United States v. Williams (1 F. Supp. 3d 1124, 2014)

ORDER DENYING DEFENDANT NAEEM WILLIAMS’ MOTION FOR PRETRIAL DETERMINATION THAT THE DEATH PENALTY CANNOT BE CARRIED OUT AGAINST NAEEM WILLIAMS BECAUSE OF A DISQUALIFYING MENTAL CAPACITY WITHIN THE MEANING OF 18 U.S.C. § 3596(c) AND ATKINS v. VIRGINIA, 536 U.S. 304 (2002)

J. MICHAEL SEABRIGHT, District Judge.

I. INTRODUCTION

The United States has charged Defendant Naeem Williams (“Defendant” or “Williams”) with crimes that qualify him for possible imposition of the death penalty under 18 U.S.C. §§ 3591 & 3592. Defendant has moved pursuant to 18 U.S.C. § 3596(c), and Atkins v. Virginia, 536 U.S. 304, 122 S.Ct. 2242, 153 L.Ed.2d 335 (2002), for a pretrial determination that the death penalty cannot be carried out against him because of a disqualifying mental capacity — ie., that he is “intellectually disabled.” Doc. No. 2064. The court has analyzed the extensive evidence taken during nine days of testimony in September and December 2013 (as well as other evidence in the record specifically proffered by the parties), and has carefully considered the written arguments filed by both sides. Based on the following, the court concludes that Defendant has failed to prove by a preponderance of the evidence that he has such a disqualifying condition. Accordingly, Defendant’s Motion is DENIED.

The court first explains the relevant procedural background leading to the Atkins hearings, and summarizes the witnesses who testified in September and December 2013 (and in prior related proceedings in this case). The substance of the evidence, however, is best understood in light of the applicable legal and clinical standards. The court thus analyzes the specific testimony and evidence in the Analysis section of this Order, after examining the relevant standards in the Discussion section.

II. PROCEDURAL BACKGROUND

A. Charges Against Defendant

The Second Superseding Indictment (“Indictment”) charges Defendant with two capital-eligible Counts arising out of his role in allegedly beating and killing his five-year-old daughter. Specifically, Count One charges Defendant with first degree felony murder, in violation of 18 U.S.C. §§ 7 & 1111. Doc. No. 1004, Indictment at 2. It alleges that on July 16, 2005, Defendant, with malice aforethought, unlawfully killed a child, in the perpetration of child abuse, at Wheeler Army Airfield. Id. Count Two charges Defendant with first degree felony murder, and aiding and abetting first degree felony murder, in violation of 18 U.S.C. §§ 7 & 1111. It alleges that sometime after December 13, 2004, and culminating on July 16, 2005, Defendant and his wife, Delilah Williams, with malice aforethought, unlawfully killed, and aided and abetted each other in the killing of, a child in the perpetration of a pattern and practice of assault and torture against a child. Id. at 3.

The Indictment contains a Notice of Special Findings section, alleging mental state eligibility factors and statutory aggravating factors under 18 U.S.C. §§ 3591(a) & 3592(c). In particular, it alleges that Defendant:

a. intentionally inflicted serious bodily injury that resulted in the death of Talia Williams (18 U.S.C. § 3591(a)(2)(B));

b. intentionally and specifically engaged in an act of violence, knowing that the act created a grave risk of death to a person, other than one of the participants in the offense, such that participation in the act constituted a reckless disregard for human life and the victim, Talia Williams, died as a direct result of the act (18 U.S.C. § 3591(a)(2)(D));

c. committed the offense charged in the indictment in an especially heinous, cruel, and depraved manner in that it involved torture and serious physical abuse to the victim, Talia Williams (18 U.S.C. § 3592(c)(6)); and

d. committed the offense charged in the indictment against a victim, Ta-lia Williams, who was particularly vulnerable due to her youth (18 U.S.C. § 3592(e)(ll)).

Id. at 4.

At the time of the alleged crimes, Defendant was a Specialist (enlisted rank of E-4) on active duty in the United States Army, stationed at Schofield Barracks in Wahiawa, Hawaii. See, e.g., Gov’t’s Ex. 3, Denney Rpt. at 6. Federal jurisdiction arises because the alleged crimes occurred “within the special maritime and territorial jurisdiction of the United States, to wit, Wheeler Army Airfield[J” Doc. No. 1004, Indictment at 2.

B. Prior Expert Witness Testimony and Evidence

On November 9, 2007 and April 12, 2008, Defendant filed Notices of Expert Evidence of a Mental Condition pursuant to Federal Rule of Criminal Procedure 12.2(b). Doc. Nos. 416 & 554. By these Notices, Defendant indicated that he “intends [to] introduce expert evidence relating to mental condition bearing on (1) the issue of guilt during the guilt trial and (2) on the issue of punishment during any penalty hearing in this capital case[.]” Doc. No. 554, Def.’s Notice at 1. In this regard, several expert witnesses — clinical and social psychologists, neuropsycholo-gists, and psychiatrists — had previously been or were later retained and proffered opinions as to (among other matters) Defendant’s mental condition as related to his capacity to form the requisite intent charged in the Indictment. Specifically, Defendant has claimed he is or was suffering from “borderline intellectual functioning” (“BIF”) (a distinct, although perhaps related, issue from the Atkins question presently before the court). As described in a prior Order, BIF is a condition (or description of a condition) the existence of which might be relevant in understanding whether Defendant had the necessary “mens rea” as charged in the Indictment. See, e.g., Doc. No. 780, Order Denying Government’s Amended Motion To Exclude the Defendant’s Mental Health Expert Witnesses at the Guilb-Phase (“Guilt Phase Order”) at 18-19 (Feb. 20, 2009) (Ezra J.).

In July and October 2008, the government filed Motions seeking to exclude Defendant’s mental health expert witnesses at the guilt phase, and requested hearings under Daubert v. Merrell Dow Pharmaceuticals, 509 U.S. 579, 113 S.Ct. 2786, 125 L.Ed.2d 469 (1993). See Doc. Nos. 639 & 715. Accordingly, Judge Ezra conducted a Daubert evidentiary proceeding from November 3 through 6, 2008, and ultimately denied the government’s request to exclude Defendant’s witnesses at the guilt phase. See Doc. No. 780, Guilt Phase Order at 47. As part of these 2008 Daubert proceedings, Defendant proffered testimony and opinions from Dr. Myla Young (a neuropsychologist) and Dr. Pablo Stewart (a clinical psychiatrist). They opined, among other beliefs, that Defendant suffers from BIF and brain damage which impairs his ability to understand and adapt to stressful situations. Id. at 4. The government responded with Dr. Philip Resnick (a forensic psychiatrist) and Dr. Harold Hall (a psychologist and forensic neuropsychologist), who critiqued Drs. Young and Stewart’s diagnoses and methodology. Id. Some of the evidence from this 2008 proceeding is relevant towards Atkins issues, as explained further below.

