely how IQ scores relate to the two other criteria—limited intellectual functioning 

and deficits in adaptive functioning—that Atkins had identified as relevant within the 

medical community’s definition of intellectual disability. Id. After doing so, the Court 

concluded that the Florida statute disregarded established medical standards with regard 

to determination of a person’s intellectual disability in two ways: (1) the statute compelled

a diagnosis upon the strict score cutoff only, whereas medical experts would consider 

other probative evidence; and (2) the statute’s rigid mandate failed to recognize that IQ 

scores are imprecise by nature. Id. at 712. The Court highlighted the fact that, for years, 

experts in the field have applied the SEM to a final assessment of an IQ score. This 

practice more accurately places a person’s IQ score within a range, instead of at a fixed 
[J-41-2020] - 8

point. Florida law precluded such considerations, and its strict threshold prevented 

analysis of any other evidence on the question of intellectual disability. Id. at 713.

The Supreme Court determined that a more flexible standard was consistent both

with the majority approach of other states and with Atkins itself, which recognized the 

inherent imprecision of IQ testing. Id. at 714-18, 719-20. “An IQ score is an 

approximation, not a final and infallible assessment of intellectual functioning.” Id.at 722 

(citation omitted). The Court explained that a numerical score must be viewed in the law 

as it is in the medical community: helpful, but treated with skepticism. “Intellectual 

disability is a condition, not a number,” id. at 723, and should be “informed by the views 

of medical experts,” id. at 721. Thus, “[i]t is not sound to view a single factor as dispositive 

of a conjunctive and interrelated assessment.” Id. at 723. When the IQ score falls within 

the accepted margin of error, the Hall Court held, the Eighth Amendment commands that 

“the defendant must be able to present additional evidence of intellectual disability, 

including testimony regarding adaptive deficits.” Id. at 723.

The Supreme Court promptly revisited its Atkins jurisprudence the next term in 

Brumfield v. Cain, 576 U.S. 305 (2015). Brumfield had been denied an evidentiary 

hearing (and funds to retain an expert) on the Atkins claim he raised during his state postconviction proceedings in Louisiana. Id. at 310. The decision to deny the hearing in large 

part was based upon the post-conviction court’s finding that an IQ score of 75 precluded 

Brumfield from being able to prove that he was intellectually disabled. Id. Brumfield filed 

a federal habeas corpus petition, in which he alleged that the failure to grant a hearing 

based upon this limited view of Atkins “was either ‘contrary to, or involved an 

unreasonable application of, clearly established Federal law, as determined by the 

Supreme Court of the United States,’ or was an ‘unreasonable determination of the facts 

in light of the evidence presented in the State court proceeding.’” Id. at 311 (quoting 28 
[J-41-2020] - 9

U.S.C. § 2254(d)(1), (2)). The District Court agreed with Brumfield on both assertions. 

The United States Court of Appeals for the Fifth Circuit reversed.

The Supreme Court granted certiorari and reversed the Court of Appeals, finding 

that the state court’s denial of an evidentiary hearing was an “unreasonable determination 

of the facts” within the meaning of Section 2254(d)(2). Id. at 313. First, the Court 

explained, Brumfield’s IQ score of 75 was within two standard deviations of the mean as 

established by Louisiana law and within the range articulated in Atkins (70-75). Id. at 315. 

More importantly for present purposes, the ruling below also contravened the Court’s 

mandate in Hall “that it is unconstitutional to foreclose ‘all further exploration of intellectual 

disability’ simply because a capital defendant is deemed to have an IQ above 70.” Id.

(quoting Hall, 572 U.S. at 704). Second, the Court determined that the state postconviction court had unreasonably ignored information offered by Brumfield that showed 

his impairment in adaptive skills. Id. at 317-20. Considering the record as a whole, and 

cognizant that Brumfield only had to raise a reasonable doubt about his intellectual 

disability to obtain a hearing, the Court held that the lower courts had improperly

construed the facts, and that Brumfield was entitled to a hearing before the state court. 

Id. at 322.

Two years later, in Moore v. Texas, ___ U.S. ___, 137 S.Ct. 1039 (2017), the 

Supreme Court reviewed a sentence of death upheld by the Texas Court of Criminal 

Appeals (“CCA”) based upon the application of factors it had developed by in Ex parte 

Briseno, 135 S.W. 3d 1 (Tex. Crim. App. 2004).8 Initially, a Texas post-conviction court 

 

8 Briseno set forth a series of factors to guide Texas courts in the subjective 

assessment of criteria pertaining to a person’s adaptive behavior, as follows:

Did those who knew the person best during the developmental stage—his 

family, friends, teachers, employers, authorities—think he was mentally 

retarded at that time, and, if so, act in accordance with that determination?
[J-41-2020] - 10

held that Bobby James Moore had demonstrated that he was intellectually disabled and 

thus ineligible for the death penalty. Finding that the Briseno factors weighed heavily 

against Moore, the CCA reversed the lower court. Moore, 137 S.Ct. at 1044.

The Supreme Court reversed the CCA, and invalidated Texas’ practice of relying 

upon the Briseno factors. The Court explained that, in Hall, it held that determinations of 

whether a person is intellectually disabled must be “informed by the views of medical 

experts.” Id. (quoting Hall, 572 U.S. at 721). Because each of the seven Briseno factors 

eschewed medical expertise for subjective considerations, the Court reasoned that they

did not comport with Hall’s clear command insofar as they effectively gave “courts leave 

to diminish the force of the medical community’s consensus.” Id. Characterizing many 

of the factors as “invention[s] of the CCA untied to any acknowledged source,” id., the 

Court concluded that “the Briseno factors ‘create an unacceptable risk that persons with 

intellectual disability will be executed,’ and thus “may not be used . . . to restrict 

 

Has the person formulated plans and carried them through or is his conduct 

impulsive?

Does his conduct show leadership or does it show that he is led around by 

others?

Is his conduct in response to external stimuli rational and appropriate, 

regardless of whether it is socially acceptable?

Does he respond coherently, rationally, and on point to oral or written 

questions or do his responses wander from subject to subject?

Can the person hide facts or lie effectively in his own or others' interests?

Putting aside any heinousness or gruesomeness surrounding the capital

offense, did the commission of that offense require forethought, planning, 

and complex execution of purpose?

Briseno, 135 S.W. 3d at 8-9.
[J-41-2020] - 11

qualification of an individual as intellectually disabled.” Id. (quoting Hall, 572 U.S. at 704)

(cleaned up).

In Cox III, we summarized the Supreme Court’s Moore decision as follows:

The Court again re-affirmed its holding in Hall. “Hall indicated that being 

informed by the medical community does not demand adherence to 

everything stated in the latest medical guide. But neither does our 

precedent license disregard of current medical standards.” Moore, 137 

S.Ct. at 1049. The Court also explained that Hall and Brumfield established 

that IQ test scores must be considered while accounting for any SEM. Id.

at 1043. It further explained that “the presence of other sources of 

imprecision in administering the test to a particular individual . . . cannot 

narrow the test-specific standard error range.” Id. at 1049. The Court also 

faulted the [CCA’s] focus on Moore’s adaptive strengths [when the medical 

community focuses upon adaptive deficits]. It noted, “[c]linicians . . . caution 

against reliance on adaptive strengths developed in a ‘controlled setting’ as 

prison surely is.” Id. at 1050. The Court disapproved of the [CCA’s] 

conclusion that Moore’s traumatic childhood contraindicated a finding of 

disability when, again, clinicians identify traumatic experiences as a risk 

factor for intellectual disability. Id. at 1051. Finally, the Court held that the 

Briseno factors impermissibly substitute a political consensus on who 

should be exempt from the death penalty for objective medical standards. 

Id. The Court noted that the Briseno factors represent an outlying position 

among the states, citing this Court’s [decision in Commonwealth v. Bracey, 

117 A.3d 270 (Pa. 2015)] as another such outlier in authorizing 

consideration of the factors. [Moore, 137 S.Ct.] at 1052. The Court 

reaffirmed its central tenet that “[t]he medical community’s current 

standards supply one constraint on States’ leeway [in enforcing Atkins]. 

Reflecting improved understanding over time . . . current manuals offer the 

best available description of how mental disorders are expressed and can 

be recognized by trained clinicians.” Id. at 1053.

