Seemingly Anomalous WISC-IV Full Scale IQ Scores in the American and Canadian Standardization Samples

The American and Canadian standardization samples for the fourth edition of the Wechsler Intelligence Scale for Children were used to ascertain the prevalence of “seemingly anomalous” Full Scale IQ (FSIQ) scores for all possible sums of scaled scores combinations of the Verbal Comprehension Index, Perceptual Reasoning Index, Working Memory Index, and Processing Speed Index. About 1% of FSIQ scores in both samples were anomalous (that is, fell outside the range of the four indices). Interestingly, the prevalence of anomalous scores was higher at the extremes of the FSIQ distribution. Moreover, anomalous FSIQ scores occurring above or below the mean of the FSIQ distribution (that is, 100) were larger or smaller, respectively, than any of the four indices. Furthermore, if the range of the four indices did contain the FSIQ (the non-anomalous case), when the FSIQ was below or above 100 it tended to be located distally in the half-segment of the range furthest below or above 100, respectively. A non-technical intuitive analogy from Olympic sports and a statistical explanation for the findings are provided. Important implications for practitioners are also presented. Portions of this paper were presented March 17, 2006 at the 20th annual Joseph R. Royce Research Conference, Department of Psychology, University of Alberta, Edmonton, Alberta.     

Seemingly anomalous full scale IQ scores on the WAIS-III and the WISC-III

The Canadian and American WISC-III and the American WAIS-III standardization data were used to investigate the prevalence of “seemingly anomalous” Full Scale IQ (FSIQ) scores for all possible Verbal and Performance sums of scale score combinations. It was found that 6% of FSIQ scores in these three samples were seemingly anomalous (i.e., fell outside of their associated VIQ/PIQ intervals). Interestingly, the anomalous FSIQ scores were more prevalent at the extremes of the FSIQ distribution, and did not occur when the VIQ/PIQ interval was greater than 12. Additionally, anomalous FSIQ scores were generally further from the center of the FSIQ distribution than were the associated VIQ and PIQ scores. Also, when the VIQ/PIQ interval contained FSIQ (the non-anomalous case), FSIQ tended to be located distally in the half-segment of the VIQ/PIQ interval furthest from the center of the FSIQ distribution. A statistical explanation for the findings is provided. Portions of this paper were presented March 3, 2000 at the 14th Annual Joseph R. Royce Research Conference, Department of Psychology, University of Alberta, Edmonton, Alberta. An erratum to this article is available at .     

Seemingly anomalous full scale IQ scores on the WAIS-III and the WISC-III

The Canadian and American WISC-III and the American WAIS-III standardization data were used to investigate the prevalence of “seemingly anomalous” Full Scale IQ (FSIQ) scores for all possible Verbal and Performance sums of scale score combinations. It was found that 6% of FSIQ scores in these three samples were seemingly anomalous (i.e., fell outside of their associated VIQ/PIQ intervals). Interestingly, the anomalous FSIQ scores were more prevalent at the extremes of the FSIQ distribution, and did not occur when the VIQ/PIQ interval was greater than 12. Additionally, anomalous FSIQ scores were generally further from the center of the FSIQ distribution than were the associated VIQ and PIQ scores. Also, when the VIQ/PIQ interval contained FSIQ (the non-anomalous case), FSIQ tended to be located distally in the half-segment of the VIQ/PIQ interval furthest from the center of the FSIQ distribution. A statistical explanation for the findings is provided. Portions of this paper were presented March 3, 2000 at the 14th Annual Joseph R. Royce Research Conference, Department of Psychology, University of Alberta, Edmonton, Alberta. An erratum to this article is available at .     

Comparison of Tetradic WAIS-III Short Forms in Predicting Full Scale IQ Scores in Neuropsychiatric Clinic Settings

Patients from two neuropsychology clinics (n = 283) were divided into model development (n = 189) and validation samples (n = 94) with proportional representation from each clinic. Three regression based models of four WAIS-III subtests were developed and cross-validated to evaluate their FSIQ estimation accuracy: (1) an optimized stepwise regression model derived from the development sample (Comprehension, Matrix Reasoning, Similarities, and Picture Arrangement), (2) an a priori WASI based model (Similarities, Matrix Reasoning, Vocabulary, and Block Design), and (3) an a priori model with relatively rapidly administered subtests from each Index Score factor of the WAIS-III (Information, Picture Completion, Arithmetic, and Digit Symbol-Coding). The models produced good (92 to 97%) FSIQ estimation accuracy within 10 points of FSIQ with none of these models performing significantly better than another. The utility of clinical use of short form FSIQ estimation is a function of accuracy needed versus administration time reduction and ease for the patient.     