As a result of testimony during the November 2008 hearings, a question arose regarding Defendant’s competency to stand trial. On March 9, 2009, Judge Ezra issued an Amended Order Granting the Government’s Motion for: (1) a Hearing to Determine the Mental Competency of the Defendant to Stand Trial; and (2) a Psychiatric and Psychological Examination of the Defendant. Doc. No. 796. That Order led to examinations in 2009 of Defendant by United States Bureau of Prisons Drs. Elizabeth Tyner and Dr. Lea Ann Preston Baecht, and a June 2009 Forensic Report by Dr. Preston Baecht. See, e.g., Doc. No. 826, Order Re. Competency Rpt.; Doc No. 2065-5, Tr. June 25, 2012 (Dr. Tyner) at 27-28. On August 31, 2009, Defendant was found competent to stand trial. See Doc. Nos. 859 (oral ruling), 865 (written order).

For various reasons, the competency proceedings eventually led to Defendant’s May 29, 2012 Motion to Exclude or Limit Testimony of Dr. Preston Baecht or Other Competence-Related Examiners. Doc. No. 1853. As a result, Judge Ezra held Daubert evidentiary hearings in June and August 2012, during which the court heard testimony from Drs. Tyner, Preston Baecht, and defense witness Dr. Kyle Boone. These 2012 Daubert hearings, like the 2008 Daubert hearings, resulted in some evidence also relevant to Atkins issues — and the parties have also proffered specific testimony from these 2012 proceedings for the court’s consideration here.

Meanwhile, the government retained a neuropyschologist, Dr. Diana Goldstein, as a rebuttal witness as to Defendant’s BIF theory. As part of her duties, Dr. Gold-stein evaluated Defendant and conducted various neuropsychological tests in 2010. Dr. Goldstein’s opinions were not proffered in this Atkins proceeding, but the parties have agreed that “raw test scores reported by Dr. Diana Goldstein, including Dr. Goldstein’s WAIS-PV scores, and her neu-ropsychological assessment scores, can be used by the parties’ mental health experts as bases for opinions on Mr. Williams’s intellectual functioning and mental condition at the time of testing.” Doc. No. 2176, Stipulation Concerning Dr. Diana Goldstein’s Data and Scoring Opinions at 2. The parties also stipulated that Dr. Goldstein’s actual opinions as reflected in her reports shall not be the basis for any opinion by another expert — that is, the parties were permitted to consider Dr. Goldstein’s test results but not rely on her opinions, interpretations, or analysis of those results. Id. at 2-3. Accordingly, some of Dr. Goldstein’s 2010 test results are in this Atkins record, and were considered by witnesses from both sides.

C. Atkins Evidentiary Hearings

On July 3, 2013, Defendant filed his “Motion for a Pretrial Determination That the Death Penalty Cannot Be Carried out Against Naeem Williams Because of a Disqualifying Mental Capacity Within the Meaning of 18 U.S.C. § 3596(c), and Atkins v. Virginia.” Doc. No. 2064. The government filed its initial Opposition on October 4, 2013. Doc. No. 2188.

Meanwhile, on September 9, 2013, this court heard testimony from Dr. Thomas Oakland (a proposed government rebuttal witness) during further Daubert proceedings as to the propriety of his (and other witnesses’) possible testimony during the guilt phase of the trial. The parties agreed that Dr. Oakland’s testimony is also relevant towards Atkins issues, and subsequently stipulated to submit Dr. Oakland’s September 9, 2013 testimony as it was given in that Daubert hearing as part of the government’s case in the Atkins proceeding. See Doc. No. 2246, Tr. Dec. 13, 2013 (Dr. Oakland) at 172. Dr. Oakland’s September 9, 2013 testimony was thus designated as part of the Atkins record. See Def.’s Ex. F; Gov’t’s Ex. 47.

The court held Atkins hearings on December 3, 2013; on December 11-13, 2013; and on December 16-19, 2013. On those days, the court admitted evidence and heard testimony for Defendant from Drs. Joette James, Kyle Boone, and George Woods. And for the government, the court heard testimony from Drs. Robert Denney and Linda Gottfredson. Post-hearing Briefs were filed on January 13, 2014, Doc. Nos. 2279, 2281, and Replies were filed on January 17, 2014. Doc. Nos. 2285, 2286.

To summarize, in all, the court considered evidence and testimony from the following (including the witnesses who testified in 2008 and 2012):

1. Dr. Myla Young

Dr. Young was retained as an expert witness for Defendant. As described in the 2009 Guilt Phase Order:

Dr. Young earned her Ph.D. from what was formerly known as the California School of Professional Psychology in 1988. She was licensed in the State of California as a psychologist in 1990, and is certified by the American Board of Professional Neuropsychology. Dr. Young focuses on neuropsychological assessment and has spent a significant period of her career on the staff of the California Department of Mental Health Program at the Correctional Medical Facility in Vacaville, California. As a result, Dr. Young has experience in assessment of individuals within the correctional setting and has participated as a principal investigator in several studies conducted by the California Department of Health.

Doc. No. 780, Guilt Phase Order at 10. She was accepted by the court as an expert in neuropsychology. Doc. No. 2065-2, Tr. Nov. 4, 2008 (Dr. Young) at 30.

Over a period of approximately five days beginning in January 2006, Dr. Young administered a variety of neuropsycho-logical and psychological tests and assessment tools to assess Defendant’s neural functioning.... These procedures tested, among other things, Defendant’s intellectual functioning, his motor, attention, memory and learning skills, and his executive functioning. Among these tests were the [WAIS-III] and the Test of Non-Verbal Intelligence (“TONI-3”), which have been generally accepted as reliable and valid measures of intelligence. [Atkins, 536 U.S. at 309 n. 5, — S.Ct. at -] (describing WAIS-III as “the standard instrument in the United States for assessing intellectual functioning”); [Doc. No.2065-2,] Nov. 4[, 2008] Tr. at 64:8-13 (Dr. Young stating “[t]he most frequently used test of nonverbal IQ is the TONI-3”).

Doc. No. 780, Guilt Phase Order at 11.

2. Dr. Pablo Stewart

Defendant presented Dr. Stewart in 2008, also to opine regarding BIF and its effect, if any, on Defendant’s capacity to form the mens rea charged in the Indictment. See, e.g., id. at 33. As set forth in the Guilt Phase Order, Dr. Stewart is:

a physician licensed to practice medicine in California and Hawaii who is board certified in psychiatry by the American Board of Psychiatry and Neurology. Dr. Stewart completed his medical and psychiatric training at the University of •California in 1986 and has practiced in a number of settings, including jails, jail psychiatric hospitals, and Veterans’ Administration hospitals. Dr. Stewart has qualified as an expert in seven federal courts and several state courts.

Id. at 31-32. In November 2008, the court qualified Dr. Stewart as an expert in psychiatry. Doc. No. 2065-1, Tr. Nov. 3, 2008 (Dr. Stewart) at 36.

Dr. Stewart interviewed Defendant for a total of 13 to 14 hours over a period of more than two years and reviewed anecdotal records, including interviews of family members, social history, and ah interview with Delilah [Williams]. Dr. Stewart also reviewed some of the testing conducted by Dr. Young.

