Hall v. Florida

(Slip Opinion) OCTOBER TERM, 2013 1

Syllabus

NOTE: Where it is feasible, a syllabus (headnote) will be released, as is

being done in connection with this case, at the time the opinion is issued.

The syllabus constitutes no part of the opinion of the Court but has been

prepared by the Reporter of Decisions for the convenience of the reader.

See United States v. Detroit Timber & Lumber Co., 200 U. S. 321, 337.

SUPREME COURT OF THE UNITED STATES

Syllabus

HALL v. FLORIDA

CERTIORARI TO THE SUPREME COURT OF FLORIDA

No. 12–10882. Argued March 3, 2014 —Decided May 27, 2014

After this Court held that the Eighth and Fourteenth Amendments

forbid the execution of persons with intellectual disability, see Atkins

v. Virginia, 536 U. S. 304, 321, Hall asked a Florida state court to va-

cate his sentence, presenting evidence that included an IQ test score

of 71. The court denied his motion, determining that a Florida stat-

ute mandated that he show an IQ score of 70 or below before being

permitted to present any additional intellectual disability evidence.

The State Supreme Court rejected Hall’s appeal, finding the State’s

70-point threshold constitutional.

Held: The State’s threshold requirement, as interpreted by the Florida

Supreme Court, is unconstitutional. Pp. 5–22.

(a) The Eighth Amendment, which “reaffirms the duty of the gov-

ernment to respect the dignity of all persons,” Roper v. Simmons, 543

U. S. 551, 560, prohibits the execution of persons with intellectual

disability. No legitimate penological purpose is served by executing

the intellectually disabled. Atkins, 563 U. S., at 317, 320. Prohibit-

ing such executions also protects the integrity of the trial process for

individuals who face “a special risk of wrongful execution” because

they are more likely to give false confessions, are often poor witness-

es, and are less able to give meaningful assistance to their counsel.

Id., at 320–321. In determining whether Florida’s intellectual disa-

bility definition implements these principles and Atkins’ holding, it is

proper to consider the psychiatric and professional studies that elab-

orate on the purpose and meaning of IQ scores and how the scores re-

late to Atkins, and to consider how the several States have imple-

mented Atkins. Pp. 5–7.

(b) Florida’s rule disregards established medical practice. On its

face, Florida’s statute could be consistent with the views of the medi-

cal community discussed in Atkins and with the conclusions reached

2 HALL v. FLORIDA

Syllabus

here. It defines intellectual disability as the existence of concurrent

deficits in intellectual and adaptive functioning, long the defining

characteristic of intellectual disability. See Atkins, supra, at 308.

And nothing in the statute precludes Florida from considering an IQ

test’s standard error of measurement (SEM), a statistical fact reflect-

ing the test’s inherent imprecision and acknowledging that an indi-

vidual score is best understood as a range, e.g., five points on either

side of the recorded score. As interpreted by the Florida Supreme

Court, however, Florida’s rule disregards established medical prac-

tice in two interrelated ways: It takes an IQ score as final and con-

clusive evidence of a defendant’s intellectual capacity, when experts

would consider other evidence; and it relies on a purportedly scien-

tific measurement of a defendant’s abilities, while refusing to recog-

nize that measurement’s inherent imprecision. While professionals

have long agreed that IQ test scores should be read as a range, Flori-

da uses the test score as a fixed number, thus barring further consid-

eration of other relevant evidence, e.g., deficits in adaptive function-

ing, including evidence of past performance, environment, and

upbringing. Pp. 7–12.

(c) The rejection of a strict 70-point cutoff in the vast majority of

States and a “consistency in the trend,” Roper, supra, at 567, toward

recognizing the SEM provide strong evidence of consensus that socie-

ty does not regard this strict cutoff as proper or humane. At most,

nine States mandate a strict IQ score cutoff at 70. Thus, in 41

States, an individual in Hall’s position would not be deemed automat-

ically eligible for the death penalty. The direction of change has been

consistent. Since Atkins, many States have passed legislation to

comply with the constitutional requirement that persons with intel-

lectual disability not be executed. Two of those States appear to set a

strict cutoff at 70, but at least 11 others have either abolished the

death penalty or passed legislation allowing defendants to present

additional intellectual disability evidence when their IQ score is

above 70. Every state legislature, save one, to have considered the

issue after Atkins and whose law has been interpreted by its courts

has taken a position contrary to Florida’s. Pp. 12–16.

(d) Atkins acknowledges the inherent error in IQ testing and pro-

vides substantial guidance on the definition of intellectual disability.

The States play a critical role in advancing the protections of Atkins

and providing this Court with an understanding of how intellectual

disability should be measured and assessed, but Atkins did not give

them unfettered discretion to define the full scope of the constitution-

al protection. Clinical definitions for intellectual disability which, by

their express terms, rejected a strict IQ test score cutoff at 70, and

which have long included the SEM, were a fundamental premise of

Cite as: 572 U. S. ____ (2014) 3

Syllabus

Atkins. See 536 U. S., at 309, nn. 3, 5. A fleeting mention of Florida

in a citation listing States that had outlawed the execution of the in-

tellectually disabled, id., at 315, did not signal the Atkins Court’s ap-

proval of the State’s current understanding of its law, which had not

yet been interpreted by the Florida Supreme Court to require a strict

70-point cutoff. Pp. 16–19.

(e) When a defendant’s IQ test score falls within the test’s

acknowledged and inherent margin of error, the defendant must be

able to present additional evidence of intellectual disability, including

testimony regarding adaptive deficits. This legal determination of in-

tellectual disability is distinct from a medical diagnosis but is in-

formed by the medical community’s diagnostic framework, which is of

particular help here, where no alternative intellectual disability defi-

nition is presented, and where this Court and the States have placed

substantial reliance on the medical profession’s expertise. Pp. 19–22.

109 So. 3d 704, reversed and remanded.

KENNEDY, J., delivered the opinion of the Court, in which GINSBURG,

BREYER, SOTOMAYOR, and KAGAN, JJ., joined. ALITO, J., filed a dissent-

ing opinion, in which ROBERTS, C. J., and SCALIA and THOMAS, JJ.,

joined.

Cite as: 572 U. S. ____ (2014) 1

Opinion of the Court

NOTICE: This opinion is subject to formal revision before publication in the

preliminary print of the United States Reports. Readers are requested to

notify the Reporter of Decisions, Supreme Court of the United States, Wash­

ington, D. C. 20543, of any typographical or other formal errors, in order

that corrections may be made before the preliminary print goes to press.

SUPREME COURT OF THE UNITED STATES

_________________

No. 12–10882

_________________

FREDDIE LEE HALL, PETITIONER v. FLORIDA

ON WRIT OF CERTIORARI TO THE SUPREME COURT OF

FLORIDA

[May 27, 2014]

JUSTICE KENNEDY delivered the opinion of the Court.

This Court has held that the Eighth and Fourteenth

Amendments to the Constitution forbid the execution of

persons with intellectual disability. Atkins v. Virginia,

536 U. S. 304, 321 (2002). Florida law defines intellectual

disability to require an IQ test score of 70 or less. If, from

test scores, a prisoner is deemed to have an IQ above 70,

all further exploration of intellectual disability is fore­

closed. This rigid rule, the Court now holds, creates an

unacceptable risk that persons with intellectual disability

will be executed, and thus is unconstitutional.

I

On February 21, 1978, Freddie Lee Hall, petitioner here,

and his accomplice, Mark Ruffin, kidnaped, beat, raped,

and murdered Karol Hurst, a pregnant, 21-year-old new­

lywed. Afterward, Hall and Ruffin drove to a convenience

store they planned to rob. In the parking lot of the store,

they killed Lonnie Coburn, a sheriff’s deputy who at­

tempted to apprehend them. Hall received the death

penalty for both murders, although his sentence for the

Coburn murder was later reduced on account of insuffi­

cient evidence of premeditation. Hall v. Florida, 403

2 HALL v. FLORIDA

Opinion of the Court

So. 2d 1319, 1321 (Fla. 1981) (per curiam).

Hall argues that he cannot be executed because of his

intellectual disability. Previous opinions of this Court

have employed the term “mental retardation.” This opin­

ion uses the term “intellectual disability” to describe the

identical phenomenon. See Rosa’s Law, 124 Stat. 2643

(changing entries in the U. S. Code from “mental retarda­

tion” to “intellectual disability”); Schalock et. al, The Re­

naming of Mental Retardation: Understanding the Change

to the Term Intellectual Disability, 45 Intellectual & De­

velopmental Disabilities 116 (2007). This change in ter­

minology is approved and used in the latest edition of the

Diagnostic and Statistical Manual of Mental Disorders,

one of the basic texts used by psychiatrists and other

experts; the manual is often referred to by its initials

“DSM,” followed by its edition number, e.g., “DSM–5.” See

American Psychiatric Association, Diagnostic and Statisti­

cal Manual of Mental Disorders 33 (5th ed. 2013).

When Hall was first sentenced, this Court had not yet

ruled that the Eighth Amendment prohibits States from

imposing the death penalty on persons with intellectual

disability. See Penry v. Lynaugh, 492 U. S. 302, 340

(1989). And at the time, Florida law did not consider

intellectual disability as a statutory mitigating factor.

After this Court held that capital defendants must be

permitted to present nonstatutory mitigating evidence in

death penalty proceedings, Hitchcock v. Dugger, 481 U. S.

393, 398–399 (1987), Hall was resentenced. Hall then

presented substantial and unchallenged evidence of intel­

lectual disability. School records indicated that his teach­

ers identified him on numerous occasions as “[m]entally

retarded.” App. 482–483. Hall had been prosecuted for a

different, earlier crime. His lawyer in that matter later

testified that the lawyer “[c]ouldn’t really understand

anything [Hall] said.” Id., at 480. And, with respect to the

murder trial given him in this case, Hall’s counsel recalled

Cite as: 572 U. S. ____ (2014) 3

Opinion of the Court

that Hall could not assist in his own defense because he

had “ ‘a mental . . . level much lower than his age,’ ” at best

comparable to the lawyer’s 4-year-old daughter. Brief for

Petitioner 11. A number of medical clinicians testified

that, in their professional opinion, Hall was “significantly

retarded,” App. 507; was “mentally retarded,” id., at 517;

and had levels of understanding “typically [seen] with

toddlers,” id., at 523.