Cox III, 204 A.3d at 377-378 (some internal quotation marks and a footnote omitted).

What has emerged from these precedents is a comprehensive legal framework to 

be used when evaluating claims of intellectual disability under the Eighth Amendment. 

Per Atkins, such individuals are categorically precluded from execution. The 

determination of which individuals fit within that category must be decided by the 

individual states. However, that assessment cannot be based upon only an IQ score

unadjusted for the SEM (Hall; Brumfield). As well, the analysis must focus upon adaptive 
[J-41-2020] - 12

deficiencies, not adaptive strengths (Moore), and must rely heavily upon the current 

expressions and practices of the medical community, rather than upon politically created 

rules divorced from medical expertise (Atkins; Hall; Brumfield; and Moore). With this 

framework in mind, we now return to the case sub judice.

II.

A.

In the early morning hours of February 27, 1986, Cox and Percy Lee gained entry 

into the home of Evelyn Brown and her seventeen-year-old daughter, Tina. Once inside, 

Lee hog-tied Evelyn’s arms and feet behind her back, stuffed a pair of women’s

underwear in her mouth, and then stabbed her forty-eight times, killing her. Lee tied

Tina’s hands behind her back with a shoelace, gagged her, and strung a noose around 

her neck. Cox raped Tina while she was bound in this manner. Thereafter, Lee stabbed 

Tina fifty-three times, killing her as well.

9

Cox and Lee were arrested and charged with a number of offenses related to the 

murders. Following a joint jury trial,10 Cox was convicted of two counts of first-degree 

murder, criminal conspiracy, rape, and possessing an instrument of crime (“PIC”).11 

 

9 We have provided a more detailed recitation of the facts of this case in two prior 

appeals, which included Cox’s admission to participating in all but the actual killings. See

Commonwealth v. Cox, 686 A.2d 1279, 1283-85 (Pa. 1996) (“Cox I”), and Commonwealth 

v. Cox, 863 A.2d 536, 540-42 (Pa. 2004) (“Cox II”). Because the specific facts of Cox’s 

crimes are not material to our ultimate disposition here, and because we have outlined 

them at length in the past, this brief summary is all that is necessary.

10 At trial, Cox sought to persuade the jury to disregard his confession to his role in 

the crimes due to his lack of cognitive functioning, his limited mental capacity, and his 

inability to read. In support of this effort, Cox presented testimony from Dr. Mark 

Molyneux, a school psychologist, who informed the jury that Cox possessed an IQ of 69 

and that he had difficulty reading. See Notes of Testimony (“N.T.”), 5/6/1987, at 1387-

1408.

11 See 18 Pa.C.S. §§ 2502(a); 903; 3121; and 907, respectively.
[J-41-2020] - 13

Following the convictions, the case proceeded to the sentencing phase. After two days 

of testimony, the jury found three aggravating factors: (1) the killings were committed 

during the perpetration of a felony; (2) the offense was committed by means of torture; 

and (3) Cox had been convicted of another offense for which a sentence of life 

imprisonment or death could be imposed.12 The jury simultaneously found three 

mitigating factors: (1) Cox had no significant history of prior criminal convictions; (2) Cox’s 

age at the time of the crimes was eighteen; and (3) there was evidence that fell within the 

catch-all mitigating factor.13 After deliberating, the jury found that the three aggravating 

circumstances outweighed the three mitigating circumstances, and recommended

sentences of death for the murders of both Evelyn and Tina Brown.

On May 22, 1987, the trial court formally sentenced Cox to two death sentences, 

and ordered the sentences to run consecutively. The court additionally sentenced Cox 

to ten to twenty years in prison for rape, to five to ten years in prison for conspiracy, and 

to two and one-half to five years in prison for PIC. The trial court ordered that these 

sentences be served concurrently with Cox’s first death sentence. In a series of postsentence motions, Cox filed numerous claims, each of which the trial court denied. Cox 

appealed his death sentences directly to this Court,14 which we affirmed.15

B.

 

12 See 42 Pa.C.S. §§ 9711(d)(6); 9711(d)(8); and 9711(d)(10), respectively.

13 See 42 Pa.C.S. §§ 9711(e)(1); 9711(e)(4); and 9711(e)(8), respectively.

14 See 42 Pa.C.S. § 722(4); id. § 9711(h)(1) (“A sentence of death shall be subject 

to automatic review by the Supreme Court of Pennsylvania pursuant to its rules.”).

15 See Cox I, 686 A.2d at 1292. Cox sought a writ of certiorari from the Supreme 

Court of the United States. The petition was denied. See Cox v. Pennsylvania, 522 U.S. 

999 (1997) (per curiam).
[J-41-2020] - 14

On December 17, 1997, Cox filed a pro se PCRA petition. The PCRA court 

appointed counsel for Cox, who filed an amended petition. Following a series of motions 

to dismiss filed by the Commonwealth and multiple supplemental amendments by Cox, 

the PCRA court held oral arguments and reviewed the record. Thereafter, the court 

issued a notice of intent to dismiss the PCRA petition pursuant to Pa.R.Crim.P. 

909(B)(2)(a), without holding an evidentiary hearing.

16

 On June 18, 2002, the PCRA court 

issued an order formally dismissing the petition. Cox appealed directly to this Court.17 In 

a divided opinion, we affirmed the order dismissing Cox’s petition without an evidentiary 

hearing.18

On February 17, 2005, Cox filed a second PCRA petition seeking an order vacating 

his death sentence pursuant to Atkins. Although the petition appeared to be facially 

untimely,19 the PCRA court found that Cox had established jurisdiction by satisfying the 

 

16 At the time, the PCRA court issued its notice of intent to dismiss pursuant to 

Pa.R.Crim.P. 1507. Our Rules of Criminal Procedure since have been renumbered, and 

Rule 1507 became Rule 907, which governs non-capital cases. For death penalty cases, 

Rule 909 is the applicable provision. See Pa.R.Crim.P. 909 (setting forth the “Procedures 

for Petitions in Death Penalty Cases”).

17 See 42 Pa.C.S. § 9546(d) (“A final court order under [the PCRA] in a case in which 

the death penalty has been imposed shall be directly appealable only to the Supreme 

Court pursuant to its rules.”).

18 See Cox II, 863 A.2d at 555. Chief Justice Castille and Justice Baer each filed 

concurring opinions. See id. at 555-57 (Castille, C.J., concurring); id. at 557-58 (Baer, J., 

concurring). Then-Justice, now Chief Justice, Saylor issued a dissenting opinion, id at 

558-62 (Saylor, J., dissenting), which was joined in part by Justice Nigro. See id. at 558 

(Nigro, J., dissenting).

19 See 42 Pa.C.S. § 9545(b)(1) (“Any petition under this subchapter, including a 

second or subsequent petition, shall be filed within one year of the date the judgment 

becomes final . . . .”).
[J-41-2020] - 15

newly-recognized, and retroactively applied,20 constitutional right exception to the 

PCRA’s time-bar, and by filing the petition within the applicable time frame. See Cox III, 

204 A.3d at 375.21 However, upon review of the merits of the petition, the PCRA court 

deemed Cox’s Atkins claim to amount to nothing more than a bald claim for relief, as Cox 

had failed “to include any certification or offer of proof in support of” his assertion that he 

was intellectually disabled. Id. at 375. Accordingly, the court dismissed the petition

without a hearing.

Cox appealed. In its Pa.R.A.P. 1925(a) opinion, the PCRA court recognized that 

its dismissal order was issued before this Court’s intervening decision in Miller, 888 A.2d 

at 624, which outlined how Atkins should be implemented in this Commonwealth. The 

PCRA court expressed its amenability to a remand in order to allow the parties to 

reconfigure their arguments, and to establish an evidentiary record if necessary, to 

conform to Miller. Cox then filed a petition with this Court seeking a remand for a hearing. 

On July 7, 2006, by per curiam order, we returned the case to the PCRA court for 

supplemental proceedings. See Cox III, 204 A.3d at 375.

 

20 As a general rule, the announcement of a new constitutional right does not 

automatically apply retroactively to cases that have become final. However, this rule is 

subject to an exception that encompasses cases in which the newly announced rule 

prohibits “a certain category of punishment for a class of defendants because of their 

status or offense.” Penry, 492 U.S. at 330. This carve-out from the general rule applies 

by its terms to Atkins’ core holding, and thus permits Atkins to serve as the basis for 42 

Pa.C.S. § 9545(b)(1)(iii).