Doc. No. 780, Guilt Phase Order at 32-38. Dr. Stewart did not testify at the Atkins proceeding, although he was present in court for many of the hearings — Defendant notified the court on December 11, 2013 of Dr. Stewart’s presence so as to observe testimony of various witnesses (and the court recognized his attendance on that day and on other days), and the government did not object to his presence. Doc. No. 2259, Tr. Dec. 11, 2013 at 5.

3. Dr. Phillip Resnick

Dr. Resnick is a board-certified psychiatrist and professor of psychiatry at Case Western Reserve University. Doc. No.2065-3, Tr. Nov. 5, 2008 (Dr. Resnick) at 104-05. He was retained by the government, and qualified by the court in November 2008 as an expert in forensic psychiatry. Id. at 107. He offered an opinion during the 2008 Daubert hearings on Drs. Young and Stewart’s diagnosis and methodology. Doc. No. 780, Guilt Phase Order at 4.

4. Dr. Howard Hall

Dr. Hall was retained by the government as a rebuttal witness, and opined in 2008 on testimony or procedures of Drs. Young and Stewart as discussed above. He has a doctorate in clinical psychology, and is board-certified in three areas: clinical psychology, forensic psychology, and neuropsychology. Doc. No.2065-4, Tr. Nov. 6, 2008 (Dr. Hall) at 5-6. He has been qualified as an expert witness “several hundred times since the late 1970’s” in state, military, and federal courts. Id. at 7. The court qualified him in November 2008 as an expert in forensic neuropsychol-ogy. Id.

5. Dr. Lee Ann Preston Baecht

Dr. Preston Baecht performed a comprehensive competency examination (assisted by Dr. Tyner), and prepared a forensic report for the court for competency purposes in 2009. She has a doctorate degree in clinical psychology, and is a licensed psychologist in the State of Indiana. See Doc. No. 1928, Order Denying Def.’s Mot. to Exclude or Limit Testimony at 10-11. She is board certified in forensic psychology, and has been employed full-time as a clinical psychologist in the forensic evaluation unit at the United States Medical Center for Federal Prisoners (“MCFP”) of the Bureau of Prisons (“BOP”) in Springfield, Missouri since 2000. Id. Among other duties, she conducts court-ordered forensic evaluations to address competency, responsibility, the need for mental health treatment, and dangerousness of defendants or prisoners. Id. at 11. The court qualified her in August 2012 as an expert in forensic psychology. Doc. No.2065-6, Tr. Aug. 7, 2012 (Dr. Peston Baecht) at 14-15.

6. Dr. Elizabeth Tyner

Dr. Tyner obtained her doctorate in clinical psychology, with a focus in forensic psychology in 2008. See Doc. No.1928, Order Denying Def.’s Mot. to Exclude or Limit Testimony at 10. She was licensed in the State of Washington as a psychologist in October 2009. Id. She completed a clinical internship and postdoctoral residency at the MCFP in 2009, and has worked there since 2009 as a clinical psychologist. During her postdoctoral residency, Dr. Tyner conducted (with assistance of, or supervision by, Dr. Preston Baecht) a WAIS-III intelligence test of Defendant. See Doc. No.2065-5, Tr. June 25, 2012 (Dr. Tyner) at 27-28. The court qualified Dr. Tyner in June 2012 as an expert in clinical psychology. Id. at 26.

7. Dr. Thomas Oakland

As described above, the government submitted Dr. Oakland’s September 9, 2013 Daubert testimony as rebuttal in this Atkins proceeding. Dr. Oakland has a doctorate in educational psychology, and has over forty years of experience as, among other positions, a professor of educational psychology at the Universities of Texas and Florida. Doc. No. 2172, Tr. Sept. 9, 2013 (Dr. Oakland) at 19. Among other areas, Dr. Oakland has an academic and clinical background working with the intellectually disabled. Id. at 21. He, along with Dr. Patti Harrison, developed a standardized test for assessing adaptive behavior-the Adaptive Behavior Assessment System (“ABAS”). Id. The ABAS-II is now one of the generally accepted methods of measuring adaptive functioning. Id. at 21-22. On September 9, 2013, this court qualified Dr. Oakland as an expert in the assessment of adaptive functioning, id. at 18, and admitted portions his October 2011 report (as amended on June 22, 2012) that relate to adaptive functioning. Id. at 20-21; Gov’t’s Ex. 59.

8.Dr. Joette James

Dr. James is a board-certified (April 2013) clinical neuropsychologist with a doctorate degree in clinical psychology. Doc. No. 2259, Tr. Dec. 11, 2013 (Dr. James) at 6, 8, 11, 112. She is employed by Children’s National Medical Center in Washington D.C., and is an assistant professor in the Departments of Pediatrics and Psychiatry and Behavioral Sciences, at the George Washington University Medical Center. Def.’s Ex. 1003. She has testified in several capital cases, including opining on Atkins matters. Doc. No. 2259, Tr. Dec. 11, 2013 (Dr. James) at 113. On December 11, 2013, this court permitted Dr. James to testify as an expert neurop-syehologist, and in the field of assessment of neuropsychology and intelligence. Id. at 17.

Among other matters, Dr. James administered a formal neuropsychological evaluation of Defendant in February and April 2013, which included a Stanford-Binet Intelligence Scales (Fifth Edition) (“SB-V”) intelligence test. See Def.’s Exs. 1005, 1006. During the Atkins hearings, Defendant submitted Dr. James’ “Summary Report of Neuropsychological Evaluation— Revised,” Def.’s Ex. 1004; a “Neuropsy-chological Evaluation Test Summary,” Def.’s Ex. 1005; and a November 2013 “Supplement Report of Evaluations,” Def.’s Ex. 1006.

9. Dr. George Woods

Dr. Woods is a board-certified psychiatrist who also teaches at the University of California Berkeley School of Law and at Morehouse School of Medicine. Doc. No. 2262, Tr. Dec. 16, 2013 (Dr. Woods) at 6-7. He has over thirty years of experience as a clinical psychiatrist, neuropsychiatrist, and forensic psychiatrist. Id. at 6, 8-10. He has performed over forty Atkins examinations, and testified as an expert witness in approximately seven cases. Id. at 12. On December 16, 2013, Dr. Woods was permitted to testify as an expert in forensic neuropsychiatry and intellectual disabilities, id. at 19, and Defendant submitted Dr. Woods’ July 29, 2013 Report opining on Defendant’s mental capacity. Def.’s Ex. 1002.

10. Dr. Kyle Boone

Dr. Boone is a board-certified clinical neuropsychologist and a professor. Doc. No. 2260, Tr. Dec. 12, 2013 (Dr. Boone) at 130, 133. She was formerly affiliated with Harbor-UCLA Medical Center in California, and is now a clinical professor in the Department of Psychiatry at UCLA and a professor at the California School of Forensic Studies at Alliant International University. Id. at 134; Def.’s Ex. 1007. She has published, in the area (among others) of symptom or “performance validity” of neuropsychological assessment, Doc. No. 2260, Tr. Dec. 12, 2013 (Dr. Boone) at 142, which she describes as “measuring] whether or not someone is in fact performing to true ability.” Id. at 144.