As explained below in more detail, an individual’s abil­

ity or lack of ability to adapt or adjust to the requirements

of daily life, and success or lack of success in doing so, is

central to the framework followed by psychiatrists and

other professionals in diagnosing intellectual disability.

See DSM–5, at 37. Hall’s siblings testified that there was

something “very wrong” with him as a child. App. 466.

Hall was “slow with speech and . . . slow to learn.” Id., at

490. He “walked and talked long after his other brothers

and sisters,” id., at 461, and had “great difficulty forming

his words,” id., at 467.

Hall’s upbringing appeared to make his deficits in adap­

tive functioning all the more severe. Hall was raised—in

the words of the sentencing judge—“under the most horri­

ble family circumstances imaginable.” Id., at 53. Al­

though “[t]eachers and siblings alike immediately recog­

nized [Hall] to be significantly mentally retarded . . . [t]his

retardation did not garner any sympathy from his mother,

but rather caused much scorn to befall him.” Id., at 20.

Hall was “[c]onstantly beaten because he was ‘slow’ or

because he made simple mistakes.” Ibid. His mother

“would strap [Hall] to his bed at night, with a rope thrown

over a rafter. In the morning, she would awaken Hall by

hoisting him up and whipping him with a belt, rope, or

cord.” Ibid. Hall was beaten “ten or fifteen times a week

sometimes.” Id., at 477. His mother tied him “in a ‘croaker’

sack, swung it over a fire, and beat him,” “buried him

in the sand up to his neck to ‘strengthen his legs,’ ” and

4 HALL v. FLORIDA

Opinion of the Court

“held a gun on Hall . . . while she poked [him] with sticks.”

Hall v. Florida, 614 So. 2d 473, 480 (Fla. 1993) (Barkett,

C. J., dissenting).

The jury, notwithstanding this testimony, voted to

sentence Hall to death, and the sentencing court adopted

the jury’s recommendation. The court found that there

was “substantial evidence in the record” to support the

finding that “Freddie Lee Hall has been mentally retarded

his entire life.” App. 46. Yet the court also “suspect[ed]

that the defense experts [were] guilty of some professional

overkill,” because “[n]othing of which the experts testified

could explain how a psychotic, mentally-retarded, brain­

damaged, learning-disabled, speech-impaired person could

formulate a plan whereby a car was stolen and a conven­

ience store was robbed.” Id., at 42. The sentencing court

went on to state that, even assuming the expert testimony

to be accurate, “the learning disabilities, mental retarda­

tion, and other mental difficulties . . . cannot be used to

justify, excuse or extenuate the moral culpability of the

defendant in this cause.” Id., at 56. Hall was again sen­

tenced to death. The Florida Supreme Court affirmed,

concluding that “Hall’s argument that his mental retarda­

tion provided a pretense of moral or legal justification”

had “no merit.” Hall, 614 So. 2d, at 478. Chief Justice

Barkett dissented, arguing that executing a person with

intellectual disability violated the State Constitution’s

prohibition on cruel and unusual punishment. Id., at 481–

482.

In 2002, this Court ruled that the Eighth Amendment

prohibited the execution of persons with intellectual disa­

bility. Atkins v. Virginia, 536 U. S., at 321. On November

30, 2004, Hall filed a motion claiming that he had intellec­

tual disability and could not be executed. More than five

years later, Florida held a hearing to consider Hall’s mo­

tion. Hall again presented evidence of intellectual disabil­

ity, including an IQ test score of 71. (Hall had received

Cite as: 572 U. S. ____ (2014) 5

Opinion of the Court

nine IQ evaluations in 40 years, with scores ranging from

60 to 80, Brief for Respondent 8, but the sentencing court

excluded the two scores below 70 for evidentiary reasons,

leaving only scores between 71 and 80. See App. 107; 109

So. 3d 704, 707 (Fla. 2012)). In response, Florida argued

that Hall could not be found intellectually disabled be­

cause Florida law requires that, as a threshold matter,

Hall show an IQ test score of 70 or below before presenting

any additional evidence of his intellectual disability. App.

278–279 (“[U]nder the law, if an I. Q. is above 70, a person

is not mentally retarded”). The Florida Supreme Court

rejected Hall’s appeal and held that Florida’s 70-point

threshold was constitutional. 109 So. 3d, at 707–708.

This Court granted certiorari. 571 U. S. ___ (2013).

II

The Eighth Amendment provides that “[e]xcessive bail

shall not be required, nor excessive fines imposed, nor

cruel and unusual punishments inflicted.” The Four­

teenth Amendment applies those restrictions to the

States. Roper v. Simmons, 543 U. S. 551, 560 (2005);

Furman v. Georgia, 408 U. S. 238, 239–240 (1972) (per

curiam). “By protecting even those convicted of heinous

crimes, the Eighth Amendment reaffirms the duty of the

government to respect the dignity of all persons.” Roper,

supra, at 560; see also Trop v. Dulles, 356 U. S. 86, 100

(1958) (plurality opinion) (“The basic concept underlying

the Eighth Amendment is nothing less than the dignity of

man”).

The Eighth Amendment “is not fastened to the obsolete

but may acquire meaning as public opinion becomes en­

lightened by a humane justice.” Weems v. United States,

217 U. S. 349, 378 (1910). To enforce the Constitution’s

protection of human dignity, this Court looks to the “evolv­

ing standards of decency that mark the progress of a

maturing society.” Trop, supra, at 101. The Eighth

6 HALL v. FLORIDA

Opinion of the Court

Amendment’s protection of dignity reflects the Nation we

have been, the Nation we are, and the Nation we aspire to

be. This is to affirm that the Nation’s constant, unyielding

purpose must be to transmit the Constitution so that its

precepts and guarantees retain their meaning and force.

The Eighth Amendment prohibits certain punishments

as a categorical matter. No natural-born citizen may be

denaturalized. Ibid. No person may be sentenced to death

for a crime committed as a juvenile. Roper, supra, at 578.

And, as relevant for this case, persons with intellectual

disability may not be executed. Atkins, 536 U. S., at 321.

No legitimate penological purpose is served by executing

a person with intellectual disability. Id., at 317, 320. To

do so contravenes the Eighth Amendment, for to impose

the harshest of punishments on an intellectually disabled

person violates his or her inherent dignity as a human

being. “[P]unishment is justified under one or more of

three principal rationales: rehabilitation, deterrence, and

retribution.” Kennedy v. Louisiana, 554 U. S. 407, 420

(2008). Rehabilitation, it is evident, is not an applicable

rationale for the death penalty. See Gregg v. Georgia, 428

U. S. 153, 183 (1976) (joint opinion of Stewart, Powell, and

Stevens, JJ.). As for deterrence, those with intellectual

disability are, by reason of their condition, likely unable to

make the calculated judgments that are the premise for

the deterrence rationale. They have a “diminished ability”

to “process information, to learn from experience, to en­

gage in logical reasoning, or to control impulses . . .

[which] make[s] it less likely that they can process the

information of the possibility of execution as a penalty

and, as a result, control their conduct based upon that

information.” Atkins, 536 U. S., at 320. Retributive val­

ues are also ill-served by executing those with intellectual

disability. The diminished capacity of the intellectually

disabled lessens moral culpability and hence the retribu­

tive value of the punishment. See id., at 319 (“If the cul­

Cite as: 572 U. S. ____ (2014) 7

Opinion of the Court

pability of the average murderer is insufficient to justify

the most extreme sanction available to the State, the

lesser culpability of the mentally retarded offender surely

does not merit that form of retribution”).

A further reason for not imposing the death penalty on a

person who is intellectually disabled is to protect the

integrity of the trial process. These persons face “a special

risk of wrongful execution” because they are more likely to

give false confessions, are often poor witnesses, and are

less able to give meaningful assistance to their counsel.

Id., at 320–321. This is not to say that under current law

persons with intellectual disability who “meet the law’s

requirements for criminal responsibility” may not be tried

and punished. Id., at 306. They may not, however, re­

ceive the law’s most severe sentence. Id., at 318.

The question this case presents is how intellectual

disability must be defined in order to implement these

principles and the holding of Atkins. To determine if

Florida’s cutoff rule is valid, it is proper to consider the

psychiatric and professional studies that elaborate on the

purpose and meaning of IQ scores to determine how the

scores relate to the holding of Atkins. This in turn leads to

a better understanding of how the legislative policies of

various States, and the holdings of state courts, imple­

ment the Atkins rule. That understanding informs our

determination whether there is a consensus that instructs

how to decide the specific issue presented here. And, in

conclusion, this Court must express its own independent

determination reached in light of the instruction found in

those sources and authorities.

III

A

That this Court, state courts, and state legislatures

consult and are informed by the work of medical experts in

determining intellectual disability is unsurprising. Those

8 HALL v. FLORIDA

Opinion of the Court

professionals use their learning and skills to study and

consider the consequences of the classification schemes

they devise in the diagnosis of persons with mental or

psychiatric disorders or disabilities. Society relies upon

medical and professional expertise to define and explain

how to diagnose the mental condition at issue. And the

definition of intellectual disability by skilled professionals

has implications far beyond the confines of the death

penalty: for it is relevant to education, access to social

programs, and medical treatment plans. In determining

who qualifies as intellectually disabled, it is proper to

consult the medical community’s opinions.

As the Court noted in Atkins, the medical community

defines intellectual disability according to three criteria:

significantly subaverage intellectual functioning, deficits

in adaptive functioning (the inability to learn basic skills

and adjust behavior to changing circumstances), and onset

of these deficits during the developmental period. See id.,

at 308, n. 3; DSM–5, at 33; Brief for American Psychologi­

cal Association et al. as Amici Curiae 12–13 (hereinafter

APA Brief). This last factor, referred to as “age of onset,”

is not at issue.

The first and second criteria—deficits in intellectual

functioning and deficits in adaptive functioning—are

central here. In the context of a formal assessment, “[t]he

existence of concurrent deficits in intellectual and adap­

tive functioning has long been the defining characteristic

of intellectual disability.” Id., at 11.