21 Cox was required to file the petition invoking 42 Pa.C.S. § 9545(b)(1)(iii) within 

sixty days of the date on which the claim first became available to him. As we explained 

in Cox III, because Atkins was decided while Cox’s first PCRA petition and appeal were 

being litigated, he could not invoke the Supreme Court’s ruling until his first petition was 

decided with finality. Cox III, 204 A.3d at 375. We affirmed the order denying Cox’s first 

petition on December 22, 2004, and Cox filed his Atkins-related second PCRA petition 

within sixty days of that date, on February 17, 2005. Thus, the PCRA court correctly 

determined that Cox’s second petition was timely under 42 Pa.C.S. § 9545(b)(2).
[J-41-2020] - 16

Over the course of the next six years, the PCRA court conducted a number of 

evidentiary hearings at which “[m]ultiple witnesses testified, including three experts on 

behalf of [Cox], and two experts on behalf of the Commonwealth.” Id. In Cox III, we 

summarized the evidence presented at those hearings as follows:

[Cox] presented the testimony of various lay witnesses9 about their 

recollections of [Cox’s] chaotic upbringing, his abilities in performing tasks, 

following directions, interacting with peers, and other anecdotal information 

about [Cox] throughout the years. Dolores Jones, [Cox’s] mother, testified 

that [Cox] was the oldest of her [ten] children, and that she was [seventeen] 

years old at the time of his birth. Jones drank regularly during her 

pregnancy. The year after [Cox’s] birth, Jones married William Jones, with 

whom she had three more children in as many years. In 1972, Jones 

stabbed and killed William Jones. The children were in the home at the 

time. Jones was convicted of voluntary manslaughter and was sentenced 

to [twelve] years’ probation. By 1980, Jones had six more children with two 

different men. At some point, [Cox] went to live primarily with his paternal 

grandmother.

9 These witnesses included, Dolores Jones, [Cox’s] mother; 

Leslie Murphy, the mother of [Cox’s] three children; Kevin 

Moore, [Cox’s] cousin; Linston Cox, [Cox’s] uncle; Julius 

Moore, [Cox’s] uncle; Tameka Stevens, [Cox’s] childhood 

friend; and Lawrence, Tanya, and James Jones, [Cox’s] halfsiblings.

In general, the family witnesses described [Cox] as slow relative to children 

of his age. Peers picked on and bullied him for being slow. [Cox] did not 

comprehend his schoolwork and had his homework done for him. [Cox] 

could only tell time from a digital display. [Cox] was largely a follower, 

particularly in his relationship with [Lee,] the co-defendant. He generally 

associated with younger children. [Cox] needed prompting to maintain 

personal hygiene. [Cox] could not read well. Adults avoided sending him 

on errands that required reading or making change, which he was unable 

to perform.

Otis Peterkin, a fellow inmate at State Correctional Institutes at Huntington, 

Pittsburgh, and Greene, testified about [Cox’s] limited ability to read or write, 

and about his assistance to [Cox] in drafting and reading legal 

correspondence and grievances. He testified about his efforts to teach 

[Cox] to copy and write the alphabet and then copy sentences, so some of 

the documents could appear in [Cox’s] handwriting. Peterkin also 

connected [Cox] with another inmate, who had just passed his GED exam, 

to help him with his educational aspirations.
[J-41-2020] - 17

The Honorable William Meehan, Jr., who was [Cox’s] trial counsel before 

his eventual ascension to the bench of the Court of Common Pleas, 

testified. He related that after he represented [Cox] for a time and his 

contact with [Cox] was more frequent and prolonged, he discerned that 

[Cox’s] passive, mild, and cooperative manner masked a lack of 

comprehension of the proceedings and various aspects of the trial and 

defense. Attorney Meehan was also concerned given the academic records 

he reviewed. [Cox] repeated the first grade, and twice failed the seventh 

grade before dropping out of school. Accordingly, Attorney Meehan, with 

leave of court, arranged for an evaluation of [Cox’s] intellectual functioning, 

the results of which formed the basis for a midtrial suppression motion, and 

for mitigation during the penalty phase of the trial. Attorney Meehan 

engaged the services of [Dr.] Mark Molyneaux10, who administered a 

Weschler [sic] Adult Intelligence Scale[22] Revised (“WAIS-R”) test, which 

yielded an overall score of 69.

10 Dr. Molyneaux, a psychologist, had a master’s degree at 

the time he was retained, earning his doctorate sometime 

thereafter.

[Cox] offered the testimony of two expert witnesses in his initial 

presentation. Dr. Jethro Toomer, a clinical and forensic psychologist, 

explained that he was asked to offer an opinion regarding [Cox’s] adaptive 

functioning and the relation of any deficits to a diagnosis of intellectual 

disability. To do so, he reviewed prior evaluations, court records, school 

records, Department of Correction (“DOC”) records, and family affidavits. 

Dr. Toomer also evaluated [Cox] using the Scales of Independent Behavior 

 

22 The WAIS test, originally developed in 1955, is a comprehensive diagnostic 

assessment used to measure a person’s intelligence and cognitive ability. The test has 

seen a number of revisions and versions over the years. The most recent version is the 

WAIS-IV, which was released in 2008. Scholars have described the WAIS-IV as follows:

The WAIS-IV [] is a standardized measure of intelligence composed of 10 

subtests that load onto four indices that comprise the Full Scale IQ: Verbal 

Comprehension, Perceptual Reasoning, Working Memory, and Processing 

Speed. These indices provide information regarding the cognitive abilities 

of the participant in comparison to their relevant age group. The WAIS-IV 

has high validity and reliability with reliability coefficients greater than .90 on 

each subtest []. The WAIS-IV has a high correlation with the Stanford-Binet 

IV test (0.88), and other measures of the same nature. Although the WAISIV was normed on the general population, the standardization sample also 

included individuals diagnosed with intellectual disability.

Sydnee L. Erickson, Karen L. Salekin, Lauren N. Johnson & Stephanie C. Doran, The 

Predictive Power of Intelligence: Miranda Abilities of Individuals with Intellectual Disability, 

44 LAW & HUM. BEHAV. 60, 63 (2020).
[J-41-2020] - 18

Revised (“SIB-R”). He performed the SIB-R with [Cox], [Cox’s] mother, and 

[Cox’s] grandmother. Dr. Toomer explained that the SIB-R is an accepted 

tool to evaluate adaptive functioning. Its categories correspond to the 

social, conceptual, and practical skill areas identified [by the AAIDD] and 

similar designations in the DSM-IV. The SIB-R provides a global 

assessment appropriate for diagnostic purposes, where other tools may 

have a different focus, such as treatment, or programming. The 

assessment was administered in long form individually with [Cox’s] mother 

and grandmother because they were in a position to observe [Cox] at the 

respective ages he was while he resided with each of them. The measure 

of adaptive functioning is made relative to the overall community, not an 

isolated controlled environment, such as prison. The short form test 

administered to [Cox] reflected a broad age equivalent independent 

functioning of nine years and two months. To meet the definition of 

intellectual disability, deficits in at least two areas identified in the DSM-IV 

are required. Dr. Toomer testified [that] his evaluation revealed deficits in 

[fourteen] areas. Dr. Toomer noted that school records, which showed 

problems with attentiveness, focus, achievement, and personal 

relationships, confirmed his findings. Dr. Toomer also found the records of 

the DOC to be corroborative, including an entry by Dr. Dorothy Gold, a DOC 

managing psychologist, that [Cox] was “known to be mentally retarded.” 

From his assessment and the information reviewed, Dr. Toomer concluded, 

with a reasonable degree of professional certainty, that [Cox] had a lifelong 

history of impairment of adaptive functioning.

Dr. George McCloskey, psychologist and Director of Psychological 

Research at the Philadelphia College of Osteopathic Medicine, reviewed 

the various tests administered to [Cox] and the available records in order to 

form an opinion as to whether [Cox] met the definition for intellectual 

disability. He explained [that] the WAIS-R test performed by [Dr.] 

Molyneaux resulted in a verbal sub-score of 72 and a performance subscore of 68 for a composite score of 69. He noted [that Dr.] Molyneaux 

described the testing conditions in detail, expressing confidence in the 

validity of the test’s administration. The WAIS-R testing administered in 

Prison the following year consisted only of the verbal component and 

yielded a sub-score of 72, consistent with the earlier sub-score result. Dr. 