On December 12, 2013, Dr. Boone was accepted as an expert on “neuropsychological assessment, including the standards of practice applicable to intelligence testing, neuropsychological assessment, the assessment of effort, performance validity and malingering.” Id. at 163. During the Atkins hearings, Defendant submitted her July 20, 2012 Report, and a November 21, 2013 Supplemental Report. Def.’s Exs. 1008,1009.

11. Dr. Robert Denney

Dr. Denney is a clinical neuropsychologist, forensic psychologist, and professor. Doc. No. 2263, Tr. Dec. 17, 2013 (Dr. Den-ney) at 187. He obtained his doctorate in psychology in 1991, and worked as a forensic psychologist at the BOP’s Medical Center from 1990 to 2000. Id. at 189. He “performed pretrial criminal forensic evaluations for the U.S. District Courts from ... January of 1992 through February of 2000.” Id. These evaluations included “competency to stand trial and sanity-related evaluations,” and determinations of intellectual disability. Id. at 190. From 2000 until his retirement from the BOP in 2011, he continued to work at “the medical and surgical sides” of the MCFP, “pro-vid[ing] mental health services, [and] neu-ropsychological diagnostic services.” Id. at 191. Since his retirement, he practices as a forensic neuropsyeholgist, id. at 202, and is an associate professor and coordinator of clinical neuropsychology at the Forest Institute of Professional Psychology. Id. at 192; Gov’t’s Ex. 4.

On December 17, 2013, the court qualified Dr. Denney as an expert in neuropsy-chology and forensic psychology. Doc. No. 2263, Tr. Dec. 17, 2013 (Dr. Denney) at 204. During the Atkins hearings, the government submitted Dr. Denney’s September 23, 2013 Neuropsychological Report of Defendant. Gov’t’s Ex. 3.

12. Dr. Linda Gottfredson

Dr. Gottfredson is a professor in the School of Education at the University of Delaware. Doc. No. 2246, Tr. Dec. 3, 2013 (Dr. Gottfredson) at 18. She has a doctorate degree in sociology from the Johns Hopkins University. Id. She teaches and has published in the general area of intelligence and its assessment, see, e.g., Gov’t’s Ex. 1-8, and she is cited in clinical sources (as discussed below) as having at least some responsibility for an accepted definition of “intelligence” — i.e., that there is a single “general factor of intelligence,” known as “g”. See, e.g., Doc. No. 2246, Tr. Dec. 3, 2013 (Dr. Gottfredson) at 32; Def.’s Ex. 1015. She is, however, not a psychologist or psychiatrist, and has never previously testified or been qualified as an expert witness in any court. See, e.g., Doc. No. 2246, Tr. Dec. 3, 2003 at 19 & 34.

Dr. Gottfredson testified on December 3, 2013, as a government rebuttal witness (both as to Atkins issues and as a potential government witness at the guilt phase regarding BIF). The government also proffered her September 19, 2013 Report, along with six appendices to that Report. See Gov’t’s Exs. 1, 1-1 to 1-10, and 2. At the hearing, the court permitted her to testify for Atkins purposes as an expert in the field of human intelligence, and subject to a renewed Daubert motion as to the use of her testimony. Doc. No. 2246, Tr. Dec. 3, 2013 (Dr. Gottfredson) at 38. On December 27, 2013, Defendant renewed his challenge to the use of her testimony by filing a “Motion to Exclude or Widely Limit Use of Dr. Linda Gottfredson’s September 2013 Report and December 3, 2013 Testimony on Atkins and Cognitive Functioning Assessment,” Doc. No. 2255, which the court rules upon in a separate Order.

III. DISCUSSION

Two provisions (statutory and constitutional) forbid federal courts from imposing the death penalty on the intellectually disabled — the Federal Death Penalty Act of 1994 (“FDPA”) and the Eighth Amendment. In particular, the FDPA specifically provides that a “sentence of death shall not be carried out upon a person who is mentally retarded.” 18 U.S.C. § 3596(c). Atkins later held, in addressing state law, that the execution of the mentally retarded is excessive and violates the Eighth Amendment (“Excessive bail shall not be required, nor excessive fines imposed, nor cruel and unusual punishments inflicted.”). Thus, under Atkins, “the federal policy embodied in the [FDPA] became a constitutional imperative[.]” United States v. Davis, 611 F.Supp.2d 472, 473 (D.Md. 2009). Applying these provisions gives rise to several procedural and substantive issues, which the court addresses next.

A. Procedural Standards

Whether an individual is intellectually disabled “is a question of fact[.]” Clark v. Quarterman, 457 F.3d 441, 444 (5th Cir.2006); see also, e.g., Walker v. Kelly, 593 F.3d 319, 323 (4th Cir.2010) (reviewing finding that defendant was not intellectually disabled, stating that “the determination of mental retardation involves a question of fact”). “[I]t is a condition, the existence of which disqualifies a person from capital pumshment[.]” Davis, 611 F.Supp.2d at 474 (citing Walker v. True, 399 F.3d 315, 326 (4th Cir.2005)). But “[t]he standard for whether someone is [intellectually disabled] and ineligible for the death penalty ... is a legal matter[.]” United States v. Wilson, 922 F.Supp.2d 334, 342 (E.D.N.Y.2013).

In this regard, Williams (in his original filing on this Motion) asks the court to require the government to prove that he is eligible for the death penalty — that is, to prove that he is not intellectually disabled. For this proposition, he cites Ring v. Arizona, 536 U.S. 584, 122 S.Ct. 2428, 153 L.Ed.2d 556 (2002) (holding in a capital case that the government has the burden to prove aggravating factors before a jury that are necessary for imposition of the death penalty, consistent with Apprendi v. New Jersey, 530 U.S. 466, 120 S.Ct. 2348, 147 L.Ed.2d 435 (2000)).

The court, however, agrees with and follows the ample case law holding precisely the opposite — in a federal case, the defendant bears the burden of proving an Atkins claim by a preponderance of the evidence. See, e.g., In re Johnson, 334 F.3d 403, 405 (5th Cir.2003) (“[Neither Ring and Apprendi nor Atkins render the absence of mental retardation the functional equivalent of an element of capital murder which the [prosecution] must prove beyond a reasonable doubt.”); United States v. Candelario-Santana, 916 F.Supp.2d 191, 193 (D.P.R.2013) (“Every district court that has addressed the issue that we are aware of has held [that the defendant bears the burden of proof on this issue by a preponderance of the evidence.]”); Davis, 611 F.Supp.2d at 474 (“[B]eeause [intellectual disability] is a disqualifying condition, the Court ... assigned to [defendant] the burden of establishing, by a preponderance of the evidence, that he is [intellectually disabled.]”); United States v. Sablan, 461 F.Supp.2d 1239, 1242-43 (D.Colo.2006) (same).