On its face, the Florida statute could be consistent with

the views of the medical community noted and discussed

in Atkins. Florida’s statute defines intellectual disability

for purposes of an Atkins proceeding as “significantly

subaverage general intellectual functioning existing con­

currently with deficits in adaptive behavior and manifested

during the period from conception to age 18.” Fla. Stat.

§921.137(1) (2013). The statute further defines “signifi­

Cite as: 572 U. S. ____ (2014) 9

Opinion of the Court

cantly subaverage general intellectual functioning” as

“performance that is two or more standard deviations from

the mean score on a standardized intelligence test.” Ibid.

The mean IQ test score is 100. The concept of standard

deviation describes how scores are dispersed in a popula­

tion. Standard deviation is distinct from standard error of

measurement, a concept which describes the reliability of

a test and is discussed further below. The standard devia­

tion on an IQ test is approximately 15 points, and so two

standard deviations is approximately 30 points. Thus a

test taker who performs “two or more standard deviations

from the mean” will score approximately 30 points below

the mean on an IQ test, i.e., a score of approximately 70

points.

On its face this statute could be interpreted consistently

with Atkins and with the conclusions this Court reaches in

the instant case. Nothing in the statute precludes Florida

from taking into account the IQ test’s standard error of

measurement, and as discussed below there is evidence

that Florida’s Legislature intended to include the meas­

urement error in the calculation. But the Florida Su­

preme Court has interpreted the provisions more nar­

rowly. It has held that a person whose test score is above 70,

including a score within the margin for measurement

error, does not have an intellectual disability and is barred

from presenting other evidence that would show his facul­

ties are limited. See Cherry v. State, 959 So. 2d 702, 712–

713 (Fla. 2007) (per curiam). That strict IQ test score

cutoff of 70 is the issue in this case.

Pursuant to this mandatory cutoff, sentencing courts

cannot consider even substantial and weighty evidence of

intellectual disability as measured and made manifest by

the defendant’s failure or inability to adapt to his social

and cultural environment, including medical histories,

behavioral records, school tests and reports, and testimony

regarding past behavior and family circumstances. This is

10 HALL v. FLORIDA

Opinion of the Court

so even though the medical community accepts that all of

this evidence can be probative of intellectual disability,

including for individuals who have an IQ test score above

70. See APA Brief 15–16 (“[T]he relevant clinical authori­

ties all agree that an individual with an IQ score above 70

may properly be diagnosed with intellectual disability if

significant limitations in adaptive functioning also exist”);

DSM–5, at 37 (“[A] person with an IQ score above 70 may

have such severe adaptive behavior problems . . . that the

person’s actual functioning is comparable to that of indi­

viduals with a lower IQ score”).

Florida’s rule disregards established medical practice in

two interrelated ways. It takes an IQ score as final and

conclusive evidence of a defendant’s intellectual capacity,

when experts in the field would consider other evidence.

It also relies on a purportedly scientific measurement of

the defendant’s abilities, his IQ score, while refusing to

recognize that the score is, on its own terms, imprecise.

The professionals who design, administer, and interpret

IQ tests have agreed, for years now, that IQ test scores

should be read not as a single fixed number but as a

range. See D. Wechsler, The Measurement of Adult Intel­

ligence 133 (3d ed. 1944) (reporting the range of error on

an early IQ test). Each IQ test has a “standard error of

measurement,” ibid., often referred to by the abbreviation

“SEM.” A test’s SEM is a statistical fact, a reflection of

the inherent imprecision of the test itself. See R. Furr &

V. Bacharach, Psychometrics 118 (2d ed. 2014) (identify­

ing the SEM as “one of the most important concepts in

measurement theory”). An individual’s IQ test score on

any given exam may fluctuate for a variety of reasons.

These include the test-taker’s health; practice from earlier

tests; the environment or location of the test; the examin­

er’s demeanor; the subjective judgment involved in scoring

certain questions on the exam; and simple lucky guessing.

See American Association on Intellectual and Develop­

Cite as: 572 U. S. ____ (2014) 11

Opinion of the Court

mental Disabilities, R. Schalock et al., User’s Guide To

Accompany the 11th Edition of Intellectual Disability:

Definition, Classification, and Systems of Supports 22

(2012) (hereinafter AAIDD Manual); A. Kaufman, IQ

Testing 101, pp. 138–139 (2009).

The SEM reflects the reality that an individual’s intel­

lectual functioning cannot be reduced to a single numeri­

cal score. For purposes of most IQ tests, the SEM means

that an individual’s score is best understood as a range of

scores on either side of the recorded score. The SEM

allows clinicians to calculate a range within which one

may say an individual’s true IQ score lies. See APA Brief

23 (“SEM is a unit of measurement: 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 that the measured score is within a broader range”).

A score of 71, for instance, is generally considered to re­

flect a range between 66 and 76 with 95% confidence and a

range of 68.5 and 73.5 with a 68% confidence. See DSM–

5, at 37 (“Individuals with intellectual disability have

scores of approximately two standard deviations or more

below the population mean, including a margin for meas­

urement error (generally +5 points). . . . [T]his involves a

score of 65–75 (70 ± 5)”); APA Brief 23 (“For example, the

average SEM for the WAIS-IV is 2.16 IQ test points and

the average SEM for the Stanford-Binet 5 is 2.30 IQ test

points (test manuals report SEMs by different age group­

ings; these scores are similar, but not identical, often due

to sampling error)”). Even when a person has taken mul­

tiple tests, each separate score must be assessed using the

SEM, and the analysis of multiple IQ scores jointly is a

complicated endeavor. See Schneider, Principles of As­

sessment of Aptitude and Achievement, in The Oxford

Handbook of Child Psychological Assessment 286, 289–

291, 318 (D. Saklofske, C. Reynolds, V. Schwean, eds.

2013). In addition, because the test itself may be flawed,

12 HALL v. FLORIDA

Opinion of the Court

or administered in a consistently flawed manner, multiple

examinations may result in repeated similar scores, so

that even a consistent score is not conclusive evidence of

intellectual functioning.

Despite these professional explanations, Florida law

used the test score as a fixed number, thus barring further

consideration of other evidence bearing on the question of

intellectual disability. For professionals to diagnose—and

for the law then to determine—whether an intellectual

disability exists once the SEM applies and the individual’s

IQ score is 75 or below the inquiry would consider factors

indicating whether the person had deficits in adaptive

functioning. These include evidence of past performance,

environment, and upbringing.

B

A significant majority of States implement the protec­

tions of Atkins by taking the SEM into account, thus

acknowledging the error inherent in using a test score

without necessary adjustment. This calculation provides

“objective indicia of society’s standards” in the context of

the Eighth Amendment. Roper, 543 U. S., at 563. Only

the Kentucky and Virginia Legislatures have adopted a

fixed score cutoff identical to Florida’s. Ky. Rev. Stat.

Ann. §532.130(2) (Lexis Supp. 2013); Bowling v. Com-

monwealth, 163 S. W. 3d 361, 375 (Ky. 2005); Va. Code

Ann. §19.2–264.3:1.1 (Lexis Supp. 2013); Johnson v.

Commonwealth, 267 Va. 53, 75, 591 S. E. 2d 47, 59 (2004),

vacated and remanded on other grounds, 544 U. S. 901

(2005). Alabama also may use a strict IQ score cutoff at

70, although not as a result of legislative action. See

Smith v. State, 71 So. 3d 12, 20 (Ala. Crim. App. 2008)

(“The Alabama Supreme Court . . . did not adopt any

‘margin of error’ when examining a defendant’s IQ score”).

Petitioner does not question the rule in States which use a

bright-line cutoff at 75 or greater, Tr. of Oral Arg. 9, and

Cite as: 572 U. S. ____ (2014) 13

Opinion of the Court

so they are not included alongside Florida in this analysis.

In addition to these States, Arizona, Delaware, Kansas,

North Carolina, and Washington have statutes which

could be interpreted to provide a bright-line cutoff leading

to the same result that Florida mandates in its cases. See

Ariz. Rev. Stat. Ann. §13–753(F) (West 2013); Del. Code

Ann. Tit. 11, §4209(d)(3) (2012 Supp.); Kan. Stat. Ann.

§76–12b01 (2013 Supp.); N. C. Gen. Stat. Ann. §15A–2005

(Lexis 2013); Wash. Rev. Code §10.95.030(2)(c) (2012).

That these state laws might be interpreted to require a

bright-line cutoff does not mean that they will be so inter­

preted, however. See, e.g., State v. Vela, 279 Neb. 94, 126,

137, 777 N. W. 2d 266, 292, 299 (2010) (Although Nebras­

ka’s statute specifies “[a]n intelligence quotient of seventy

or below on a reliably administered intelligence quotient

test,” “[t]he district court found that [the defendant’s]

score of 75 on the [IQ test], considered in light of the

standard error of measurement, could be considered as

subaverage general intellectual functioning for purposes of

diagnosing mental retardation”).

Arizona’s statute appears to set a broad statutory cutoff

at 70, Ariz. Rev. Stat. Ann. §13–753(F) (West 2013), but

another provision instructs courts to “take into account

the margin of error for a test administered.” Id. at §14­

753(K)(5). How courts are meant to interpret the statute

in a situation like Hall’s is not altogether clear. The prin­

cipal Arizona case on the matter, State v. Roque, 141 P. 3d

368, (Ariz 2006), states that “the statute accounts for

margin of error by requiring multiple tests,” and that “if

the defendant achieves a full-scale score of 70 or below on

any one of the tests, then the court proceeds to a hearing.”

Id. at 403. But that case also notes that the defendant

had an IQ score of 80, well outside the margin of error,

and that all but one of the sub-parts of the IQ test were

“above 75.” Id.

Kansas has not had an execution in almost five decades,

14 HALL v. FLORIDA

Opinion of the Court

and so its laws and jurisprudence on this issue are unlikely

to receive attention on this specific question. See Atkins,

536 U. S., at 316 (“[E]ven in those States that allow the

execution of mentally retarded offenders, the practice

is uncommon. Some States . . . continue to authorize

executions, but none have been carried out in decades.

Thus there is little need to pursue legislation barring the

execution of the mentally retarded in those States”).

Delaware has executed three individuals in the past dec­

ade, while Washington has executed one person, and has

recently suspended its death penalty. None of the four

individuals executed recently in those States appears to

have brought a claim similar to that advanced here.