McCloskey also reviewed the result reached by a WAIS-III test administered 

by Dr. Stephen Berk in 2005. These tests have a SEM of plus or minus five 

points.

Dr. McCloskey explained that the tests are periodically revised and renormed to reflect currency with the knowledge and circumstances of the 

general public. The 1987 and 1988 tests used a version re-normed in 1978 

and the 2005 test employed a version re-normed in 1995.11 Dr. McCloskey 
[J-41-2020] - 19

cited studies discussing the “Flynn Effect”[23] which measures the overall 

drift of test scores in the population between each re-norming of the 

measuring tests. The WAIS-IV manual contains data for this effect between 

the -III and the current -IV versions reflecting an increase of about .3 point 

per year. Although acknowledging that it is not always applied, Dr. 

McCloskey opined that [the] best practice would be to account for this effect 

with a downward adjustment of the scores, which in the three subject tests 

would mean a three point downward adjustment.

11 The 1978 re-norming resulted in version II of the test later 

revised as WAIS-R and the 1995 re-norming resulted in 

version III.

Dr. McCloskey also testified that the fact [that Cox] achieved his GED in 

prison did not disprove the diagnosis of intellectual disability. He explained 

that [Cox] only passed on his second try after [fourteen] years of preparation 

in a structured supportive setting. He opined that his review of the essay 

portion of [Cox’s] GED exam reflects a [fourth to fifth] grade level. He also 

noted that the areas of improvement in the 2005 IQ test coincided with areas 

relevant to his GED study. There was little or no improvement in conceptual 

relations, comprehension, social reasoning, or understanding 

communication. Dr. McCloskey opined that the failure of [Cox’s] schools to 

designate him as in need of special education did not negate a diagnosis of 

intellectual disability, hypothesizing a number of possible reasons. Dr. 

McCloskey also relied on the findings of Dr. Toomer and the DOC records 

to confirm his conclusions that [Cox] meets the definition for a diagnosis of 

intellectual disability.

The Commonwealth offered the testimony of Dr. Paul Spangler, a 

psychologist employed with the Philadelphia Department of Mental 

Retardation. Dr. Spangler disputed that IQ tests closer to the age of 

[eighteen] had greater significance than did ones performed more recently. 

He questioned whether the conditions present during [Dr.] Molyneaux’s 

testing might call into question the result. He noted [that] the test was 

performed at night in the midst of [Cox’s] trial. He further noted that [Cox] 

did not have his eyeglasses at the time so that he was described as having 

to squint. Dr. Spangler opined that this might have depressed the result. 

He also noted that the 1987 test omitted, without explanation, a “block 

design” segment. The comparable segment in the 2005 test showed a 

score in the normal range. He opined that the omission might also have 

skewed the final score. Dr. Spangler also stated that he would not adjust a 

test score based on the Flynn Effect, but would address it in the comments 

 

23 The DSM-IV identifies the Flynn Effect as one possible factor that may affect the 

validity of a particular IQ assessment score. The effect refers generally to the production 

of overly high IQ scores that result from comparing current test results to out of date 

norms. See Cox III, 204 A.3d at 385 (citing DSM-IV at 37).
[J-41-2020] - 20

if relevant to the age of the test used. Dr. Spangler also questioned Dr. 

Toomer’s result of the SIB-R. He explained that the computer tabulation 

assesses for current age, while Dr. Toomer geared the questioning to earlier 

ages. He stated [that] the SIB-R is not a developmental scale but a present 

assessment. Dr. Spangler also questioned the relevance of the school 

records in this case, which reflected [Cox’s] extensive absences and his 

unstable home life that could account for his failure to achieve. Dr. Spangler 

also noted portions of the DOC records that reflected [Cox] with normal 

intelligence and adaptations, such as maintaining a job involving an 

[eighteen-step] protocol, and passing a GED exam. Dr. Spangler 

expressed an opinion that [Cox] is not intellectually disabled.

The Commonwealth also offered the testimony of Dr. Leigh Hagan, a clinical 

and forensic psychologist, to offer an opinion relative to methods and ethics. 

Dr. Hagan testified that it was not accepted practice to apply any correction 

for the Flynn Effect in scoring IQ tests. He noted [that] the goal is to use the 

most current version of the testing instrument and [to] restrict any 

consideration of the Flynn Effect to the comments. He noted [that] data 

showed the effect was neither constant nor predictable. He also testified 

that it is the general practice to rely on the most recent testing. He 

acknowledged that the WAIS-IV manual contains data for the Flynn Effect 

but has no instructions to adjust scoring.12

12 The Commonwealth also offered testimony and stipulations 

from DOC personnel attesting that the GED was appropriately 

administered and no special accommodation [was] requested.

In rebuttal, Dr. Kathleen Ross-Kidder, a clinical psychologist on the faculty 

of Georgetown and George Washington Universities, testified that the Flynn 

Effect is taught as part of the curriculum and that it would be reliable to use 

in scoring adjustment. She also met with [Cox] to achieve a general clinical 

impression through conversation and picture test cards used only as an 

assessment aid. Dr. Ross-Kidder testified that, based on data reflecting 

requests for special accommodation in taking the GED, which includes 

requests based on intellectual disability and attendant pass rates, it is 

probable that intellectually disabled individuals have passed the GED test. 

However, she could not cite a specific example. Dr. Ross-Kidder concluded 

that [Cox] possessed limited vocabulary, areas of interest, and perception, 

and that he displayed no indication of higher cognitive functioning.

Cox III, 204 A.3d at 378-82 (citations to notes of testimony omitted; minor punctuation

and capitalization modified for consistency).
[J-41-2020] - 21

Following the hearing, the PCRA court held that Cox had failed to carry his burden 

to prove that he was intellectually disabled.24 Relying largely upon credibility findings, the 

court ultimately determined that the testing protocol utilized by Drs. Molyneaux, Toomer, 

McCloskey, and Ross-Kidder did not yield a reliable assessment of Cox’s intellectual 

functioning. The court noted that the WAIS-R test likely was impacted, and thus produced

a lower and inaccurate result, because the test was performed at night, during the stress 

of Cox’s ongoing capital trial, and without the aid of Cox’s eyeglasses. The court also 

rejected Cox’s expert’s reliance upon three verbal subtests conducted by the DOC to 

adjust the score, in large part because the WAIS-R manual requires at least five subtests 

before prorating a result. Thus, no IQ determination based upon only three subtests could 

be deemed reliable.

The PCRA court found that a WAIS-III test conducted on Cox in 2005 (which at the 

time was the newest version of the test) produced the most reliable result. The test was 

administered using thirteen verbal subtests and using all but one of the performance 

subtests recommended by the manual. According to the PCRA court, the extent of testing 

in this instance required no substantive proration of the score, which, when adjusted for 

the five point SEM, produced an IQ score that did not point to intellectual disability. 

Further, the court rejected a deviation for the Flynn Effect, which it deemed not to be the 

standard practice among those in the field.

The PCRA court next determined that Cox had failed to prove that he suffered from 

significant deficits in adaptive functioning. The court relied substantially upon the fact that 

no school that Cox attended had identified him as a child with learning disabilities, 

 

24 Initially, the PCRA court did not explain its ruling in a written opinion. During his 

appeal to this Court, Cox filed ancillary motions bringing the absence of a written opinion 

to this Court’s attention. We directed the PCRA court to issue a written order and to clarify 

whether it intended to file a written opinion. See Cox III, 204 A.3d at 375. The court filed 

a written opinion on October 31, 2017. Id.
[J-41-2020] - 22

although systems were in place to allow such identification. Cox’s school records 

reflected numerous instances in which school officials contacted Cox’s family to discuss 

his poor attendance, need for eyeglasses, and various behavioral issues. Yet, the 

schools never observed deficiencies or disabilities significant enough to warrant placing 

Cox in special learning classes. The court concluded that Cox’s low academic 

performance was due to his consistent absences, rather than an intellectual disability. 

The PCRA court similarly deemed it significant that the DOC had evaluated Cox’s mental 

status between 2000 and 2003 and never found that Cox was intellectually disabled.