Similarly, a defendant has no constitutional right to a jury trial on an Atkins claim, a point that the parties have not disputed. See, e.g., Walker, 399 F.3d at 324-27 (rejecting argument that defendant was entitled to a jury on an Atkins claim); Smith v. Ryan, 2012 WL 6019055, at *10-11 (D.Ariz. Dec. 3, 2012) (refusing to find a right to a jury determination on intellectual disability, in part because “state and federal courts have rejected the argument that [intellectual disability] is an element of the offense which must be proven to a jury pursuant to [Apprendi] and its progeny”); Maldonado v. Thaler, 662 F.Supp.2d 684, 706 (S.D.Tex.2009) (“[T]he factfinder with respect to a determination of [intellectual disability] need not be a jury[.]”) (quoting In re Woods, 155 Fed.Appx. 132, 135-36 (5th Cir.2005)); Walker, 399 F.3d at 326 (“[A] finding of mental retardation ... is analogous to the question of competency to be executed in death penalty cases, which need not be decided by a jury.”) (quoting Walton v. Johnson, 269 F.Supp.2d 692, 698 n. 3 (W.D.Va.2003)).

Although an intellectual disability “is not a defense,” Davis, 611 F.Supp.2d at 474, the requirement for a defendant to prove an intellectual disability fits completely within the framework explained in Dixon v. United States, 548 U.S. 1, 7-8, 126 S.Ct. 2437, 165 L.Ed.2d 299 (2006) (finding it constitutional to place the burden on the defendant to establish duress by a preponderance of the evidence). Among other reasoning, Dixon reaffirmed that “at common law, the burden of proving ‘affirmative defenses — indeed, “all ... circumstances of justification, excuse or alleviation” — rested on the defendant.’ ” Id. at 8, 126 S.Ct. 2437 (quoting Patterson v. New York, 432 U.S. 197, 202, 97 S.Ct. 2319, 53 L.Ed.2d 281 (1977)).

In short,, the “ultimate issue” of whether a defendant is, in fact, intellectually disabled is for the court to decide (and for Williams to prove by a preponderance of the evidence), “based upon all of the evidence and determinations of credibility.” Wilson, 922 F.Supp.2d at 343 (citation omitted).

B. Substantive Standards — A Definition of “Intellectual Disability” Informed by Established Clinical Standards

Neither the FDPA nor Atkins adopted a precise standard for determining whether a person has an intellectual disability. The FDPA provides no parameters for the term “mentally retarded,” and — as the Ninth Circuit recently reiterated — “Atkins did not define mental retardation as a matter of federal law.... [Rather,] the Supreme Court left to the states ‘the task of developing appropriate ways to enforce the constitutional restriction upon [their] execution of sentences.’ ” Pizzuto, 729 F.3d at 1216 (quoting Moormann v. Schriro, 672 F.3d 644, 648 (9th Cir.2012) (in turn, quoting Atkins)).

Nevertheless, Atkins, referred to clinical definitions as set forth by the American Association on Intellectual and Developmental Disabilities (“AAIDD”) (formerly the American Association on Mental Retardation (“AAMR”)) and the American Psychiatric Association (“APA”). 536 U.S. at 308 n. 3, 122 S.Ct. 2242; see also id. at 318, 122 S.Ct. 2242. And thus, in the Atkins context, federal courts have been guided primarily by such clinical standards in determining whether a defendant is intellectually disabled when facing federal charges. See, e.g., Wilson, 922 F.Supp.2d at 339 (citing numerous district court cases); see also, e.g., Ortiz v. United States, 664 F.3d 1151, 1157 (8th Cir.2011) (discussing the APA’s and AAIDD’s definitions of intellectual disability in reviewing a federal district court’s 28 U.S.C. § 2255 Atkins decision). In that light, both parties here have structured their arguments and proffered evidence based mostly on clinical standards.

Accordingly, as a framework, this court relies chiefly on the professional clinical standards established by the APA and AAIDD in assessing whether Defendant is intellectually disabled within the meaning of Atkins. The court, however, also emphasizes that it is making a legal (not a medical or psychological) determination. See, e.g., Ortiz, 664 F.3d at 1168 (rejecting an argument that “established science ... dictates a mental retardation diagnosis” because it “incorrectly assumes the Atkins decision delegates to the scientific community the finding of whether an individual is mentally retarded”); Hooks, 689 F.3d at 1172 (emphasizing that “a clinical standard is not a constitutional command”). “Atkins ‘did not delegate to psychologists the determination of whether an inmate should not face execution.’ ” Wilson, 922 F.Supp.2d at 339 (quoting United States v. Bourgeois, 2011 WL 1930684, at *24 (S.D.Tex. May 19, 2011)). Rather, “‘psychology informs, but does not determina-tively decide, whether an inmate is exempt from execution,’ leaving the ‘contours of the constitutional protection to the courts.’ ” Ortiz, 664 F.3d at 1168 (quoting Bourgeois, 2011 WL 1930684, at *24). And so — informed by clinical definitions— the court ultimately “will apply its own judgment as to the ‘appropriate ways’ to enforce the ultimately legal prohibition on executing [intellectually disabled] offenders,” Wilson, 922 F.Supp.2d at 339 (quoting Atkins, 536 U.S. at 317, 122 S.Ct. 2242), particularly when facing ambiguous or conflicting definitions and testimony. Id.

C. Clinical Standards

1. A Three-Prong Test

The APA and AAIDD have promulgated evolving definitions of intellectual disability. All these clinical definitions, however, require three basic elements or criteria: (1) significant deficits in intellectual functioning; (2) deficits or impairments in adaptive functioning or behavioral skills; and (3) onset of the condition before age eighteen (or the “developmental period”).

In particular, until 2013, the APA gave the following three “diagnostic criteria for mental retardation:”

A. Significantly subaverage intellectual functioning: an [intelligence quotient (“IQ”) ] of approximately 70 or below on an individually administered IQ test....

B. Concurrent deficits or impairments in present adaptive functioning (i.e., a person’s effectiveness in meeting the standards expected for his or her age by his or her cultural group) in at least two of the following areas: communication, self-care, home living, social/interpersonal skills, use of community resources, self-direction, functional academic skills, work, leisure, health and safety.

C. The onset is before age 18 years.

APA, Diagnostic and Statistical Manual of Mental Disorders (4th ed. 2000) (Text Revision) (“DSM-IV-TR”) at 49. The APA instructed users of the DSM-IV-TR to:

Code based on degree of severity reflecting level of intellectual impairment:

317 Mild Mental Retardation: IQ level 50-55 to approximately 70

318.0 Moderate Mental Retardation: IQ level 35-40 to 50-55

Severe Mental Retardation: IQ level 20-25 to 35-40 CO 1 — l CO

Profound Mental Retardation: IQ level below 20 or 25 CO i — ‘ OO to

Mental Retardation, Severity Unspecified: when there is strong presumption of Mental Retardation but the person’s intelligence is untestable by standard tests. CO J — l CO

Id.

The APA revised the DSM-IV-TR with the 2013 publication of the Diagnostic and Statistical Manual of Mental Disorders (5th ed. 2013) (“DSM-5”). The DSM-5 provides the following “diagnostic criteria” for “Intellectual Disability (Intellectual Developmental Disorder):”

Intellectual disability (intellectual development disorder) is a disorder with onset during the developmental period that includes both intellectual and adaptive functioning deficits in conceptual, social, and practical domains. The following three criteria must be met:

A. Deficits in intellectual functions, such as reasoning, problem solving, planning, abstract thinking, judgment, academic learning, and learning from experience, confirmed by both clinical assessment and individualized, standardized intelligence testing.