Thus, at most nine States mandate a strict IQ score

cutoff at 70. Of these, four States (Delaware, Kansas,

North Carolina, and Washington) appear not to have

considered the issue in their courts. On the other side of

the ledger stand the 18 States that have abolished the

death penalty, either in full or for new offenses, and Ore­

gon, which has suspended the death penalty and executed

only two individuals in the past 40 years. See Roper, 543

U. S., at 574 (“[The] Court should have considered those

States that had abandoned the death penalty altogether as

part of the consensus against the juvenile death penalty”).

In those States, of course, a person in Hall’s position

could not be executed even without a finding of intellectual

disability. Thus in 41 States an individual in Hall’s

position—an individual with an IQ score of 71—would not

be deemed automatically eligible for the death penalty.

These aggregate numbers are not the only considera­

tions bearing on a determination of consensus. Consistency

of the direction of change is also relevant. See id., at

565–566 (quoting Atkins, supra, at 315). Since Atkins,

many States have passed legislation to comply with the

constitutional requirement that persons with intellectual

disability not be executed. Two of these States, Virginia

Cite as: 572 U. S. ____ (2014) 15

Opinion of the Court

and Delaware, appear to set a strict cutoff at 70, although

as discussed, Delaware’s courts have yet to interpret the

law. In contrast, at least 11 States have either abolished

the death penalty or passed legislation allowing defend­

ants to present additional evidence of intellectual disabil­

ity when their IQ test score is above 70.

Since Atkins, five States have abolished the death pen­

alty through legislation. See 2012 Conn. Pub. Acts no. 12–

5; Ill. Comp. Stat. ch. 725, §119–1 (West 2012); Md. Cor­

rec. Servs. Code Ann. §3–901 et seq. (Lexis 2008); N. J.

Stat. Ann. §2C:11–3(b)(1) (West Supp. 2013); 2009 N. M.

Laws ch. 11, §§5–7. In addition, the New York Court of

Appeals invalidated New York’s death penalty under the

State Constitution in 2004, see People v. LeValle, 3 N. Y.

3d 88, 817 N. E. 2d 341 (2004), and legislation has not

been passed to reinstate it. And when it did impose the

death penalty, New York did not employ an IQ cutoff in

determining intellectual disability. N. Y. Crim. Proc. Law

Ann. §400.27(12)(e) (West 2005).

In addition to these States, at least five others have

passed legislation allowing a defendant to present addi­

tional evidence of intellectual disability even when an IQ

test score is above 70. See Cal. Penal Code Ann. §1376

(West Supp. 2014) (no IQ cutoff); Idaho Code §19–2515A

(Lexis Supp. 2013) (“seventy (70) or below”); Pizzutto v.

State, 146 Idaho 720, 729, 202 P. 3d 642, 651 (2008) (“The

alleged error in IQ testing is plus or minus five points.

The district court was entitled to draw reasonable infer­

ences from the undisputed facts”); La. Code Crim. Proc.

Ann., Art. 905.5.1 (West Supp. 2014) (no IQ cutoff); Nev.

Rev. Stat. §174.098.7 (2013) (no IQ cutoff); Utah Code Ann

§77–15a–102 (Lexis 2012) (no IQ cutoff). The U. S. Code

likewise does not set a strict IQ cutoff. See 18 U. S. C.

§3596(c). And no State that previously allowed defendants

with an IQ score over 70 to present additional evidence of

intellectual disability has modified its law to create a

16 HALL v. FLORIDA

Opinion of the Court

strict cutoff at 70. Cf. Roper, supra, at 566 (“Since Stan-

ford v. Kentucky, 492 U. S. 361 (1989), no State that previ­

ously prohibited capital punishment for juveniles has

reinstated it”).

In summary, every state legislature to have considered

the issue after Atkins—save Virginia’s—and whose law

has been interpreted by its courts has taken a position

contrary to that of Florida. Indeed, the Florida Legisla­

ture, which passed the relevant legislation prior to Atkins,

might well have believed that its law would not create

a fixed cutoff at 70. The staff analysis accompanying

the 2001 bill states that it “does not contain a set IQ

level . . . . Two standard deviations from these tests is ap­

proximately a 70 IQ, although it can be extended up to

75.” Fla. Senate Staff Analysis and Economic Impact

Statement, CS/SB 238, p. 11 (Feb. 14, 2001). But the

Florida Supreme Court interpreted the law to require a

bright-line cutoff at 70, see Cherry, 959 So. 2d, at 712–713,

and the Court is bound by that interpretation.

The rejection of the strict 70 cutoff in the vast majority

of States and the “consistency in the trend,” Roper, supra,

at 567, toward recognizing the SEM provide strong evi­

dence of consensus that our society does not regard this

strict cutoff as proper or humane.

C

Atkins itself acknowledges the inherent error in IQ

testing. It is true that Atkins “did not provide definitive

procedural or substantive guides for determining when a

person who claims mental retardation” falls within the

protection of the Eighth Amendment. Bobby v. Bies, 556

U. S. 825, 831 (2009). In Atkins, the Court stated:

“Not all people who claim to be mentally retarded will

be so impaired as to fall within the range of mentally

retarded offenders about whom there is a national

consensus. As was our approach in Ford v. Wain-

Cite as: 572 U. S. ____ (2014) 17

Opinion of the Court

wright with regard to insanity, ‘we leave to the

State[s] the task of developing appropriate ways to en­

force the constitutional restriction upon [their] execu­

tion of sentences.’ ” 536 U. S., at 317 (quoting Ford v.

Wainwright, 477 U. S. 399, 416–417 (1986); citation

omitted).

As discussed above, the States play a critical role in ad­

vancing protections and providing the Court with infor­

mation that contributes to an understanding of how intel­

lectual disability should be measured and assessed. But

Atkins did not give the States unfettered discretion to

define the full scope of the constitutional protection.

The Atkins Court twice cited definitions of intellectual

disability which, by their express terms, rejected a strict

IQ test score cutoff at 70. Atkins first cited the definition

provided in the DSM–IV: “ ‘Mild’ mental retardation is

typically used to describe people with an IQ level of 50–55

to approximately 70.” 536 U. S., at 308, n. 3 (citing Diag­

nostic and Statistical Manual of Mental Disorders 41 (4th

ed. 2000)). The Court later noted that “ ‘an IQ between 70

and 75 or lower . . . is typically considered the cutoff IQ

score for the intellectual function prong of the mental

retardation definition.’ ” 536 U. S., at 309, n. 5. Further­

more, immediately after the Court declared that it left “ ‘to

the States the task of developing appropriate ways to

enforce the constitutional restriction,’ ” id., at 317, the

Court stated in an accompanying footnote that “[t]he

[state] statutory definitions of mental retardation are not

identical, but generally conform to the clinical definitions,”

ibid.

Thus Atkins itself not only cited clinical definitions for

intellectual disability but also noted that the States’

standards, on which the Court based its own conclusion,

conformed to those definitions. In the words of Atkins,

those persons who meet the “clinical definitions” of intel­

18 HALL v. FLORIDA

Opinion of the Court

lectual disability “by definition . . . have diminished capac­

ities to understand and process information, to communi­

cate, to abstract from mistakes and learn from experience,

to engage in logical reasoning, to control impulses, and to

understand the reactions of others.” Id., at 318. Thus,

they bear “diminish[ed] . . . personal culpability.” Ibid.

The clinical definitions of intellectual disability, which

take into account that IQ scores represent a range, not a

fixed number, were a fundamental premise of Atkins. And

those clinical definitions have long included the SEM. See

Diagnostic and Statistical Manual of Mental Disorders 28

(rev. 3d ed. 1987) (“Since any measurement is fallible, an

IQ score is generally thought to involve an error of meas­

urement of approximately five points; hence, an IQ of 70 is

considered to represent a band or zone of 65 to 75. Treat­

ing the IQ with some flexibility permits inclusion in the

Mental Retardation category of people with IQs somewhat

higher than 70 who exhibit significant deficits in adaptive

behavior”).

Respondent argues that the current Florida law was

favorably cited by the Atkins Court. See Brief for Re­

spondent 18 (“As evidence of the national consensus, the

Court specifically cited Florida’s statute at issue here,

which has not substantively changed”). While Atkins did

refer to Florida’s law in a citation listing States which had

outlawed the execution of the intellectually disabled, 536

U. S., at 315, that fleeting mention did not signal the

Court’s approval of Florida’s current understanding of the

law. As discussed above, when Atkins was decided the

Florida Supreme Court had not yet interpreted the law to

require a strict IQ cutoff at 70. That new interpretation

runs counter to the clinical definition cited throughout

Atkins and to Florida’s own legislative report indicating

this kind of cutoff need not be used.

Respondent’s argument also conflicts with the logic of

Atkins and the Eighth Amendment. If the States were to

Cite as: 572 U. S. ____ (2014) 19

Opinion of the Court

have complete autonomy to define intellectual disability as

they wished, the Court’s decision in Atkins could become a

nullity, and the Eighth Amendment’s protection of human

dignity would not become a reality. This Court thus reads

Atkins to provide substantial guidance on the definition of

intellectual disability.

D

The actions of the States and the precedents of this

Court “give us essential instruction,” Roper, 543 U. S., at

564, but the inquiry must go further. “[T]he Constitution

contemplates that in the end our own judgment will be

brought to bear on the question of the acceptability of the

death penalty under the Eighth Amendment.” Coker v.

Georgia, 433 U. S. 584, 597 (1977) (plurality opinion).

That exercise of independent judgment is the Court’s

judicial duty. See Roper, supra, at 574 (“[T]o the extent

Stanford was based on a rejection of the idea that this

Court is required to bring its independent judgment to

bear on the proportionality of the death penalty for a

particular class of crimes or offenders, it suffices to note

that this rejection was inconsistent with prior Eighth

Amendment decisions” (citation omitted).

In this Court’s independent judgment, the Florida stat­

ute, as interpreted by its courts, is unconstitutional.

