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Dr. Frank Gresham APA2009 IQ assessment and Atkins death peanlty presentation


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This slide show was graciously made available for viewing here by Dr. Frank Gresham. They are the slides he presented as part of a "Symposium: Death Penalty Court Decisions and Mental Retardation Classification and Research,
Presented at the 2009 APA Annual Convention, August 7, 2009, Toronto, Ontario CANADA"

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Dr. Frank Gresham APA2009 IQ assessment and Atkins death peanlty presentation

  1. 1. Intellectual Assessment in Atkins Cases and Use of School Diagnoses Frank M. Gresham Louisiana State University Symposium: Death Penalty Court Decisions and Mental Retardation Classification and Research , Presented at the 2009 APA Annual Convention, August 7, 2009, Toronto, Ontario CANADA
  2. 2. Commonwealth of Virginia Virginia’s Definition of Mental Retardation <ul><li>A disability originating before age of 18 years characterized by: </li></ul><ul><ul><li>Significantly subaverage intellectual functioning as demonstrated by performance on a standardized measure of intellectual functioning that is at least 2 standard deviations below the mean </li></ul></ul><ul><ul><li>Significant limitations in adaptive behavior as expressed in conceptual, social, and practical adaptive skills </li></ul></ul><ul><ul><li>Assessment of intellectual functioning shall include administration of at least one standardized measure generally accepted by the field of psychological testing </li></ul></ul><ul><ul><li>With respect to intellectual functioning, the Virginia statute provides that “the Commissioner shall maintain an exclusive list of standardized measures of intellectual functioning generally accepted by the field of psychological testing” * </li></ul></ul>*Tests move on and off this list quite frequently
  3. 3. Ruling: U.S. District Court Eastern District of Virginia Walker v True <ul><li>Petitioner has failed to show by preponderance of evidence that he was mentally retarded before age of 18 </li></ul><ul><li>Petitioner has shown that he sufferers from below average mental intelligence </li></ul><ul><li>Petitioner has failed to show by preponderance of evidence that the scored 2 standard deviations below the mean on an approved measure of intellectual functioning </li></ul><ul><li>Only scores of 70 or less are considered 2 standard deviations below the mean </li></ul><ul><li>Petitioner argues that his WISC-R score of 76 and WAIS-III score of 80 are both 2 standard deviations below the mean in light of the standard error of measurement, practice effect, and Flynn Effect. </li></ul><ul><li>Court considered these explanations “speculative” </li></ul><ul><li>Decision overturned by Fourth Circuit Court of Appeals </li></ul>
  4. 4. Interpretive Issues in Intellectual Assessment <ul><li>Nature of Intellectual Functioning </li></ul><ul><li>Flynn Effect </li></ul><ul><li>Practice Effects </li></ul><ul><li>Measurement Error </li></ul><ul><li>School “Diagnoses” </li></ul>
  5. 5. Nature of Intelligence <ul><li>Fluid versus Crystallized Intelligence: Liquid or Mineral? </li></ul><ul><li>Walker’s IQ Data </li></ul><ul><li>Crystallized Intelligence </li></ul><ul><ul><li>Woodcock-Johnson-III (33 years) Verbal=78 </li></ul></ul><ul><ul><li>WISC-R (11-6 years) VIQ= 70 </li></ul></ul><ul><ul><li>WISC-R (14-9 years) VIQ= 75 </li></ul></ul><ul><ul><li>WAIS-III (26 years) VIQ= 87 * </li></ul></ul><ul><ul><li>WAIS-III (27 years) VIQ= 80 </li></ul></ul><ul><ul><li>Mdn = 78 </li></ul></ul><ul><li>Fluid Intelligence (33 years) </li></ul><ul><ul><li>CTONI-68 </li></ul></ul><ul><ul><li>Raven- 63 </li></ul></ul><ul><ul><li>GAMA- 61 </li></ul></ul><ul><ul><li>Mdn = 63 </li></ul></ul><ul><ul><li>*Scoring errors admitted in Court </li></ul></ul>