B. Deficits in adaptive functioning that result in failure to meet developmental and sociocultural standards for personal independence and social responsibility. Without ongoing support, the adaptive deficits limit functioning in one or more activities of daily life such as communication, social participation, and independent living, across multiple environments, such as home, school, work, and community.

C. Onset of intellectual and adaptive deficits during the developmental period.

Def.’s Ex. 1019, DSM-5 at 33. Under the DSM-5, the level of severity of intellectual disability is no longer classified specifically in terms of IQ. Rather, “[t]he various levels of severity [in the DSM-5] are defined on the basis of adaptive functioning, and not IQ scores, because it is adaptive functioning that determines the level of supports required. Moreover, IQ measures are less valid in the lower end of the IQ range.” Id. That is, although it certainly still refers to consideration of IQ scores, the DSM-5 “de-emphasizes IQ scores as determinants of [intellectual disability].” Hernandez v. Stephens, 537 Fed.Appx. 531, 533 n. 1 (5th Cir.2013).

The AAIDD’s standards are similar to the APA’s. Indeed, prior to the 2013 release of the DSM-5, courts characterized the standards as “essentially identical.” Wilson, 922 F.Supp.2d at 341 (citing cases). In its 2010 Manual Intellectual Disability: Definition, Classification, and Systems of Supports (11th ed. 2010) (“2010 AAIDD Manual” or “the Green Book” as referred to during the Atkins hearings), the AAIDD defines intellectual disability as “characterized by significant limitations both in intellectual functioning and in adaptive behavior as expressed in conceptual, social, and practical adaptive skills. This disability originates before 18.” Wilson, 922 F.Supp.2d at 341 (quoting 2010 AAIDD Manual at 1). This is the same general definition given in the prior (2002) version of the AAMR/AAIDD Manual. See Def.’s Ex. 1014, AAMR, Mental Retardation: Definition, Classification, and Systems of Supports (10th ed. 2002) at 93 (“2002 AAMR Manual”) (“Mental retardation is a disability characterized by significant limitations both in intellectual functioning and in adaptive behavior as expressed in conceptual, social, and practical skills. This disability originates before age 18.”).

2. Clinical Judgment and a Comprehensive Analysis

The APA and AAIDD clinical manuals— both (1) the APA’s DSMIV-TR, and DSM-5; and (2) the 2002 AAMR Manual, and 2010 AAIDD Manual — all have significant diagnostic features, explanations, and qualifiers for forensic use (many of which are discussed below when detailing each prong). The standards stress the importance of (1) clinical judgment, and (2) a comprehensive view that considers multiple sources of information. See, e.g., Def.’s Ex. 1016, AAIDD User’s Guide at 9 (“Clinical judgment is a special type of judgment rooted in a high level of clinical expertise and experience; it emerges directly from extensive data.”); Def.’s Ex. 1019, DSM-5 at 37 (“Clinical training and judgment are required to interpret test results and assess intellectual performance.”); Def.’s Ex. 1017, Excerpt from DSM-IV-TR re. Use of Clinical Judgment (“In addition to the need for clinical training and judgment, the method of data collection is also important. The valid application of the diagnostic criteria ... necessitates an evaluation that directly accesses the information contained in the criteria sets[.]”); Def.’s Ex. 1014, 2002 AAMR Manual at 66 (“The assessment of intellectual functioning must rely on sound procedures and may, at times, require information from multiple sources.”); Def.’s Ex. 1015, 2010 AAIDD Manual at 41 (same); Def.’s Ex. 1016, AAIDD User’s Guide at 7-8 (setting forth “best practices,” including “[rjecognizing the multifactorial nature of the etiology of [intellectual disability],” and “[u]sing a multidimensional approach to classification that is based on the specific purpose for classification and incorporates the factors that impact human functioning”); Thomas v. Allen, 614 F.Supp.2d 1257, 1283 (N.D.Ala.2009) (“[I]t is crucial that clinicians conduct a thorough social history and align data and data collection to the critical question(s) at hand.”), aff'd, 607 F.3d 749 (11th Cir.2010) (quoting a previous version of the AAIDD User’s Guide).

In this regard, various witnesses confirmed the importance of clinical judgment, and the use of multiple sources of information, in assessing a person’s intelligence and whether someone is intellectually disabled. See, e.g., Tr. Dec. 11, 2013 (Dr. James) at 45 (“[I]t’s [about] having additional information about the integrity of the neural system ... for whatever purpose it might be, whether it’s making a decision in an Atkins case or ... an intervention or treatment.”); id. at 69 (“[C]linical judgment is a place where you can consider other kinds of factors that might lead to a person’s cognitive impairment. ... As a clinician, you would be looking at all of these different sources of data, not just the IQ score but other data about adaptive functioning to understand that, and weigh ... different pieces of information.”); Tr. Dec. 16, 2013 (Dr. Woods) at 52 (emphasizing the relevance of clinical judgment with “all of the instruments with which we determine intellectual disability”); Tr. Dec. 12, 2013 (Dr. Boone) at 194 (“[I]t comes down to clinical judgment. If you have evidence that someone performed poorly in school, tested out poorly on standardized testing, then you would make the case that they were low functioning at that point in time.... It really comes down to the clinical judgment going through those records.”); id. at 208 (testifying that it is generally accepted practice for a neuropsychologist to “take the information that you get from testing instruments other than IQ tests and look at that in conjunction with what you’ve gotten in the IQ tests to see how an individual is performing cognitively”).

With these clinical standards firmly in mind, the court next details the relevant parameters of each of the three prongs.

3. Prong One: “Significantly Subav-erage Intellectual Functioning”

a. The relative importance of IQ scores

Psychologists and others in the clinical community consistently discuss human “intelligence” in terms of “g,” a general factor of intelligence. See, e.g., Def.’s Ex. 1015, 2010 AAIDD Manual at 34 (“[IJntellectual functioning ... is best conceptualized and captured by a general factor of intelligence (g).”). “Intelligence is a general mental ability. It includes reasoning, planning, solving problems, thinking abstractly, comprehending complex ideas, learning quickly, and learning from experience.” Id. at 31. And “[m]ost of the more commonly used individual tests of intelligence ... provide metrics of this g factor.” Id. at 32.

Although the DSM-5 “de-emphasizes IQ scores as determinants” of intellectual disability, Hernandez, 537 Fed.Appx. at 533 n. 1, it nevertheless remains accepted that “IQ tests are the best available tools for measuring intellectual functioning” such that “both the AAIDD and the APA frame prong one criteria in terms of IQ scores.” United States v. Salad, 959 F.Supp.2d 865, 870 (E.D.Va.2013). In this regard, the DSM-5 describes prong one in part as follows:

Intellectual functioning is typically measured with individually administered and psychometrically valid, comprehensive, culturally appropriate, psychomet-rically sound tests of intelligence. Individuals with intellectual disability have scores of approximately two standard deviations or more below the population mean, including a margin for measurement error (generally +5 points). On tests with a standard deviation of 15 and a mean of 100, this involves a score of 65-75 (70 ± 5). Clinical training and judgment are required to interpret test results and assess intellectual performance.

Def.’s Ex. 1019, DSM-5 at 37.