Next, the PCRA court discounted the testimony offered by the various members of 

Cox’s family, which the court dismissed as incredible and unreliable. The court also 

believed that Dr. Spangler, the Commonwealth’s expert, presented more expertise and 

objectivity than Dr. Toomer. In large part, this was because the PCRA court found Dr. 

Toomer’s methodology in applying the SIB-R testing to be suspect. Apparently, Dr. 

Toomer did not specify the source of his information, rendering it difficult at times to 

determine whether certain reports were provided by Cox, his mother, or his grandmother. 

Further, Dr. Toomer had failed to specify the time periods to which certain responses 

pertained. Thus, the court was unable to identify the point in Cox’s life during which he 

suffered from the difficulties identified by his mother and grandmother. The PCRA court 

also noted that Dr. Toomer’s opinion that Cox operated at the level of capability of a child 

with the approximate age of nine years and two months similarly was not placed on a 

chronological timeline. Dr. Toomer only stated that it was “prior to age” eighteen. The 

PCRA court also concluded that Dr. Toomer had failed to comply with the instructions 

provided in the manual for SIB-R testing by inappropriately using a score of zero or by 

leaving a score blank when the manual directed otherwise.
[J-41-2020] - 23

The PCRA court determined that Cox had not proven that the onset of any 

purported intellectual disability occurred before he reached the age of maturity. . In 

support of this finding, the PCRA court considered the Briseno factors.25 The court found 

the first factor—whether those who knew the person best considered the person to be 

intellectually disabled—to be most salient here. The court also deemed it important that 

Cox was able to earn his GED, a feat that the court believed rebutted any notion that Cox 

suffered from intellectual disability.

The PCRA court concluded that Cox had not proven, by a preponderance of the 

evidence, that he was intellectually disabled. Cox appealed to this Court.

C.

Upon review of the extensive evidence that was presented during the PCRA 

hearings, the PCRA court’s rationale, the parties’ arguments, and the present state of the 

governing law, see supra Section I, we uncovered “shortcomings” in the PCRA court’s 

analysis, and we found remand necessary. Cox III, 204 A.3d at 388.

Taken together, Atkins, Hall, Brumfield, and Moore compel courts evaluating 

claims of intellectual disability to recognize “the central role of the societal consensus to 

rely on medical and professional expertise in defining and diagnosing intellectual 

disability.” Id. at 387. In this line of cases, the Supreme Court consistently rebuffed

attempts by States to utilize arbitrary, political, or other extraneous considerations that 

departed from the mandate of relying upon medical and professional expertise. Id. at 

388. One such practice rejected by the High Court was consideration and application of 

the Briseno factors, a test that the Court perceived as elevating societal reaction and 

treatment over medical expertise and diagnosis. See Moore, 137 S.Ct. at 1051-53. 

Another approach that the High Court disfavored was an attempt by the state to allow 

 

25 See supra n.9.
[J-41-2020] - 24

courts to disregard the lower range of an IQ score (after being adjusted for the SEM)

when that range appeared facially to be inaccurate based upon other indicia presented 

with regard to the individual’s intellectual capabilities. Id. at 1049. The Court held that 

“the presence of other sources of imprecision in administering the test to a particular 

individual . . . cannot narrow the test-specific standard-error range.” Id. (emphasis in 

original).

Applying these guiding principles in Cox III, we concluded that the PCRA court 

made (at least) two consequential errors. First, the PCRA court “discounted the results 

of [a] 1987 WAIS-R test based on the possibility that testing conditions affected the result.” 

Cox III, 204 A.3d at 388. This aspect of the PCRA court’s analysis conflicted with the 

Moore Court’s directive that test-specific conditions that may result in imprecision cannot 

narrow the range within which a person can be considered intellectually disabled. Id. 

Second, in finding that the lay witness testimony presented on Cox’s behalf did not 

indicate a deficit in his adaptive behaviors, the PCRA court had relied specifically upon 

the Briseno factors. We noted that such reliance “clearly [is] erroneous in light of Moore.” 

Id. We continued: “[t]he ability of lay persons to recognize intellectual disability, let alone 

know what steps to take to secure a diagnosis for supportive services, is not a part of the 

professional diagnostic criteria that courts have been directed to employ.” Id.

These two “shortcomings” substantially undermined the PCRA court’s ultimate 

conclusion that Cox was not intellectually disabled. However, we also recognized that 

the court’s decision was multi-layered and dependent in large part upon credibility 

determinations that we, as an appellate court, are obliged to follow. Because those 

determinations could have been based upon “improper considerations,” we could not be 

confident that the PCRA court conducted a correct Atkins analysis. Id. at 388-89. We 
[J-41-2020] - 25

remanded the case to the PCRA court for reconsideration of its analysis “in light of the 

guidance provided by Hall, Brumfield, and Moore.” Id. at 389; see also id. at 392.26

D.

On remand, the PCRA court “reviewed the existing record in accordance with the 

Pennsylvania Supreme Court’s [order]” and again concluded that Cox “did not establish 

by a preponderance of the evidence that he is intellectually disabled.” PCRA Ct. Op., 

6/24/2019, at 1-2. The court explained:

Specifically, [Cox] did not present any probative evidence on the 

significance of any deficits in his adaptive functioning. [Cox’s] failure to 

introduce a single reliable clinical diagnosis of intellectual disability placing 

[Cox] at least two standard deviations below the mean in an adaptive skill 

set is antithetical to the principles clarified in Hall, Brumfield, and Moore[], 

and improperly invites this court to base an intellectual disability 

determination on evidence that is unpersuasive and outside the parameters 

of the medical community’s diagnostic framework.

Id. at 2 (emphasis in original).

After summarizing the testimony presented at the evidentiary hearings, the PCRA 

court reiterated the now well-established criteria for establishing that an individual suffers 

from intellectual disability, which in the context of the PCRA requires a petitioner to prove 

all of the following by a preponderance of the evidence: “(1) significant limitations in 

general intellectual functioning; (2) significant limitations in adaptive functioning; and (3) 

onset during the developmental period.” Id. at 19 (citation omitted).

The PCRA court noted that, although the Atkins Court passed the obligation of 

defining intellectual disability on to the States, the Court later imposed what the PCRA 

court characterized as “significant limitations” on the manner in which States are to 

 

26 Cox raised a litany of other issues, all of which the PCRA court had determined 

were untimely under the PCRA’s time limits. See 42 Pa.C.S. § 9545(b)(1). We agreed 

with the PCRA court’s jurisdictional determinations. Cox III, 204 A.3d at 389-92. Because 

those issues were not part of our remand, and have no bearing on our decision today, no 

further discussion of them is necessary here.
[J-41-2020] - 26

perform this task. Id. at 18. One such limitation is the requirement that intellectual 

disability determinations be “informed by the medical community’s diagnostic framework.” 

Id. (quoting Hall, 572 U.S. at 721). Such decisions cannot be “unfettered,” id., nor reliant 

only upon layperson testimony regarding personal experiences and observations of the 

individual at issue. The decisions must be guided by current medical standards. Moore, 

137 S.Ct. at 1053.

With these standards in mind, the PCRA court then analyzed the evidence 

presented at the hearings. Relying upon the DSM-5

27 and the applicable metric used by 

the AAIDD (approximately two standard deviations below the mean), the court determined

that Cox had proven by a preponderance of the evidence that he experienced significant 

deficits in intellectual functioning. PCRA Ct. Op., 6/24/2019, at 20. Cox underwent 

standardized IQ testing on a number of occasions. Those tests yielded an IQ score of 

69, which, after applying the SEM, fell within the relevant range for proving a deficit in 

intellectual functioning. The PCRA court found that the conclusion would be the same 

whether or not the Flynn Effect was applied, and, thus, did not resolve the question of 

whether applying the effect was standard medical practice. Id.

The PCRA court next assessed whether Cox had demonstrated significant deficits 

in adaptive functioning. Citing the standards outlined in the DSM-5 and the eleventh 

edition of the AAIDD manual, the court noted that, in order for a person to satisfy this 

criterion, he must prove that he has “a significant limitation” in one of three skill domains: 

conceptual, social, and practical skills. Id. at 21 (emphasis in original). Medical 

professionals make this assessment after “clinical evaluation in combination with a 

systematic review of existing records.” Id. The professional must evaluate and determine 

 

27 In 2013, the American Psychiatric Association published the fifth edition of the 

Diagnostic and Statistical Manual of Mental Disorders, the first to use an Arabic numeral 

in its title.
[J-41-2020] - 27

“whether an individual’s adaptive performance falls two or more standard deviations 

below the mean in any of the three adaptive skill sets.” Id. at 21-22 (quoting Moore, 137 

S.Ct. at 1046).