In addition to the views of the States and the Court’s

precedent, this determination is informed by the views of

medical experts. These views do not dictate the Court’s

decision, yet the Court does not disregard these informed

assessments. See Kansas v. Crane, 534 U. S. 407, 413

(2002) (“[T]he science of psychiatry . . . informs but does

not control ultimate legal determinations . . .”). It is the

Court’s duty to interpret the Constitution, but it need not

do so in isolation. The legal determination of intellectual

disability is distinct from a medical diagnosis, but it is

informed by the medical community’s diagnostic frame­

20 HALL v. FLORIDA

Opinion of the Court

work. Atkins itself points to the diagnostic criteria em­

ployed by psychiatric professionals. And the professional

community’s teachings are of particular help in this case,

where no alternative definition of intellectual disability is

presented and where this Court and the States have

placed substantial reliance on the expertise of the medical

profession.

By failing to take into account the SEM and setting a

strict cutoff at 70, Florida “goes against the unanimous

professional consensus.” APA Brief 15. Neither Florida

nor its amici point to a single medical professional who

supports this cutoff. The DSM–5 repudiates it: “IQ test

scores are approximations of conceptual functioning but

may be insufficient to assess reasoning in real-life situa­

tions and mastery of practical tasks.” DSM–5, at 37. This

statement well captures the Court’s independent assess­

ment that an individual with an IQ test score “between 70

and 75 or lower,” Atkins, supra, at 309, n. 5, may show

intellectual disability by presenting additional evidence

regarding difficulties in adaptive functioning.

The flaws in Florida’s law are the result of the inherent

error in IQ tests themselves. An IQ score is an approxi­

mation, not a final and infallible assessment of intellectual

functioning. See APA Brief 24 (“[I]t is standard pyscho­

metric practice to report the ‘estimates of relevant reliabil­

ities and standard errors of measurement’ when reporting

a test score”); ibid. (the margin of error is “inherent to the

accuracy of IQ scores”); Furr, Psychometrics, at 119

(“[T]he standard error of measurement is an important

psychometric value with implications for applied meas­

urement”). SEM is not a concept peculiar to the psychiat­

ric profession and IQ tests. It is a measure that is recog­

nized and relied upon by those who create and devise tests

of all sorts. Id., at 118 (identifying the SEM as “one of the

most important concepts in measurement theory”).

This awareness of the IQ test’s limits is of particular

Cite as: 572 U. S. ____ (2014) 21

Opinion of the Court

importance when conducting the conjunctive assessment

necessary to assess an individual’s intellectual ability.

See American Association on Intellectual and Develop­

mental Disabilities, Intellectual Disability: Definition,

Classification, and Systems of Supports 40 (11th ed. 2010)

(“It must be stressed that the diagnosis of [intellectual

disability] is intended to reflect a clinical judgment rather

than an actuarial determination”).

Intellectual disability is a condition, not a number. See

DSM–5, at 37. Courts must recognize, as does the medical

community, that the IQ test is imprecise. This is not to

say that an IQ test score is unhelpful. It is of considerable

significance, as the medical community recognizes. But in

using these scores to assess a defendant’s eligibility for the

death penalty, a State must afford these test scores the

same studied skepticism that those who design and use

the tests do, and understand that an IQ test score repre­

sents a range rather than a fixed number. A State that

ignores the inherent imprecision of these tests risks exe­

cuting a person who suffers from intellectual disability.

See APA Brief 17 (“Under the universally accepted clinical

standards for diagnosing intellectual disability, the court’s

determination that Mr. Hall is not intellectually disabled

cannot be considered valid”).

This Court agrees with the medical experts that when a

defendant’s IQ test score falls within the test’s acknowl­

edged and inherent margin of error, the defendant must

be able to present additional evidence of intellectual disa­

bility, including testimony regarding adaptive deficits.

It is not sound to view a single factor as dispositive of a

conjunctive and interrelated assessment. See DSM–5, at

37 (“[A] person with an IQ score above 70 may have such

severe adaptive behavior problems . . . that the person’s

actual functioning is comparable to that of individuals

with a lower IQ score”). The Florida statute, as interpreted

by its courts, misuses IQ score on its own terms; and

22 HALL v. FLORIDA

Opinion of the Court

this, in turn, bars consideration of evidence that must be

considered in determining whether a defendant in a capi­

tal case has intellectual disability. Florida’s rule is invalid

under the Constitution’s Cruel and Unusual Punishments

Clause.

E

Florida seeks to execute a man because he scored a 71

instead of 70 on an IQ test. Florida is one of just a few

States to have this rigid rule. Florida’s rule misconstrues

the Court’s statements in Atkins that intellectually dis­

ability is characterized by an IQ of “approximately 70.” 536

U. S., at 308, n. 3. Florida’s rule is in direct opposition to

the views of those who design, administer, and interpret

the IQ test. By failing to take into account the standard

error of measurement, Florida’s law not only contradicts

the test’s own design but also bars an essential part of a

sentencing court’s inquiry into adaptive functioning.

Freddie Lee Hall may or may not be intellectually dis­

abled, but the law requires that he have the opportunity to

present evidence of his intellectual disability, including

deficits in adaptive functioning over his lifetime.

The death penalty is the gravest sentence our society

may impose. Persons facing that most severe sanction

must have a fair opportunity to show that the Constitution

prohibits their execution. Florida’s law contravenes our

Nation’s commitment to dignity and its duty to teach

human decency as the mark of a civilized world. The

States are laboratories for experimentation, but those

experiments may not deny the basic dignity the Constitu­

tion protects.

The judgment of the Florida Supreme Court is reversed,

and the case is remanded for further proceedings not

inconsistent with this opinion.

So ordered.

Cite as: 572 U. S. ____ (2014) 1

ALITO, J., dissenting

SUPREME COURT OF THE UNITED STATES

_________________

No. 12–10882

_________________

FREDDIE LEE HALL, PETITIONER v. FLORIDA

ON WRIT OF CERTIORARI TO THE SUPREME COURT OF

FLORIDA

[May 27, 2014]

JUSTICE ALITO, with whom THE CHIEF JUSTICE, JUSTICE

SCALIA, and JUSTICE THOMAS join, dissenting.

In Atkins v. Virginia, 536 U. S. 304 (2002), the Court

held that the Eighth Amendment prohibits a death sen­

tence for defendants who are intellectually disabled but

does not mandate the use of a single method for identify­

ing such defendants. Today, the Court overrules the latter

holding based largely on the positions adopted by private

professional associations. In taking this step, the Court

sharply departs from the framework prescribed in prior

Eighth Amendment cases and adopts a uniform national

rule that is both conceptually unsound and likely to result

in confusion. I therefore respectfully dissent.

I

The Court’s approach in this case marks a new and most

unwise turn in our Eighth Amendment case law. In At-

kins and other cases, the Court held that the prohibition of

cruel and unusual punishment embodies the “evolving

standards of decency that mark the progress of a maturing

society,” and the Court explained that “those evolving

standards should be informed by objective factors to the

maximum possible extent.” Id., at 312 (internal quotation

marks omitted). In addition, the Court “pinpointed that

the clearest and most reliable objective evidence of con­

temporary values is the legislation enacted by the coun­

2 HALL v. FLORIDA

ALITO, J., dissenting

try’s legislatures.” Ibid.

In these prior cases, when the Court referred to the

evolving standards of a maturing “society,” the Court

meant the standards of American society as a whole. Now,

however, the Court strikes down a state law based on the

evolving standards of professional societies, most notably

the American Psychiatric Association (APA). The Court

begins its analysis with the views of those associations,

see ante, at 7–12, and then, after briefly discussing the

enactments of state legislatures, see ante, at 12–16, re­

turns to the associations’ views in interpreting Atkins and

in exercising the Court’s “independent judgment” on the

constitutionality of Florida’s law, see ante, at 16–22. This

approach cannot be reconciled with the framework pre­

scribed by our Eighth Amendment cases.

A

Under this Court’s modern Eighth Amendment prece­

dents, whether a punishment is “cruel and unusual” de­

pends on currently prevailing societal norms, and the

Court has long held that laws enacted by state legislatures

provide the “clearest and most reliable objective evidence

of contemporary values,” Penry v. Lynaugh, 492 U. S. 302,

331 (1989). This is so because “in a democratic society[,]

legislatures, not courts, are constituted to respond to the

will and consequently the moral values of the people,”

Gregg v. Georgia, 428 U. S. 153, 175–176 (1976) (joint

opinion of Stewart, Powell, and Stevens, JJ.) (internal

quotation marks omitted). Under this approach, as origi­

nally conceived, the Court first asked whether a chal­

lenged practice contravened a clear national consensus

evidenced by state legislation, and only if such a consen­

sus was found would the Court go on and ask “whether

there is reason to disagree with [the States’] judgment.”

Atkins, 536 U. S., at 313.

Invoking this two-step procedure, Atkins held that the

Cite as: 572 U. S. ____ (2014) 3

ALITO, J., dissenting

Eighth Amendment forbids the execution of defendants

who are intellectually disabled. See id., at 315–316.

Critical to the Court’s analysis was the conclusion that

“today our society views mentally retarded offenders as

categorically less culpable than the average criminal.” Id.,

at 316. “This consensus,” the Court continued, “unques­

tionably reflects widespread judgment about . . . the rela­

tionship between mental retardation and the penological

purposes served by the death penalty.” Id., at 317.

While Atkins identified a consensus against the execu­

tion of the intellectually disabled, the Court observed that

there was “serious disagreement” among the States with

respect to the best method for “determining which offend­

ers are in fact retarded.” Ibid. The Court therefore “le[ft]

to the States the task of developing appropriate ways” to

identify these defendants. Ibid. (internal quotation marks

and alteration omitted). As we noted just five years ago,

Atkins “did not provide definitive procedural or substan­

tive guides for determining when a person” is intellectually

disabled. Bobby v. Bies, 556 U. S. 825, 831 (2009).