  6. 6. Flynn Effect <ul><li>Well-established finding of 0.3 point increase in mean IQ per year </li></ul><ul><li>Findings hold for U.S. and worldwide </li></ul><ul><li>Norms become less accurate over time </li></ul><ul><li>WAIS-III particularly susceptible to increase (normative problems) </li></ul><ul><li>Flynn’s Deposition in Walker case * </li></ul><ul><ul><li>WAIS-R (1978) & WAIS-III (1995) +5.24 points </li></ul></ul><ul><ul><li>WISC-III (1989) & WAIS-III (1995) +1.64 points </li></ul></ul><ul><ul><li>WAIS-III (1989) & SB-IV (2001) +3.16 points </li></ul></ul><ul><ul><li>WAIS-III (1989) & WISC-IV (2001) +0.76 points </li></ul></ul><ul><li>WAIS-III inflates scores compared to contemporarily normed tests </li></ul><ul><li>“ WAIS-III score of 79 (obtained in 2000) should be interpreted as a score of 75 (7 years X 0.3=2.10+2.34 WAIS-III adjustment.” * </li></ul>*Dates reflect when test was normed, not when it was released
  7. 7. Flynn Effect & MMR Diagnoses Kanaya, Scullin, & Ceci (2003) (Based on almost 9,000 referrals to SPED) <ul><li>Size of Flynn Effect in MMR –Borderline Range of IQ </li></ul><ul><ul><li>WISC-R-WISC-R: 79.0-80.2 </li></ul></ul><ul><ul><li>WISC-R-WISC-III: 78.4-73.9 </li></ul></ul><ul><ul><li>WISC-III-WISC-III: 78.5-78.1 </li></ul></ul><ul><ul><li>WISC-III-WISC-IV 78.5-74.5* </li></ul></ul><ul><li>Changes in MMR Classification Because of Flynn Effect </li></ul><ul><ul><li>Change from WISC-R to WISC-III almost DOUBLED rate of MMR classification (19% to 34%) </li></ul></ul><ul><li>Impact of Flynn Effect on Borderline IQ Ranges </li></ul><ul><ul><li>IQ 71-75 on WISC-R </li></ul></ul><ul><ul><li>3-fold increase in IQs 66-70 on when retested with WISC-III (14% to 40%) </li></ul></ul>*Not part of the Kanaya et al. (2003) study
  8. 8. Take Away Message on Flynn Effect <ul><li>Intelligence has not changed over time </li></ul><ul><li>Changes in measured IQ reflect creeping obsolescence of norms </li></ul><ul><li>Level of intelligence reflects accuracy of norms; not accuracy of IQ </li></ul><ul><li>IQ scores inextricably, directly, & entirely dependent on norms </li></ul><ul><li>Flynn Effect & absolute level of intelligence is empirically moot </li></ul><ul><li>Prosecutors may argue that IQ of 70 20 years ago would be IQ 76 today </li></ul><ul><li>Defense may argue that IQ of 71 today would be IQ 65 20 years from now </li></ul><ul><li>By logical extension, norms could become so tough that everyone would qualify as being mentally retarded </li></ul><ul><li>IQ scores must be interpreted in terms of when norms were collected </li></ul>
  9. 9. Practice Effects & IQ Test Scores <ul><li>Practice effects occur on IQ tests that are repeatedly administered (5-8 points) </li></ul><ul><li>Shorter the retest interval, the greater the practice effects </li></ul><ul><li>Low initial scores on a test tend to increase on retest </li></ul><ul><li>Differences difficult to interpret when initial test & retest measures are different </li></ul><ul><li>Differences in results may depend on item content in the test </li></ul><ul><li>Differences between repeated testing results may be due to differences in motivation, interest, or the “stakes” of testing </li></ul><ul><li>“ Petitioner has failed to present evidence that an adjustment in test scores due to practice effects would be anything other than speculation.” </li></ul><ul><li>Experts have not made courts understand that practice effects are real, not speculative, particularly in death penalty cases where defendants are repeatedly tested </li></ul>
  10. 10. Role of Measurement Error <ul><li>What is the most appropriate estimate of error in death penalty cases? </li></ul><ul><ul><li>Internal consistency estimates? </li></ul></ul><ul><ul><li>Stability estimates? </li></ul></ul><ul><ul><li>Both? </li></ul></ul><ul><li>Consistency estimates typically yield less measurement error </li></ul><ul><li>Consistency: How reliable is this individual’s score on an IQ test on a given day? </li></ul><ul><li>Stability: Will this individual will obtain a similar score if retested with the same test in the future? </li></ul><ul><li>Fourth Circuit refused to use the standard error of measurement to lower IQ scores in Atkins cases due to the “inherent speculation of using the standard error of measurement to lower an IQ score when it could just as likely be used to raise an IQ score.” </li></ul><ul><li>Experts have not made courts understand band of error concept & probability of true score </li></ul>State’s expert refers consistently in his report to the “standard error of measure” (sic)