The court acknowledged the “substantial amount of anecdotal evidence” 

presented by Cox, but then emphasized that he had failed to “introduce any probative 

evidence that he has significant deficits in adaptive functioning.” Id. at 22 (emphasis in 

original). Specifically, the court found that Cox’s expert on this criterion, Dr. Toomer, did 

not credibly perform the applicable standardized testing, i.e., that he failed to comply with 

the instructions accompanying the standardized testing instruments used, rendering his 

opinion unworthy of evidentiary weight. Thus, “[w]ithout a reliable clinical assessment of 

[Cox’s] adaptive functioning, there is no preponderating evidence of [his] deficits in 

adaptive functioning placing [him] at [] least two standard deviations below the mean in 

at least one of the three adaptive skill domains.” Id. at 24. Consequently, Cox had not 

demonstrated that he was intellectually disabled so as to be entitled to Atkins relief.

III.

In his brief, Cox focuses his argument almost exclusively upon the PCRA court’s 

conclusion that Dr. Toomer’s assessment of Cox’s deficits in adaptive functioning was 

incredible and that it was the only probative evidence relevant to this criterion. Cox first 

asserts that the PCRA court confused “clinical assessment” with “standardized 

instrument.” Brief for Cox at 21. He adds that, while Pennsylvania favors the use of 

standardized testing in assessing this criterion, such testing is not required. Id. Indeed, 

even the DSM—unlike the AAIDD manual—mandates that a standardized instrument be 

used in making this determination. Cox points out that this Court has affirmed an 

intellectual disability finding where the record did not reflect the use of formalized testing. 

Id. at 22 (citing Commonwealth v. Keaton, 45 A.3d 1050, 1082 (Pa. 2012); Bracey, 1170 
[J-41-2020] - 28

A.3d at 284-86). He notes that, in Moore, the Supreme Court recognized the difference 

between the two, explaining that adaptive deficits must be “‘assessed using both clinical 

evaluation and individualized . . . measures.’” Id. (quoting Moore, 139 S.Ct. at 668).

Cox further relies upon the testimony of Dr. McCloskey, another of his experts,

who explained during the PCRA proceedings that, while standardized measures are the 

best option to assess one or more of the three adaptive skill domains, they are not always 

available. Id. at 22-23. Although standardized testing is necessary for purposes of 

evaluating and determining a person’s IQ score, Cox contends that such testing is neither 

required nor universally available for all that is encompassed within the deficit in adaptive 

skills criterion. Id. at 23. Cox highlights the AAIDD manuals and user’s guide, which he 

claims do not require only standardized testing, as they incorporate the potentiality of a 

decision based upon a clinical judgment in reliance upon multiple sources when 

standardized testing is not available. Id. at 23-24.

Thus, Cox argues, the PCRA court’s purported reliance upon standardized 

measures (and excluding consideration of all other evidence) as a prerequisite for 

establishing the adaptive skills criterion was misplaced. Id. at 25. Cox asserts that, under 

governing medical norms, and as found by other courts, “adaptive deficits can be 

assessed even when a standardized measure cannot be used.” Id. (citing United States 

v. Salad, 959 F. Supp. 2d 865, 878 (E.D. Va. 2013)). When the record is viewed in this

holistic light, Cox maintains, it is clear that he proved by a preponderance of the evidence 

that he had significant deficits in adaptive functioning for purposes of intellectual disability. 

He contends that the PCRA court’s creation of an erroneous threshold requirement 

caused that court to ignore a “wealth” of evidence that included testimony from lay 

witnesses, records, and expert clinical judgment. Id. at 26. Cox avers that, in declining 
[J-41-2020] - 29

to review and consider this evidence, the PCRA court made a judgment that fell outside 

medical community standards. Id. at 27.

Cox maintains that his experts, unlike the PCRA court, conformed to the prevailing 

medical standards and considered the totality of the evidence offered pertaining to Cox’s 

adaptive deficits, including voluminous records and lay witness observations. Id. at 29. 

Conversely, the PCRA court focused only upon Dr. Toomer and his supposed failure to 

observe the instructions for the tests that he used. At the same time, the court ignored 

the testimony from Dr. McCloskey, who “found that [] Cox had multiple deficits in adaptive 

functioning, specifically in areas of social skills; communication; self-care; self-direction; 

leisure; and work.” Id. (citing N.T. 11/9/2009, at 28-29). Dr. McCloskey also reviewed 

records pertaining to Cox and some of his family members, which Cox suggests “revealed 

a familial pattern of intellectual disability.” Id.

Next, Cox notes that Dr. Toomer similarly considered the “totality of the data” when 

rendering his clinical judgment regarding Cox’s adaptive deficits. Id. at 30 (quoting N.T. 

8/10/2009, at 38). In determining that Cox suffered from such deficits, Dr. Toomer not 

only performed the SIB-R testing on Cox and two members of his family, but also 

considered school and DOC records, lay witness observations and experiences with Cox, 

and Cox’s family history. Thus, even if a court ignored the SIB-R testing entirely, Cox 

contends, Dr. Toomer relied upon information sufficient to make a clinical diagnosis. Id.

After summarizing the evidence that he presented over the course of the PCRA 

proceedings, Cox urges this Court to find that the PCRA’s court’s determination that he 

failed to prove deficits in adaptive functioning was “contrary to controlling precedent, 

contrary to medical community standards, and directly disputed by the record evidence.” 

Id.at 44. For its part, the Commonwealth agrees that Cox is intellectually disabled, and 

that the PCRA court erred in finding otherwise. See Brief for the Commonwealth at 20, 
[J-41-2020] - 30

27. Like Cox, the Commonwealth urges this Court to vacate Cox’s death sentence, and 

to remand the case for resentencing. Id. at 28.

IV.

When evaluating the propriety of the denial of an Atkins-related claim, we apply 

the following standard of review:

A question involving whether a petitioner fits the definition of [intellectually

disabled] is fact intensive as it will primarily be based upon the testimony of 

experts and involve multiple credibility determinations. Accordingly, our 

standard of review is whether the factual findings are supported by 

substantial evidence and whether the legal conclusion drawn therefrom is 

clearly erroneous.

Commonwealth v. Hackett, 99 A.3d 11, 26 (Pa. 2014) (quoting Commonwealth v. 

Williams, 61 A.3d 979, 981 (Pa. 2013)).

As noted, for purposes of identifying the criteria for establishing intellectual 

disability, we declined in Miller to choose between the two preeminent medical sources,

as each considered the following three factors: (1) limited intellectual functioning; (2) 

significant adaptive limitations; and (3) onset before the age of maturity. Miller, 888 A.2d 

at 630. The first and third criteria are not contested in this appeal. Consequently, our 

present focus is upon the second criterion.

In Miller, we addressed how this criterion typically is understood and assessed:

Adaptive behavior is the collection of conceptual, social, and practical skills 

that have been learned by people in order to function in their everyday lives, 

and limitations on adaptive behavior are reflected by difficulties adjusting to 

ordinary demands made in daily life. The [AAIDD] recommends that such 

limitations should be established through the use of standardized 

measures. “On these standardized measures, significant limitations in 

adaptive behavior are operationally defined as performance that is at least 

two standard deviations below the mean of either (a) one of the following 

three types of adaptive behavior: conceptual, social, or practical, or (b) an 

overall score on a standardized measure of conceptual, social, and practical 

skills.”
[J-41-2020] - 31

Id. at 630-31 (citations and footnote omitted; emphasis added). In Commonwealth v. 

VanDivner, 178 A.3d 108 (Pa. 2018), we explained the three primary types of adaptive 

behavior in more detail:

Conceptual skills include language; reading and writing; and money, time, 

and number concepts. Practical skills relate to the activities of daily living, 

including personal care; occupational skills, health care; 

travel/transportation; schedules and routines; safety; use of money; and use 

of the telephone. Finally, social skills include interpersonal skills; social 

responsibility; self-esteem; gullibility; naiveté; social problem solving; the 

ability to follow rules and obey laws; and the ability to avoid being victimized.