B

Consistent with the role that Atkins left for the States,

Florida follows the procedure now at issue. As we ex­

plained in Atkins, in order for a defendant to qualify as

intellectually disabled, three separate requirements must

be met: It must be shown that a defendant has both

(1) significantly subaverage intellectual functioning and

(2) deficits in adaptive behavior, and that (3) the onset of

both factors occurred before the age of 18. See 536 U. S.,

at 318; ante, at 8. In implementing this framework, Flor­

ida has determined that the first requirement cannot be

satisfied if the defendant scores higher than 70 on IQ

tests, the long-accepted method of measuring intellectual

4 HALL v. FLORIDA

ALITO, J., dissenting

functioning.1 The Court today holds that this scheme

offends the Eighth Amendment. The Court objects that

Florida’s approach treats IQ test scores as conclusive and

ignores the fact that an IQ score might not reflect “true”

IQ because of errors in measurement. The Court then

concludes that a State must view a defendant’s IQ as a

range of potential scores calculated using a statistical

concept known as the “standard error of measurement” or

SEM. See Part II–B–1, infra. The Court holds that if this

range includes an IQ of 70 or below (the accepted level for

intellectual disability), the defendant must be permitted to

produce other evidence of intellectual disability in addition

to IQ scores.

I see no support for this holding in our traditional ap­

proach for identifying our society’s evolving standards of

decency. Under any fair analysis of current state laws,

the same absence of a consensus that this Court found in

Atkins persists today. It is telling that Hall himself does

not rely on a consensus among States. He candidly argues

instead that “the precise number of States that share

Florida’s approach is immaterial.” Reply Brief 2.

The Court’s analysis is more aggressive. According to

the Court, a “significant majority of States” reject Florida’s

“strict 70 cutoff ” and instead take “the SEM into account”

when deciding whether a defendant meets the first re­

quirement of the intellectual-disability test. Ante, at 12,

16. On the Court’s count, “at most nine States mandate a

strict IQ score cutoff at 70”; 22 States allow defendants to

present “additional evidence” when an individual’s test

——————

1 See, e.g., American Association of Intellectual and Developmental

Disabilities (AAIDD), Intellectual Disability 10–11 (11th ed. 2010)

(hereinafter AAIDD 11th ed.) (cataloguing history of IQ “cutoff criteria”

since 1959). Earlier publications of the AAIDD were published under

its former name, the American Association on Mental Retardation

(hereinafter AAMR).

Cite as: 572 U. S. ____ (2014) 5

ALITO, J., dissenting

score is between 70 and 75, ante, at 20;2 and 19 States

have abolished the death penalty or have long suspended

its operation. Ante, at 14. From these numbers, the Court

concludes that “in 41 States” a defendant “with an IQ

score of 71” would “not be deemed automatically eligible

for the death penalty.” Ibid.3 This analysis is deeply

flawed.

To begin, in addition to the 8 other States that the Court

recognizes as having rules similar to Florida’s, 1 more,

Idaho, does not appear to require courts to take the SEM

into account in rejecting a claim of intellectual disability.4

And of the remaining 21 States with the death penalty, 9

have either said nothing about the SEM or have not clari­

fied whether they require its use.5 Accordingly, of the

——————

2I assume that by “additional evidence” the Court means evidence

other than further IQ testing because Florida’s rule already “allows for

multiple evaluations, and . . . [petitioner] could have sought still more

testing.” Brief for Respondent 44. See also Brief for Petitioner 50; App.

107–108.

3 As I discuss below, the Florida Supreme Court did not base its deci­

sion on a finding that Hall’s IQ was 71. The Florida courts considered

several IQ scores, all above 70. See App. 107–108; Brief for Petitioner

50.

4 See Idaho Code §19–2515A(1)(b) (Lexis Cum. Supp. 2013); Pizzuto v.

State, 146 Idaho 720, 729, 202 P. 3d 642, 651 (2008) (stating that “the

legislature did not require that the IQ score be within five points of 70

or below” and giving the District Court discretion to interpret the

defendant’s IQ).

5 Montana, New Hampshire, and Wyoming have not ruled on the

subject. Two States have not defined “significantly subaverage” intel­

lectual functioning. See Colo. Rev. Stat. Ann. §18–1.3–1101(2) (2013);

S. C. Code Ann. §16–3–20 (2003 and 2013 Cum. Supp.); Franklin v.

Maynard, 356 S. C. 276, 278–279, 588 S. E. 2d 604, 605 (2003) (per

curiam). Two States have statutes that impose rebuttable presump­

tions of intellectual disability if a defendant’s IQ is below 65 or 70 but

have not said whether a defendant would be allowed to provide further

evidence if his IQ were over 70. See Ark. Code Ann. §5–4–618 (2013);

Neb. Rev. Stat. §28–105.01 (2013 Supp.). One State’s Supreme Court

mentioned measurement errors but only to explain why a defendant

6 HALL v. FLORIDA

ALITO, J., dissenting

death-penalty states, 10 (including Florida) do not require

that the SEM be taken into account, 12 consider the SEM,

and 9 have not taken a definitive position on this question.

These statistics cannot be regarded as establishing a

national consensus against Florida’s approach.

Attempting to circumvent these statistics, the Court

includes in its count the 19 States that never impose the

death penalty, but this maneuver cannot be justified. It is

true that the Court has counted non-death-penalty States

in some prior Eighth Amendment cases, but those cases

concerned the substantive question whether a class of

individuals should be categorically ineligible for the death

penalty. In Roper v. Simmons, 543 U. S. 551 (2005), for

example, the Court counted non-death-penalty States as

part of the consensus against the imposition of a capital

sentence for a crime committed by a minor. Id., at 574.

The Court reasoned that a State’s decision to abolish the

death penalty necessarily “demonstrates a judgment that

the death penalty is inappropriate for all offenders, includ­

ing juveniles.” Ibid.

No similar reasoning is possible here. The fact that a

State has abolished the death penalty says nothing about

how that State would resolve the evidentiary problem of

identifying defendants who are intellectually disabled. As

I explain below, a State may reasonably conclude that

Florida’s approach is fairer than and just as accurate as

the approach that the Court now requires, and therefore it

cannot be inferred that a non-death-penalty State, if

forced to choose between the two approaches, would neces­

sarily select the Court’s. For all these reasons, it is quite

——————

must prove deficits in adaptive behavior despite having an IQ below 70.

See Stripling v. State, 261 Ga. 1, 3, 401 S. E. 2d 500, 504 (1991).

Another State’s Supreme Court mentioned the SEM in responding to

an argument by the defendant, but it did not suggest that the SEM was

legally relevant. See Goodwin v. State, 191 S. W. 3d 20, 30–31, and n. 7

(Mo. 2006).

Cite as: 572 U. S. ____ (2014) 7

ALITO, J., dissenting

wrong for the Court to proclaim that “the vast majority of

States” have rejected Florida’s approach. Ante, at 16.

Not only are the States divided on the question whether

the SEM should play a role in determining whether a

capital defendant is intellectually disabled, but the States

that require consideration of the SEM do not agree on the

role that the SEM should play. Those States differ, for

example, on the sort of evidence that can be introduced

when IQ testing reveals an IQ over 70. Some require

further evidence of intellectual deficits, while others per­

mit the defendant to move on to the second prong of the

test and submit evidence of deficits in adaptive behavior.6

The fairest assessment of the current situation is that the

States have adopted a multitude of approaches to a very

difficult question.

In light of all this, the resolution of this case should be

straightforward: Just as there was no methodological

consensus among the States at the time of Atkins, there is

no such consensus today. And in the absence of such a

consensus, we have no basis for holding that Florida’s

method contravenes our society’s standards of decency.

C

Perhaps because it recognizes the weakness of its argu­

ments about a true national consensus, the Court places

heavy reliance on the views (some only recently an­

nounced) of professional organizations, but the Court

attempts to downplay the degree to which its decision is

dependent upon the views of these private groups. In a

game attempt to shoehorn the views of these associations

into the national-consensus calculus, the Court reasons as

follows. The views of these associations, the Court states,

help in determining “how [IQ] scores relate to the holding

——————

6 Compare Ybarra v. State, 127 Nev. ___, ___, 247 P. 3d 269, 274

(2011), with State v. Dunn, 2001–1635, pp. 25–26 (La. 5/11/10), 41 So.

3d 454, 470.

8 HALL v. FLORIDA

ALITO, J., dissenting

in Atkins”; “[t]his in turn leads to a better understanding

of how the legislative policies of various States, and the

holdings of state courts, implement the Atkins rule”; and

“[t]hat understanding informs our determination whether

there is a consensus that instructs how to decide the spe­

cific issue presented here.” Ante, at 7.

I cannot follow the Court’s logic. Under our modern

Eighth Amendment cases, what counts are our society’s

standards—which is to say, the standards of the American

people—not the standards of professional associations,

which at best represent the views of a small professional

elite.

The Court also mistakenly suggests that its methodol­

ogy is dictated by Atkins. See ante, at 16–19. On the con-

trary, Atkins expressly left “to the States” the task of

defining intellectual disability. And although the Atkins

Court perceived a “professional consensus” about the best

procedure to be used in identifying the intellectually dis­

abled, the Atkins Court declined to import that view into

the law. 536 U. S., at 316, n. 21. Instead, the Court made

clear that this professional consensus was “by no means

dispositive.” Id., at 317, n. 21; see id., at 317, and n. 22.

D

The Court’s reliance on the views of professional associ­

ations will also lead to serious practical problems. I will

briefly note a few.

First, because the views of professional associations

often change,7 tying Eighth Amendment law to these

views will lead to instability and continue to fuel pro­

tracted litigation. This danger is dramatically illustrated

by the most recent publication of the APA, on which the

Court relies. This publication fundamentally alters the

——————

7 See Forensic Psychology and Neuropsychology for Criminal and

Civil Cases 57 (H. Hall ed. 2008) (hereinafter Forensic Psychology).

Cite as: 572 U. S. ____ (2014) 9

ALITO, J., dissenting

first prong of the longstanding, two-pronged definition of

intellectual disability that was embraced by Atkins and

has been adopted by most States. In this new publication,

the APA discards “significantly subaverage intellectual

functioning” as an element of the intellectual-disability

test.8 Elevating the APA’s current views to constitutional

significance therefore throws into question the basic ap­

proach that Atkins approved and that most of the States

have followed.

It is also noteworthy that changes adopted by profes­

sional associations are sometimes rescinded. For example,

in 1992 the AAIDD extended the baseline “intellectual

functioning cutoff ” from an “IQ of 70 or below” to a “score

of approximately 70 to 75 or below.” AAIDD 11th ed. 10

(Table 1.3) (boldface deleted); see 2 Kaplan & Sadock’s

Comprehensive Textbook of Psychiatry 3449 (B. Sadock,

V. Sadock, & P. Ruiz eds., 9th ed. 2009) (hereinafter

Kaplan & Sadock’s). That change “generated much con­

troversy”; by 2000, “only 4 states used the 1992 AAIDD

definition, with 44 states continuing to use the 1983 defi­

nition.” Ibid. And in the 2002 AAIDD, the baseline “IQ

cut-off was changed” back to approximately “70 or less.”