  11. 11. School Diagnoses: Some Atkins Case Examples <ul><li>Daryl Atkins-Virginia </li></ul><ul><ul><li>IQ=59 </li></ul></ul><ul><ul><li>Not diagnosed as MR in school </li></ul></ul><ul><ul><li>Long, pervasive history of academic underachievement </li></ul></ul><ul><li>Kevin Green-Virginia </li></ul><ul><ul><li>IQ=71 </li></ul></ul><ul><ul><li>Not diagnosed as MR by schools </li></ul></ul><ul><ul><li>Diagnosed as speech/language impaired by D.C. schools </li></ul></ul><ul><ul><li>Retained 3 times in school </li></ul></ul><ul><ul><li>Referred to SPED at age 13 years </li></ul></ul><ul><ul><li>Long, pervasive history of academic underachievement </li></ul></ul><ul><ul><li>EXECUTED </li></ul></ul><ul><li>Darick Walker-Virginia </li></ul><ul><ul><li>IQ=63-78 </li></ul></ul><ul><ul><li>Not diagnosed as MR by schools </li></ul></ul><ul><ul><li>Diagnosed has specific learning disability (SLD), later ED </li></ul></ul><ul><ul><li>Lost in U.S. District Court, appealed to U.S. Court of Appeals (won) </li></ul></ul>
  12. 12. School Diagnoses (continued) <ul><li>Johnny L. Neal -Alabama </li></ul><ul><ul><li>IQ=65 </li></ul></ul><ul><ul><li>Not diagnosed as MR by schools (attended Louisiana schools) </li></ul></ul><ul><ul><li>Diagnosed as “Low Borderline” by schools </li></ul></ul><ul><ul><li>Director of SPED testified that schools did not use MR label except in cases of severe MR </li></ul></ul><ul><ul><li>Admitted to Hammond State School for the Mentally Retarded (MR diagnosis) </li></ul></ul><ul><ul><li>Admitted to East State Hospital (2 suicide attempts + MR) </li></ul></ul><ul><ul><li>Death sentence commuted to life imprisonment without parole </li></ul></ul>
  13. 13. School “Diagnoses” <ul><li>All 4 cases never had diagnosis of mental retardation by schools </li></ul><ul><li>Prosecutors often take this as prima facie evidence that MR was not exhibited during developmental period (prior to age 18) </li></ul><ul><li>Most cases have a specific learning disability diagnosis which courts view as not MR </li></ul><ul><li>Schools reluctant, if not totally unwilling, to assign MR label for MMR, particularly for African-American individuals </li></ul>
  14. 14. IQ<75 MacMillan, Gresham, Siperstein, & Bocian (1996) SLD 44% M =68 MR 14% M =63 The labyrinth of IDEA: School decisions for referred students with subaverage general intelligence. American Journal on Mental Retardation, 101, 161-174.
  15. 15. IQ<70 Kanaya et al. (2003) SLD 48.1% MR 48.5% M =64 M =66
  16. 16. Summary of School “Diagnoses” <ul><li>Schools use the SLD label as a catchall category for SPED services </li></ul><ul><li>Students with MMR 3 times more likely to be classified as SLD </li></ul><ul><li>Students with MMR also more likely to be classified as SLI </li></ul><ul><li>Students with MMR just as likely to be deemed ineligible as MMR </li></ul><ul><li>All Atkins cases are adults & school history becomes critical (onset prior to age 18 years) </li></ul><ul><li>Courts don’t “get” schools & SPED process </li></ul>
  17. 17. What’s the Take Away Message? <ul><li>Courts do not understand the nature of intelligence and how an individual might obtain different scores on different tests at different times </li></ul><ul><li>Psychometric True Score (IQ) vs. Absolute True Score (DNA) </li></ul><ul><li>Courts consider the Flynn Effect to be a theory rather than fact </li></ul><ul><li>Courts consider practice effects to be speculative rather than fact </li></ul><ul><li>Courts do not understand concept of measurement error & regression artifacts </li></ul><ul><li>Courts often take failure of schools to diagnose defendants as MR to indicate absence of MR </li></ul><ul><li>COURTS JUST DON’T UNDERSTAND THE CONCEPT OF MMR AND THE “CLOAK OF COMPETENCE” </li></ul><ul><li>Psychological evidence in these cases often not be very convincing </li></ul>