Id. at 116 (citing INTELLECTUAL DISABILITY at 44; Miller, 888 A.2d at 630 n.8). In Williams, 

we emphasized that, in determining whether an individual has significant limitations in 

adaptive functioning:

the focus should be on an individual’s weaknesses—not his or her 

strengths—as [intellectually disabled] people can function in society and are 

able to obtain and hold low-skilled jobs, as well as have a family. This is 

represented in the DSM-IV and [AAIDD’s] definitions by an individual’s 

classification as [intellectually disabled] even though he may have relatively 

strong skills in distinct categories.

Williams, 61 A.3d at 992. The Supreme Court recently echoed this principle in Moore. 

See Moore, 137 S.Ct. at 1050.

Resolution of today’s appeal does not turn upon what it means to manifest

significant deficits in adaptive behavior. Instead, Cox’s dispute with the PCRA court’s 

ruling concerns the role that standardized measures and tests play in the assessment of 

the second Atkins criterion. In Miller, we reiterated that the AAIDD “recommends” that 

such measures be used to establish deficits in adaptive behavior (or lack thereof). Miller, 

888 A.2d at 630-31. The PCRA court apparently believed that this recommendation 

amounts to a consensus within the medical community. On the contrary, Cox argues,

standardized testing may be the preferred mechanism for evaluating a person’s adaptive 

behaviors, but it is not the only one.
[J-41-2020] - 32

The PCRA court found that Dr. Toomer’s administration of the SIB-R test to Cox, 

Cox’s mother, and Cox’s grandmother was “flawed,” and that Dr. Toomer’s evaluation of 

those results was “questionable” because his administration of the test “deviate[d] so far 

from the instruments’ guidelines that its results cannot be afforded any weight.” PCRA 

Ct. Op., 6/24/2019, at 22. Although the court acknowledged that intellectual disability is 

a “complex condition” and that clinicians must have some leeway in justifying their 

conclusions, id., it cautioned that, “under professional standards, it is essential that the 

clinician’s judgment rest on an empirical and fully documented assessment. When a 

clinician ignores basic scientific principles, the diagnoses lack validity.” Id. at 22-23.

The PCRA court first faulted Dr. Toomer for resting his conclusion upon the 

incorrect belief that Cox had spent the majority of his youth with his grandmother instead 

of his mother. In truth, Cox spent only a few years with his grandmother, whereas his 

mother had the ability and opportunity to observe him for at least fourteen years. 

Nonetheless, Dr. Toomer allowed Cox’s mother to limit her discussion of her observations 

of Cox’s behavior to the brief time period that Cox was a baby and lived with his 

grandmother. Dr. Toomer did not permit Cox’s mother to relate her experiences with Cox 

over the course of his entire adolescence. The PCRA court characterized this temporal 

limitation on her responses as “inexplicabl[e].” Id. at 23.

The court also criticized Dr. Toomer’s failure to follow the SIB-R’s instructions for 

increasing the reliability of the testing. For instance, Dr. Toomer failed to ask follow-up 

questions in order to resolve inconsistencies, “ignored noticeable inconsistent 

developmental patterns,” and failed to “ask the respondents to estimate [Cox’s] ability to 

perform tasks that [they] never observed [Cox] perform or tasks that [Cox] never had the 

opportunity to perform.” Id. (citations to notes of testimony omitted).
[J-41-2020] - 33

Combined, these two testing errors convinced the PCRA court that Dr. Toomer’s 

opinion merited no weight in the overall assessment of Cox’s intellectual ability. 

Apparently believing that a credible standardized measure was the only way to prove the 

second intellectual disability criterion, the PCRA court did not discuss or evaluate any 

other evidence of record. In that court’s view, once it determined that Dr. Toomer’s 

opinion on the test results was incredible, the analysis was over and there was nothing 

“probative” left to consider.28 We conclude that this was error.

To the extent that the PCRA court made a credibility determination with regard to 

Dr. Toomer’s test results, we will not disturb that finding, as it appears to be supported by 

the record. See Commonwealth v. Treiber, 121 A.3d 435, 444 (Pa. 2015) (“A PCRA 

court’s credibility findings are to be accorded great deference, and where supported by 

the record, such determinations are binding on a reviewing court.” (citation omitted)). Nor 

does Cox seriously contend that the PCRA court was not permitted to make such a 

finding. The crux of Cox’s argument is that, even if Dr. Toomer was incredible, the PCRA 

court was obliged to consider other evidence of record pertaining to the second criterion, 

as standardized measures are merely the preferred method of proof, not the exclusive 

one. See Brief for Cox at 21 (“Thus, while Pennsylvania favors the use of a standardized

instrument to assess adaptive deficits . . . , it does not require it.”). We agree.

As our intellectual disability jurisprudence has developed, we have come to rely

upon two primary medical sources to guide our understanding of, and decision making in, 

this complex area of law and science: the American Psychiatric Association’s DSM and 

the AAIDD’s definitions manual, INTELLECTUAL DISABILITY. See, e.g., Miller, 888 A.2d at 

629-31; Keaton, 45 A.3d at 1081; VanDivner, 178 A.2d at 115-16. The DSM does not 

mention standardized measures, let alone mandate such testing as the only means of 

 

28 See PCRA Ct. Op., 6/24/2019, at 22. 
[J-41-2020] - 34

proving the criterion. To the contrary, the DSM “requires significant limitations in at least 

two of the following skills: communication, self-care, home living, social/interpersonal 

skills, use of community resources, self-direction, functional academic skills, work, 

leisure, health, and safety.” Keaton, 45 A.3d at 1081 (citation omitted).

In turn, the AAIDD “recommends that such limitations should be established

through the use of standardized measures,” see Miller, 888 A.2d at 630-31 (citations and 

footnote omitted); Keaton, 45 A.3d at 1081, but does not mandate that such measures 

serve as the sole method for proving deficits in adaptive behaviors. Instead, the AAIDD 

demands “[a] comprehensive assessment of adaptive behavior” that may “include a 

systematic review of the individual’s family history, medical history, school records, 

employment records (if an adult), other relevant records and information, as well as 

clinical interviews with a person or persons who know the individual well.” See VanDivner, 

178 A.3d at 116 (quoting INTELLECTUAL DISABILITY at 45). In VanDivner, we explained that

“[i]deally, such information will be obtained from those who have had the opportunity to 

observe the person function across community settings and times. Very often, these 

people are parents, older siblings, other family members, teachers, employers, and 

friends.” VanDivner, 178 A.3d at 116 (cleaned up). Thus, while one of the two primary 

medical sources that we have used to guide our jurisprudence recommends standardized 

measures, neither one requires it. Nor has any Pennsylvania decision done so to this 

point.

The Supreme Court’s decision in Moore further validates our determination. In

Moore, the Court rejected the notion of tethering intellectual disability to arbitrary, political, 

or personal factors and disavowed adjudications that cast practices and opinions of the 

medical community to the wayside. The Court demanded just the opposite. Decisions 

pertaining to intellectual disability diagnoses and determinations must be based upon 
[J-41-2020] - 35

adaptive deficits, not strengths, and must conform with current standards recognized in 

the medical community. The Moore Court reaffirmed the principle enunciated in Hall and 

Brumfield that judicial decisions in this area must be “informed by the views of medical 

experts.” Moore, 137 S.Ct. at 1044 (quoting Hall, 572 U.S. at 721).

To say that courts must be “informed” by the experts in the field is not to say that 

courts must adhere “to everything stated in the latest medical guide.” Id. at 1049. Moore, 

the cases that preceded it, and our own precedents mandate only that decisions 

pertaining to intellectual disability respect the “central role of the societal consensus to 

rely on medical and professional expertise in defining and diagnosing intellectual 

disability.” Cox III, 204 A.3d at 387.

The current medical consensus does not command the introduction of 

standardized measures as a threshold obligation in order to establish intellectual 

disability. Such standard examinations are, of course, recommended, and are of great 

utility when properly administered. They are not, however, the exclusive means of 

proving adaptive deficiencies. Thus, while the PCRA court was entitled to find Dr. 

Toomer’s testing methods to be incredible and unworthy of evidentiary weight, that court

was not permitted to conclude its analysis upon reaching such a determination.