Ibid.

Second, the Court’s approach implicitly calls upon the

Judiciary either to follow every new change in the think­

ing of these professional organizations or to judge the

validity of each new change. Here, for example, the Court

tacitly makes the judgment that the diagnostic criteria for

intellectual disability that prevailed at the time when

Atkins was decided are no longer legitimate. The publica­

tions that Atkins cited differ markedly from more recent

——————

8 Compare APA, Diagnostic and Statistical Manual of Mental Disor­

ders 39, 41, 42 (rev. 4th ed. 2000) (hereinafter DSM–IV–TR), with APA,

Diagnostic and Statistical Manual of Mental Disorders 33, 809 (5th

ed. 2013) (hereinafter DSM–5).

10 HALL v. FLORIDA

ALITO, J., dissenting

editions now endorsed by the Court. See 536 U. S., at 308,

n. 3.

Third, the Court’s approach requires the Judiciary to

determine which professional organizations are entitled to

special deference. And what if professional organizations

disagree? The Court provides no guidance for deciding

which organizations’ views should govern.

Fourth, the Court binds Eighth Amendment law to

definitions of intellectual disability that are promulgated

for use in making a variety of decisions that are quite

different from the decision whether the imposition of a

death sentence in a particular case would serve a valid

penological end. In a death-penalty case, intellectual

functioning is important because of its correlation with the

ability to understand the gravity of the crime and the

purpose of the penalty, as well as the ability to resist a

momentary impulse or the influence of others. See id., at

318, 320. By contrast, in determining eligibility for social

services, adaptive functioning may be much more im­

portant. Cf. DSM–IV–TR, at xxxvii (clinical “considera­

tions” may not be “relevant to legal judgments” that turn

on “individual responsibility”); DSM–5, at 20 (similar).

Practical problems like these call for legislative judg­

ments, not judicial resolution.

II

Because I find no consensus among the States, I would

not independently assess the method that Florida has

adopted for determining intellectual disability. But even

if it were appropriate for us to look beyond the evidence of

societal standards, I could not conclude that Florida’s

method is unconstitutional. The Court faults Florida for

“tak[ing] an IQ score as final and conclusive evidence of a

defendant’s intellectual capacity” and for failing to recog­

nize that an IQ score may be imprecise. Ante, at 10. In

my view, however, Florida has adopted a sensible stand­

Cite as: 572 U. S. ____ (2014) 11

ALITO, J., dissenting

ard that comports with the longstanding belief that IQ

tests are the best measure of intellectual functioning. And

although the Court entirely ignores this part of the Florida

scheme, the State takes into account the inevitable risk of

testing error by permitting defendants to introduce multi­

ple scores.

In contrast, the Court establishes a standard that

conflates what have long been understood to be two inde-

pendent requirements for proving intellectual disability:

(1) significantly subaverage intellectual functioning and

(2) deficits in adaptive behavior. The Court also mandates

use of an alternative method of dealing with the risk of

testing error without any hint that it is more accurate

than Florida’s approach.

A

1

The first supposed error that the Court identifies is that

Florida “takes an IQ score” as “conclusive evidence” of

intellectual functioning. Ante, at 10. As an initial matter,

one would get the impression from reading the Court’s

opinion that Hall introduced only one test score (of 71).

See ante, at 14. In truth, the Florida courts considered

multiple scores, all above 70, on the particular IQ test that

Hall has dubbed the “gold standard.” See Brief for Peti­

tioner 50; App. 107–108.9 Florida’s statute imposes no

limit on the number of IQ scores that a defendant may

introduce, so the Court is simply wrong to analyze the

Florida system as one that views a single IQ score above

70 as “final and conclusive evidence” that a defendant does

not suffer from subaverage intellectual functioning. See

——————

9 See Brief for Petitioner 50 (listing his valid IQ scores of 71, 72, 73,

and 80). Hall alleges that he also scored a 69 on a Wechsler test, but

that score was not admitted into evidence because of doubts about its

validity. App. 107. Hall does not allege that any potential “practice

effect” skewed his scores.

12 HALL v. FLORIDA

ALITO, J., dissenting

Brief for Respondent 44 (“Florida’s Rule allows for multi­

ple evaluations, and if Hall believed a statistical error rate

prevented any of his tests from reflecting his true score, he

could have sought still more testing”).

The proper question to ask, therefore, is whether Flor­

ida’s actual approach falls outside the range of discretion

allowed by Atkins. The Court offers no persuasive reason

for concluding that it does. Indeed, the Court’s opinion

never identifies what other evidence of intellectual func­

tioning it would require Florida to admit. As we recog­

nized in Atkins, the longstanding practices of the States,

and at least the previous views of professional organiza­

tions, seem to reflect the understanding that IQ scores are

the best way to measure intellectual functioning. See 536

U. S., at 316.10 Until its most recent publication, the APA,

for example, ranked the severity of intellectual disability

exclusively by IQ scores, necessarily pinpointing the onset

of the disability according to IQ. See DSM–IV–TR, at 42.

We have been presented with no solid evidence that the

longstanding reliance on multiple IQ test scores as a

measure of intellectual functioning is so unreasonable or

outside the ordinary as to be unconstitutional. The Court

has certainly not supplied any such information.

2

If the Court had merely held that Florida must permit

defendants to introduce additional evidence (whatever

that might be) of significantly subaverage intellectual

——————

10 See AAIDD 11th ed. 10 (cataloguing history of IQ “cutoff criteria”

since 1959); DSM–IV–TR, at 39 (“Mental Retardation” is “characterized

by significantly subaverage intellectual functioning (an IQ of approxi­

mately 70 or below) . . .” (boldface deleted)); id., at 41 (“General intellec­

tual functioning is defined by the intelligence quotient . . .” (italics

deleted)); AAMR, Mental Retardation 14 (10th ed. 2002) (hereinafter

AAMR 10th ed.) (“[I]ntellectual functioning is still best represented by

IQ scores . . .”).

Cite as: 572 U. S. ____ (2014) 13

ALITO, J., dissenting

functioning, its decision would be more limited in scope.

But as I understand the Court’s opinion, it also holds that

when IQ tests reveal an IQ between 71 and 75, defendants

must be allowed to present evidence of deficits in adaptive

behavior—that is, the second prong of the intellectual­

disability test. See ante, at 9–10, 12, 20. That is a re­

markable change in what we took to be a universal under­

standing of intellectual disability just 12 years ago.

In Atkins, we instructed that “clinical definitions of

mental retardation require not only [(1)] subaverage intel­

lectual functioning, but also [(2)] significant limitations in

adaptive skills.” 536 U. S., at 318 (emphasis and altera­

tions added). That is the approach taken by the vast

majority of States.11 As the Court correctly recognizes,

most States require “concurrent deficits” in intellectual

functioning and adaptive behavior, requiring defendants

to prove both. Ante, at 8 (emphasis added).12

Yet the Court now holds that when a defendant’s IQ

score is as high as 75, a court must “consider factors indi­

cating whether the person has deficits in adaptive func­

tioning.” Ante, at 12; see ante, at 9–10, 20. In other

words, even when a defendant has failed to show that he

meets the first prong of the well-accepted standard for

intellectual disability (significantly subaverage intellec­

tual functioning), evidence of the second prong (deficits in

adaptive behavior) can establish intellectual disability.

The Court offers little explanation for this sea change.

——————

11 See, e.g., Del. Code Ann., Tit. 11, §4209 (2007); Idaho Code §19–

2515A; Nev. Rev. Stat. §174.098 (2013); Va. Code Ann. §19.2–264.3:1.1

(Lexis Cum. Supp. 2013).

12 The longstanding views of professional organizations have also

been that intellectual functioning and adaptive behavior are independ­

ent factors. See, e.g., DSM–IV–TR, at 39. These organizations might

recommend examining evidence of adaptive behavior even when an IQ

is above 70, but that sheds no light on what the legal rule should be

given that most States appear to require defendants to prove each

prong separately by a preponderance of the evidence.

14 HALL v. FLORIDA

ALITO, J., dissenting

It asserts vaguely that “[i]t is not sound to view a single

factor as dispositive of a conjunctive and interrelated

assessment.” Ante, at 21. But the Court ignores the fact

that deficits in adaptive behavior cannot be used to estab­

lish deficits in mental functioning because the two prongs

are meant to show distinct components of intellectual

disability. “[I]ntellectual functions” include “reasoning,

problem solving, planning, abstract thinking, judgment,

academic learning, and learning from experience,” while

adaptive functioning refers to the ability “to meet devel­

opmental and sociocultural standards for personal inde­

pendence and social responsibility.” DSM–5, at 33.

Strong evidence of a deficit in adaptive behavior does not

necessarily demonstrate a deficit in intellectual function­

ing. And without the latter, a person simply cannot be

classified as intellectually disabled.

It is particularly troubling to relax the proof require­

ments for the intellectual-functioning prong because that

is the prong that most directly relates to the concerns that

led to our primary holding in Atkins. There, we explained

that “the diminished ability to understand and process

information, to learn from experience, to engage in logical

reasoning, or to control impulses”—i.e., diminished intel-

lectual functioning—“make it less likely that [a defendant]

can process the information of the possibility of execution

as a penalty” and therefore be deterred from committing

murders. 536 U. S., at 320; see also id., at 318 (“[T]hey

often act on impulse rather than pursuant to a premedi­

tated plan . . .”); see also ante, at 6. A defendant who does

not display significantly subaverage intellectual function­

ing is therefore not among the class of defendants we

identified in Atkins.

Finally, relying primarily on proof of adaptive deficits

will produce inequities in the administration of capital

punishment. As far as I can tell, adaptive behavior is a

malleable factor without “firm theoretical and empirical

Cite as: 572 U. S. ____ (2014) 15

ALITO, J., dissenting

roots.” See 2 Kaplan & Sadock’s 3448. No consensus

exists among States or medical practitioners about what

facts are most critical in analyzing that factor, and its

measurement relies largely on subjective judgments.