Likewise, the 2010 AAIDD Manual recognizes that “[a]lthough far from perfect, intellectual' functioning- is currently best represented by IQ scores when they are obtained from appropriate, standardized and individually administered assessment instruments." Def.'s Ex. 1015, 2010 AAIDD Manual at 31. Under this standard, "[t]he `significant limitations iii intellectual functioning' criterion for a diagnosis of intellectual disability is an IQ score that is approximately two standard deviations below the mean, considering the standard error of measurement for the specific instruments and the instruments' strengths and limitations." Id. The AAIDD emphasizes that "[t]he intent of this definition is not to specify a hard and fast cutoff point/score for meeting the sig-Tilficant limitations in intellectual functioning criteria of [intellectual disability]." Id. at 35. "The use of `approximately' reflects the role of clinical judgment in weighing the factors that contribute to the validity and precision of a decision. The term also addresses statistical error and uncertainty inherent in any assessment of human behavior." Id.

Thus, courts properly recognize that "[t]he psychiatric and psychological communities, including those specializing in the treatment of [intellectual disability], agree [that] `[a] fixed point cutoff score for [intellectual disability] is not psychomet-rically justifiable.'" Sasser, 735 F.3d at 843 (quoting 2010 AAIDD Manual at 40). "It is possible to diagnose [intellectual disability] in individuals with IQs between 70 and 75 who exhibit significant deficits in adaptive behavior because there is `a measurement error of approximately 5 points [in assessing IQ], depending on the testing instrument." Id. (quoting Jackson v. Norris, 615 F.3d 959, 965 n. 7 (8th Cir.2010) (in turn quoting DSM-IV-TR at 41-42)). "Conversely, [intellectual disability] would not be diagnosed in an individual with an IQ lower than 70 if there are no significant deficits or impairments in adaptive functioning." Def.'s Ex. 1020, DSM-IV-TR at 42. "Simply put, an IQ test score alone is inconclusive of `significantly subaverage general intellectual functioning.'" Sasser, 735 F.3d at 843 (emphasis added).

"The most widely-accepted IQ tests in the United States are the Wechsler Intelligence Scales, which include .. the Wech-sler Adult Intelligence Scale (`WAIS')." Wilson, 922 F.Supp.2d at 344. Another "widely recognized and utilized" IQ instrument is the Stanford-Binet Intelligence Scales ("SB"). Thomas, 607 F.3d at 753.

b. Measurement e~ors and confidence intervals

Clinical authorities also agree that "{a]ll IQ tests . . contain at least some possibility of error, making it impossible to state a test subject's `true' IQ score with certainty." Wilson, 922 F.Supp.2d at 345 (citing Thomas, 614 F.Supp.2d at 1269). "An IQ score is subject to variability as a function of a number of potential sources of error, including variations in test performance, examiner's behavior, cooperation of the test taker, and other personal and environmental factors." Def.'s Ex. 1015, 2010 AAIDD Manual at 36. And so, accepted IQ tests take into account a "standard error of measurement" ("SEM"), which "varies by test, subgroup, and age group," and "is used to quantify this variability and provide a stated statistical confidence interval within which the person's true score falls." Id. "The confidence interval refers to a percentage corresponding to [a] degree of confidence that an interval around the obtained IQ score contains the true IQ score." Wilson, 922 F.Supp.2d at 345 (citing Wiley v. Epps, 668 F.Supp.2d 848, 893-94 (N.D.Miss.2009)).

According to the AAIDD, “[f]or well-standardized measures of general intellectual functioning, the [SEM] is approximately 3 to 5 points.” Def.’s Ex. 1015, 2010 AAIDD Manual at 36. In terms of confidence intervals (with a normal curve), the AAIDD describes a 66% confidence interval as the range from one SEM below to one SEM above a given score (“scores of about 66 to 74”) and a 95% confidence interval as the range from two SEMs below to two SEMs above a given score (“scores of about 62 to 78”). Id. For example, “the 95% confidence interval for a given IQ score would show the range of scores within which we can be 95% confident that a person’s true IQ score falls.” Wilson, 922 F.Supp.2d at 345.

“Understanding and addressing [an IQ] test’s [SEM] is a critical consideration that must be part of any decision concerning a diagnosis of [intellectual disability.]” Def.’s Ex. 1015, 2010 AAIDD Manual at 36. And so “[b]oth [the] AAIDD and the [APA] support the best practice of reporting an IQ score with an associated confidence interval.” Id. “Reporting an IQ score with an associated confidence interval is a critical consideration underlying the appropriate use of intelligence tests and best practices; such reporting must be a part of any decision concerning the diagnosis of [intellectual disability].” Id.

The testimony at the hearings confirmed these clinical standards. See, e.g., Tr. Dec. 11, 2013 (Dr. James) at 56 (“[W]e always have to be thinking of [a] person’s IQ in terms of a range of scores, not as a single IQ score.... And that’s what’s reflected in the standard of error of measurement.”); Tr. Dec. 16, 2013 (Dr. Woods) at 41 (testifying that “the idea of being fixed by an IQ score is not appropriate” and opining based upon a range of scores “particularly when taking the confidence interval into consideration”).

Accordingly, the court will not consider Defendant’s various reported IQ scores in isolation — rather, the court will consider them as part of a range (above and below) in relation to the reported (if given) confidence interval and SEM. And the court does not apply a “hard and fast cutoff point/score for meeting the significant limitations in intellectual functioning” prong. Def.’s Ex. 1015, 2010 AAIDD Manual at 35. Rather, the court will look to a reported range of IQ scores, as part of a comprehensive analysis of all the relevant evidence for this prong (and the other prongs) of the clinical definition.

c. The “Flynn Effect”

The court will also consider the “Flynn Effect,” which is “a theory that IQ scores increase over time, so that a person who takes an IQ test that has not recently been ‘normed’ may have an artificially inflated IQ score.” Pizzuto, 729 F.3d at 1223 (citing James R. Flynn, Tethering the Elephant: Capital Cases, IQ, and the Flynn Effect, 12 Psychol. Pub. Pol’y & L. 170, 173 (2006)). “The standard practice is to deduct 0.3 IQ points per year (3 points per decade) to cover the period between the year the test was normed and the year in which the subject took the test.” Id.

The Flynn effect acknowledges that as an intelligence test ages, or moves farther from the date on which it was standardized, or normed, the mean score of the population as a whole on that assessment instrument increases, thereby artificially inflating the IQ scores of individual test subjects. Therefore, the IQ test scores must be recalibrated to keep all test subjects on a level playing field.

Thomas, 607 F.3d at 753. See Def.’s Ex. 1015, 2010 AAIDD Manual at 37 (“In cases where a test with aging norms is used, a correction for the age of the norms is warranted.”). By doing so, however, the court will consider both “Flynn-adjusted” and non-adjusted scores — the court will not automatically discard or ignore non-adjusted scores, but will keep all relevant data in mind in making its assessment.

d. The “practice effect”

Much testimony focused on a phenomenon called the “practice effect,” which clinical sources recommend taking into account. See id. at 35, 38, 102. Specifically, the AAIDD describes the practice effect as follows:

The practice effect refers to gains in IQ scores on tests of intelligence that result from a person being retested on the same instrument. Kaufman (1994) noted that practice effect can occur when the same individual is retested on a similar instrument. For example, the WAIS-III Manual presents data showing the artificial increase in IQ scores when the same instrument is readminis-tered within a short time interval. The WAIS-III Manual also reports average increases between administrations with intervals of 2 to 12 weeks. For this reason, established clinical practice is to avoid administering the same intelligence test within the same year to the same individual because it will often lead to an overestimate of the examinee’s true intelligence.