The record here is replete with other evidence germane to the evaluation of this 

criterion. Cox presented evidence from family members, friends, and prison inmates, all 

of whom similarly testified, inter alia, that Cox: (1) could not and did not read; (2) required 

assistance with hygiene; (3) did not perform well in school; (4) was unable to go to the 

store by himself and return with the correct items and change; (5) was picked on and 

bullied for his lack of intelligence; (6) could not care for younger siblings; (7) could not tell 

time using an analog clock; (8) tended to associate with people younger than him; (9) 

could not understand and follow rules of games; (10) was a follower and a pushover; (11) 
[J-41-2020] - 36

struggled to learn new skills or to comprehend basic math; (12) often was belittled as 

“retarded” by children in the neighborhood; (13) could not maintain employment; (14) 

could not cook for himself; and (15) could not fill out commissary slips, grievances, or 

legal paperwork in prison. Furthermore, Dr. McCloskey opined that Cox met the criteria 

for intellectual disability. Dr. McCloskey did not perform independent testing of Cox, but 

instead relied upon the records and testing performed by others. Nonetheless, Dr. 

McCloskey opined that Cox suffered multiple deficits in adaptive functioning, such as in 

social skills, communication, self-care, self-direction, leisure; and work. Cox also 

submitted records that document his behaviors in schools and in prison.

We recognize that, in its Pa.R.A.P. 1925(a) opinion in Cox III, the PCRA court 

found much of this evidence unreliable or incredible. Specifically, the court discredited 

the entirety of the lay witness testimony for purposes of the adaptive behavior inquiry, 

finding, inter alia: that these witnesses were biased because each had an interest in 

seeing Cox avoid execution; that there were inconsistences in their testimonies; that 

some had selective memories in a manner that benefitted Cox; and that many of their 

testimonies conflicted with Cox’s school records. See PCRA Ct. Op., 10/31/2017, at 33-

35. As well, the court found that the school records portrayed Cox in a much more 

functional light than did the evidence proffered by Cox at the PCRA hearings. Id. at 26-

31. When combined, these determinations, in addition to the court’s finding that Dr. 

Toomer’s testing was unreliable, led the PCRA court to conclude that Cox did not suffer 

from deficits in adaptive behaviors. To be sure, if the PCRA court again found that all of

the remaining evidence was incredible, the need for a remand now would be obviated. 

The difficulty is that our previous remand called the PCRA court’s prior credibility findings 

into question and directed that court to reconsider the testimony through the proper lens. 

It is not clear that the court did so.
[J-41-2020] - 37

In Cox III, we specifically acknowledged that, normally, we defer to the credibility 

findings of the fact-receiving courts. Cox III, 204 A.3d at 388. But we also explained that 

in this case those findings were based, “in part, on improper considerations.” Id. at 388-

89. Accordingly, we could not “conclude what credibility and factual determinations the 

PCRA court would have found, applying a correct Atkins analysis.” Id. at 389. In other 

words, we decided that the PCRA court’s reliance upon the Briseno factors called into 

question every aspect of the court’s decision, including its credibility determinations.

It is clear that, on remand, the PCRA court reconsidered some of its analysis, and 

altered its findings accordingly. For instance, the court reversed itself on the intellectual 

functioning prong. In its first opinion, the court found that Cox had not demonstrated an

IQ sufficiently low for Atkins purposes. See PCRA Ct. Op., 10/31/2017, at 11-16. In its 

second opinion, by contrast, the PCRA court found that Cox’s IQ score in fact 

demonstrated significant deficits in intellectual functioning. See PCRA Ct. Op., 

6/24/2019, at 20-21. However, it is not clear that the PCRA court reconsidered its other 

findings in a correct manner, as we required of it in Cox III. In its present analysis of the 

second criterion, the PCRA court focused entirely upon Dr. Toomer’s testing deficiencies, 

and effectively found that the entire prong rested upon the need for standardized testing. 

Within its discussion of that prong, the court made no mention, let alone any credibility 

findings, regarding the balance of the evidence. In view of our holding in Cox III that the 

prior determinations were questionable, we cannot now assume that the court made, or 

would have made, the same assessments about the veracity of that evidence.

Sprinkled throughout the PCRA court’s opinion are references to conflicts in 

testimony, or to inconsistencies that naturally would bear upon a court’s credibility 

findings. See e.g. PCRA Ct. Op., 6/24/2019, at 4 n.3-5; 15 n.14. And perhaps that court 

continues to believe that none of the twelve lay witnesses and none of the three expert 
[J-41-2020] - 38

witnesses testified about anything truthfully or reliably. If supported by the record, those 

mass credibility rulings at least would be entitled to presumptive deference from this 

Court. But that is not what the PCRA court determined in the analysis under challenge 

here. The court specifically found an absence of “probative” evidence regarding the 

“significance” of any deficits in Cox’s adaptive functioning. PCRA Ct. Op., 6/24/2019, at 

2. The court determined that Cox had failed to demonstrate such “significance” because 

he had “failed to introduce a single reliable clinical diagnosis,” a diagnosis the court 

apparently believed was required by Hall, Brumfield, and Moore. Id. But those cases did 

not announce such a requirement. The animating principle of those cases is the rule that 

prevailing medical methods and standards are not to be ignored in favor of arbitrary 

reliance upon non-medical observations and experiences. The High Court did not hold 

that a person can be deemed intellectually disabled only upon a clinical diagnosis, 

however preferable such a diagnosis may be. 

The PCRA court admitted that it did not consider any other evidence of record, 

regardless of any credibility determinations, because to do so would be “outside the 

parameters of the medical community’s diagnostic framework.” PCRA Ct. Op., 

6/24/2019, at 2. This was incorrect. While the medical community prefers clinical 

diagnoses, it does not require them. It is entirely reasonable to hypothesize a situation in 

which a person clearly is intellectually disabled, yet a clinical diagnosis based upon 

standardized testing models is impossible due to limited mental capacity or the death of 

essential witnesses. To allow execution of that person because of the inability to 

administer a standardize test runs afoul of the Eighth Amendment. Moreover, the medical 

community does not eschew consideration of lay witness input; it invites such input. The 

DSM requires consideration of “significant limitations” in “communication, self-care, home 

living, social/interpersonal skills, use of community resources, self-direction, functional 
[J-41-2020] - 39

academic skills, work, leisure, health, and safety.” Keaton, 45 A.3d at 1081 (citation 

omitted). And the AAIDD directs a “comprehensive assessment” of “the individual’s family 

history, medical history, school records, employment records (if an adult), other relevant 

records and information, as well as clinical interviews with a person or persons who know 

the individual well.” See VanDivner, 178 A.3d at 116 (quoting INTELLECTUAL DISABILITY at 

45). 

We take no position on whether the record evidence excluding Dr. Toomer’s 

conclusion demonstrates that Cox is, in fact, intellectually disabled, or whether that 

evidence even exemplifies deficits in adaptive behavior. We summarize this evidence 

merely to emphasize that the record contains information relevant to the adaptive 

behavior inquiry beyond that provided by Dr. Toomer’s standardized testing alone. The 

balance of evidence—when viewed as the medical community would—might bear upon 

the question of Cox’s ability to exhibit the three primary adaptive skills (conceptual, social, 

and practical) without significant deficits. The prevailing medical standard does not 

countenance a focus solely upon one standardized metric to the exclusion of everything 

else. 

In sum, the Eighth Amendment compels courts applying our definition of

intellectual disability to take into account, and to be guided by, current medical practices. 

The medical standards that we have adopted in Pennsylvania recommend the use of 

standardized measures, but do not mandate their use as the sole means to ascertain a 

person’s adaptive behaviors. Nor do current medical practices require clinicians or courts 

to ignore all other evidence when a standardized measure either is unavailable or 

incredible. The PCRA court operated under a contrary belief, and erroneously terminated 

its analysis prematurely upon determining that Dr. Toomer administered and evaluated

the standardized test improperly. The court found that, without credible standardized test 
[J-41-2020] - 40

results, it became effectively impossible for Cox to show that he suffered from significant 

deficits in adaptive behavior. Our law neither compels nor supports this truncated 

analysis. Consequently, we vacate the PCRA court’s order, and we remand for further 

consideration of Cox’s Atkins-based claim consistent with this opinion.

Justices Donohue and Mundy join the opinion.

Justice Dougherty files a concurring opinion in which Justice Mundy joins.

Chief Justice Saylor and Justices Baer and Todd did not participate in the 

consideration or decision of this case.