Florida’s approach avoids the disparities that reliance on

such a factor tends to produce. It thus promotes con­

sistency in the application of the death penalty and confi­

dence that it is not being administered haphazardly.

B

The Court’s second “interrelated” objection to Florida’s

rule is that it fails to account for the risk of error inherent

in IQ testing. In order to diminish this risk, the Court

establishes a rule that if IQ testing reveals an IQ between

71 and 75, a claim of intellectual disability cannot be

rejected on the basis of test scores alone. Ante, at 20. The

Court both misunderstands how the SEM works and fails

to explain why Florida’s method of accounting for the risk

of error (allowing a defendant to take and rely on multiple

tests) is not as effective as the approach that the Court

compels.

1

The Court begins with the simple and uncontroversial

proposition that every testing situation is susceptible to

error and thus may result in an imperfect measurement of

“true” IQ. The Court then wades into technical matters

that must be understood in order to see where the Court

goes wrong.

There are various ways to account for error in IQ test­

ing. One way is Florida’s approach (evaluate multiple test

results). Another is to use a mathematical measurement

called the “standard error of measurement” or SEM. See

AAMR 10th ed. 67–71 (App. 4.1). Of critical importance,

there is not a single, uniform SEM across IQ tests or even

across test-takers. Rather, “the [SEM] varies by test,

16 HALL v. FLORIDA

ALITO, J., dissenting

subgroup, and age group.” User’s Guide To Accompany

AAIDD 11th ed.: Definition, Classification, and Systems of

Supports 22 (2012).

Once we know the SEM for a particular test and a par­

ticular test-taker, adding one SEM to and subtracting one

SEM from the obtained score establishes an interval of

scores known as the 66% confidence interval. See AAMR

10th ed. 57. That interval represents the range of scores

within which “we are [66%] sure” that the “true” IQ falls.

See Oxford Handbook of Child Psychological Assessment

291 (D. Saklofske, C. Reynolds, & V. Schwean eds. 2013).

The interval is centered on the obtained score, and it

includes scores that are above and below that score by the

amount of the SEM. Since there is about a 66% chance

that the test-taker’s “true” IQ falls within this range, there

is about a 34% chance that the “true” IQ falls outside the

interval, with approximately equal odds that it falls above

the interval (17%) or below the interval (17%).

An example: If a test-taker scores a 72 on an IQ test

with a SEM of 2, the 66% confidence interval is the range

of 70 to 74 (72 ± 2). In this situation, there is approxi­

mately a 66% chance that the test-taker’s “true” IQ is

between 70 and 74; roughly a 17% chance that it is above

74; and roughly a 17% chance that it is 70 or below. Thus,

there is about an 83% chance that the score is above 70.

Similarly, using two SEMs, we can build a 95% confi­

dence interval. The process is the same except that we

add two SEMs to and subtract two SEMS from the ob­

tained score. To illustrate the use of two SEMs, let us

hypothesize a case in which the defendant’s obtained score

is 74. With the same SEM of 2 as in the prior example,

there would be a 95% chance that the true score is be­

tween 70 and 78 (74 ± 4); roughly a 2.5% chance that the

score is above 78; and about a 2.5% chance that the score

is 70 or below. The probability of a true score above 70

would be roughly 97.5%. As these two examples show, the

Cite as: 572 U. S. ____ (2014) 17

ALITO, J., dissenting

greater the degree of confidence demanded, the greater

the range of scores that will fall within the confidence

interval and, therefore, the further away from 70 an ob­

tained score could be and yet still have 70 fall within its

confidence interval.

2

The Court misunderstands these principles and makes

factual mistakes that will surely confuse States attempt­

ing to comply with its opinion.

First, the Court unjustifiably assumes a blanket (or very

common) error measurement of 5. See ante, at 20. That

assumption gives rise to the Court’s holding that a de­

fendant must be permitted to introduce additional evi­

dence when IQ tests reveal an IQ as high as 75. See ibid.

SEMs, however, vary by IQ test and test-taker, and there

is no reason to assume a SEM of 5 points; indeed, it ap­

pears that the SEM is generally “estimated to be three to

five points” for well-standardized IQ tests. AAMR 10th ed.

57. And we know that the SEM for Hall’s most recent IQ

test was 2.16—less than half of the Court’s estimate of 5.

Brief for Petitioner 40, n. 17.

Relatedly, the Court misreads the authorities on which

it relies to establish this cutoff IQ score of 75. It is true

that certain professional organizations have advocated a

cutoff of 75 and that Atkins cited those organizations’

cutoff. See ante, at 12, 20. But the Court overlooks a

critical fact: Those organizations endorsed a 75 IQ cutoff

based on their express understanding that “one standard

error of measurement [SEM]” is “three to five points for

well-standardized” IQ tests. AAMR, Mental Retardation

37 (9th ed. 1992) (hereinafter AAMR 9th ed.); Atkins, 536

U. S., 309, n. 5 (citing AAMR 9th ed.; 2 Kaplan & Sadock’s

2592 (B. Sadock & V. Sadock eds., 7th ed. 2000)); see also

AAMR 10th ed. 57; AAIDD 11th ed. 36. In other words,

the number 75 was relevant only to the extent that a

18 HALL v. FLORIDA

ALITO, J., dissenting

single SEM was “estimated” to be as high as 5 points.

AAMR 9th ed. 37. Here, by contrast, we know that the

SEM for Hall’s latest IQ test was less than half of that

estimate; there is no relevance to the number 75 in this

case. To blindly import a five-point margin of error when

we know as a matter of fact that the relevant SEM is 2.16

amounts to requiring consideration of more than two

SEMs—an approach that finds no support in Atkins or

anywhere else.

Because of these factual errors and ambiguities, it is

unclear to me whether the Court concludes that a defend­

ant is constitutionally entitled to introduce non-test evi­

dence of intellectual disability (1) whenever his score is 75

or lower, on the mistaken understanding that the SEM for

most tests is 5; (2) when the 66% confidence interval

(using one SEM) includes a score of 70; or (3) when the

95% confidence interval (using two SEMs) includes a score

of 70. In my view, none of these approaches is defensible.

An approach tied to a fixed score of 75 can be dismissed

out of hand because, as discussed, every test has a differ­

ent SEM.

The other two approaches would require that a defend­

ant be permitted to submit additional evidence when his

IQ is above 70 so long as the 66% or 95% confidence inter­

val (using one SEM or two SEMs, respectively) includes a

score of 70, but there is no foundation for this in our

Eighth Amendment case law. As Hall concedes, the

Eighth Amendment permits States to assign to a defend­

ant the burden of establishing intellectual disability by at

least a preponderance of the evidence. See Tr. of Oral Arg.

12. In other words, a defendant can be required to prove

that the probability of a 70 or sub-70 IQ is greater than

50%. Under the Court’s approach, by contrast, a defend­

ant could prove significantly subaverage intellectual func­

tioning by showing simply that the probability of a “true”

IQ of 70 or below is as little as 17% (under a one-SEM

Cite as: 572 U. S. ____ (2014) 19

ALITO, J., dissenting

rule) or 2.5% (under a two-SEM rule). This totally trans­

forms the allocation and nature of the burden of proof.

I have referred to the 66% and 95% confidence intervals

only because they result from the most straightforward

application of the SEM in this context: One SEM estab­

lishes the 66% confidence interval; two SEMs establish the

95% confidence interval. See AAIDD 11th ed. 36. But it

would be simple enough to devise a 51% confidence inter­

val—or a 99% confidence interval for that matter. There

is therefore no excuse for mechanically imposing stand­

ards that are unhinged from legal logic and that over-

ride valid state laws establishing burdens of proof. The

appropriate confidence level is ultimately a judgment best

left to legislatures, and their judgment has been that a

defendant must establish that it is more likely than not

that he is intellectually disabled. I would defer to that

determination.

3

The Court also fails to grasp that Florida’s system al­

ready accounts for the risk of testing error by allowing the

introduction of multiple test scores. The Court never

explains why its criticisms of the uncertainty resulting

from the use of a single IQ score apply when a defendant

consistently scores above 70 on multiple tests. Contrary to

the Court’s evident assumption, the well-accepted view is

that multiple consistent scores establish a much higher

degree of confidence.13

——————

13 See Oxford Handbook of Child Psychological Assessment 291

(D. Saklofske, C. Reynolds, & V. Schwean eds. 2013) (multiple scores

provide “greater precision”); A. Frances, Essentials of Psychiatric

Diagnosis: Responding to the Challenge of DSM–5, p. 31 (rev. ed. 2013)

(“The pattern of test scores is more important than the score on any

given test”). When there are multiple scores, moreover, there is good

reason to treat low scores differently from high scores: “Although one

cannot do better on an IQ test than one is capable of doing, one can

certainly do worse.” Forensic Psychology 56. (“[A] sharp, unexplained

20 HALL v. FLORIDA

ALITO, J., dissenting

The Court’s only attempt to address this is to say that

“the analysis of multiple IQ scores jointly is a complicated

endeavor,” ante, at 11, but any evaluation of intellectual

disability, whether based on objective tests or subjective

observations, is “complicated.” If conducting the proper

analysis of multiple scores produces an IQ as reliable as

the approach mandated by the Court, there is no basis for

rejecting Florida’s approach.14

* * *

For these reasons, I would affirm the judgment of the

Florida Supreme Court.

——————

drop in IQ scores following incarceration can be strong evidence of

malingering”); Frances, supra, at 31 (“[H]igher scores are likely to be

the more indicative, since there are many reasons why a given score

might underestimate a person’s intelligence, but no reason why scores

should overestimate it”).

14 The Court also states that because IQ testing itself may be flawed,

“multiple examinations may result in repeated similar scores” that are

“not conclusive evidence of intellectual functioning.” Ante, at 12. That

argument proves too much: If potential flaws in administering multiple

tests are sufficient to render them inaccurate, the Court should con­

clude that even scores of 90 or 100 are not sufficient. The appropriate

remedy for incorrectly administered tests is for a court to disregard

those tests, not to ignore the well-established fact that multiple, prop-

erly administered tests yielding scores above 70 can give a high degree

of confidence that an individual is not intellectually disabled.