Id. at 38.

“The theory behind the practice effect ‘is that because IQ assessments rely upon novel tasks and instructions to assess ability and performance, an instruction given on a test will be more familiar to the examinee and more quickly implemented on subsequent presentations.’” Wilson, 922 F.Supp.2d at 352 (quoting Wiley, 668 F.Supp.2d at 896). In general, a practice effect is larger for a “performance IQ” as compared to a “verbal IQ” (both of which are components of a “full scale IQ” on some tests). See, e.g., Def.’s Ex. 1033, Alan S. Kaufman, excerpt from R.J. Stern-berg, 2 Encyclopedia of Human Intelligence 828 (1994) (“Kaufman (1994)”) at 2; Tr. Dec. 18, 2013 (Dr. Denney) at 168, 176; Tr. Dec. 11, 2013 (Dr. James) at 101 (acknowledging a greater practice effect for a “performance scale” than for “knowledge 'tasks” on an IQ test).

But, “[ujnlike with the Flynn Effect, there does not appear to be an accepted method in the psychological community for adjusting IQ scores to account for the practice effect.” Wilson, 922 F.Supp.2d at 352. For example, in rejecting a suggestion that an individual’s IQ scores should be adjusted downward by five to eight points for all retests because of a practice effect, Wilson emphasized that authorities state “only that ‘[clinicians should understand the average practice effect gains,” ’ and do “not recommend adjusting an individual’s IQ scores” for all retests. Id. at 352-53; see Def.’s Ex. 1033, Kaufman (1994) at 4 (“Clinicians should understand the average practice effect gains in intelligence scores[J”). Indeed, the AAIDD recommends that clinicians “avoid administering the same intelligence test within the same year to the same individual.]” Def.’s Ex. 1-15, 2010 AAIDD Manual at 38 (emphasis added).

In general, a practice effect depends upon the length of time between the original test and the retest. See, e.g., Def.’s Ex. 1033, Kaufman (1994) at 4 (indicating that a practice effect overestimates a person’s intellectual functioning “especially if the retest is given within about six months of the original test, or ... several times in the course of a few years”); Tr. Dec. 18, 2013 (Dr. Denney) at 47 (“Available research shows that the effect of practice enhancement of the score drops with time.... As you get further away, the increase drops each time.”); id. at 185-(“[I]t’s clear there’s more retest gain early on, but as time goes by we see the scores decreasing and decreasing.”). Several courts have recognized this proposition based on expert testimony. See, e.g., Wilson, 922 F.Supp.2d at 352; Blue v. Thaler, 2010 WL 8742423, at *13 (S.D.Tex. Aug. 19, 2010) (“[T]he practice effect only applies when there is a short interval between tests. The nine-month period here should have dispelled any lingering effect from the first test.”); Green v. Johnson, 2006 WL 3746138, at *44 (E.D.Va. Dec. 15, 2006) (“The practice effect refers to an increase in a person’s score on an IQ test when it is administered within a short time after taking the same or [a] similar test.... [T]he effect is more pronounced the closer in time the tests are given.”), Report and Recommendation Adopted as Modified, 2007 WL 951686 (E.D.Va. Mar. 26, 2007), aff'd, 515 F.3d 290 (4th Cir.2008).

And clinical sources (i.e., the 2010 AAIDD Manual and DSM-5) do not quantify such a practice effect, particularly for intervals over a year — -although some research or literature suggests that some type of a practice effect is possible over longer periods, and can result in “cumulative effects” or “progressive error” with repeated administration of intelligence tests. See, e.g., Def.’s Ex. 1033, Kaufman (1994) at 4; Tr. Dec. 11, 2013 (Dr. James) at 66-67. Moreover, the court accepts the testimony of Dr. Denney that, generally, a practice effect is more likely to occur with a more intelligent person with a higher IQ, than with a less intelligent person:

Q. (by the court): Is there any literature on the practice effect and intelligence, meaning the smarter your are, the more likely the practice effect would accelerate that difference in the scores versus someone [at] a lower end is less likely to see the same degree of practice effect?

A. Yes, there is. And that’s exactly what you see.[T]he band of IQs do not have the same complete practice effect, and what you’re going to see is a greater practice effect for the higher scores than the lower scores.

See Doc. No. 2264, Tr. Dec. 18, 2013 (Dr. Denney) at 50-51.

The court, having reviewed the evidence and considered caselaw and clinical sources, follows an approach similar to Wilson. “The court will — as clinicians recommend — take into account the practice effect in interpreting [Defendant’s] IQ scores.” Wilson, 922 F.Supp.2d at 353 (citing 2010 AAIDD Manual at 35, 38, 102). But the court will not apply any specific downward point adjustment to Defendant’s IQ scores because of a practice effect. And when considering a practice effect, “the court will be mindful that the practice effect diminishes significantly (although perhaps without disappearing entirely) as the length of time between test administrations increases.” Id. at 354 (citing Blue, 2010 WL 8742423, at *13). That is, the court will consider a possible practice effect as a factor, among others, in assessing the reliability or uncertainty of particular scores on particular tests. See Def.’s Ex. 1015, 2010 AAIDD Manual at 40 (“[I]n evaluating the role that an IQ score plays in making a diagnosis of ID, clinicians should ... (b) interpret the obtained score in reference to the test’s [SEM], the assessment instruments’ strengths and limitations, and other factors (such as practice effect, fatigue effects, and age or norms used) that determine the size of the error involved in estimating the person’s true score[J”).

4. Prong Two: “Adaptive Functioning”

“Adaptive functioning refers to how effectively individuals cope with common life demands and how well they meet the standards of personal independence expected of someone in their particular age group, sociocultural background, and community setting.” Salad, 959 F.Supp.2d at 877 (quoting DSM-IV-TR at 42). The DSM-5 articulates deficits in adaptive function as follows:

Deficits in adaptive functioning (Criterion B) refer to how well a person meets community standards of personal independence and social responsibility, in comparison to others of similar age and sociocultural background. Adaptive functioning involves adaptive reasoning in three domains: conceptual, social, and practical. The conceptual (academic) domain involves competence in memory, language, reading, writing, math reasoning, acquisition of practical knowledge, problem solving, and judgment in novel situations, among others. The social domain involves awareness of others’ thoughts, feelings, and experiences; empathy; interpersonal communication skills; friendship abilities; and social judgment, among others. The practical domain involves learning and self-management across life settings, including personal care, job responsibilities, money management, recreation, self-management of behavior, and school and work task organization, among others. Intellectual capacity, education, motivation, socialization, personality features, vocational opportunity, cultural experience, and coexisting general medical conditions or