Dyadic short forms of the Wechsler Adult Intelligence Scale-III

Various short forms of the Wechsler Adult Intelligence Scale (WAIS)/WAIS-R have been developed to obtain estimates of overall intellectual level, although little research of WAIS-III short forms has been published to date. Full Scale IQ (FSIQ) estimatesfromfour WAIS-III dyadic short forms were obtained by entering selected subtest scores from a mixed neurologic/ psychiatric sample (n = 196) into regression equations. Results were cross validated on a second sample (n = 57). Within both samples, WAIS-III FSIQ scores were highly correlated (r = .90-.92, p < .001) with estimated FSIQ scores. Estimated FSIQ fell within 5 points of actual FSIQ in 49% to 74% of cross-validation cases and within 10 points of actual FSIQ in 81% to 93% of the sample. Comparable to findings from previous short-form investigations, actual and estimated FSIQ classification levels agreed in 46% to 67% of cases in the cross-validation sample. These dyadic WAIS-III forms appear appropriate for obtaining gross estimates of FSIQ in similar populations, although caution is recommended in interpreting estimated IQ scores.     

Expanding the ecological validity of WAIS-IV and WMS-IV with the Texas functional living scale

Assessment of functional status is an important aspect of clinical evaluation. As part of the standardization of the Wechsler Adult Intelligence Scale-Fourth Edition (WAIS-IV) and Wechsler Memory Scale-Fourth Edition (WMS-IV), participants completed the Texas Functional Living Scale (TFLS), a measure of Instrumental Activities of Daily Living. The relationships between TFLS and WAIS-IV and WMS-IV were examined in both normally developing and clinical samples. In general, the highest correlations were between TFLS and measures of general cognitive ability (WAIS-IV FSIQ [Full Scale IQ] and GAI [General Ability Index]) and working memory (WAIS-IV WMI [Working Memory Index] and WMS-IV VWMI [Visual Working Memory Index]). Across the clinical populations, working memory subtests were generally strongly related to TFLS performance, although this relationship was more consistent with WAIS-IV than WMS-IV. Contrast scaled scores are presented for the TFLS based on WAIS-IV or WMS-IV performance. These scores allow the evaluation of functional abilities within the context of cognitive and memory ability, enhancing and expanding the utility of the WAIS-IV and WMS-IV.     

WISC-IV GAI and CPI profiles in healthy children and children with learning disabilities

IntroductionIn addition to the FSIQ, the General Ability Index (GAI) and the Cognitive Proficiency Index (CPI) are two ancillary scores that can be calculated for the Wechsler Intelligence Scale. The GAI and the CPI have been proposed to assist in identifying cognitive strengths and weaknesses, and thus to provide different views into individual's cognitive abilities.ObjectiveThe purpose of the present study is to provide the frequency of GAI/CPI score difference by direction, the frequency of FSIQ/GAI score difference, and the frequency of FSIQ/CPI score difference, for the French Wechsler Intelligence Scale for Children and Adolescents–Fourth Edition (WISC-IV).MethodThese frequencies are provided for a sample of healthy children (n = 483), and for a sample of children with learning disabilities (LD, n = 370). The GAI comprises verbal comprehension and perceptual reasoning subtests, while CPI comprises working memory and processing speed subtests.ResultsResults indicated that the healthy sample performed better than the LD sample for all composite scores. The FSIQ was lower than the GAI for both groups and this difference was slightly larger for the LD sample (−1.35 points vs. −3.22 points). The GAI was higher than the CPI for both samples, but this difference was not significantly larger for the LD sample (4.2 points vs. 6.16 points). Finally, while the FSIQ was higher than the CPI for both groups, this difference was not larger for the LD sample (2.85 points vs. 2.95 points).ConclusionThese findings support the use of the GAI and the CPI, in addition to the FSIQ.     

Indice d’aptitude général pour le WISC-IV : normes francophones

The Wechsler Children Intelligence Scale–Fourth Edition (WISC-IV, 2005) allows to calculate the FSIQ and four index scores: verbal comprehension, perceptual reasoning, working memory, and processing speed. In 1998, Prifitera and colleagues recommended to calculate the General Ability Index (GAI), as an alternative composite score. This score is based on Verbal Comprehension and Perceptual Reasoning only. The objective of the first study presented in this paper is to provide the GAI normative tables for the French WISC-IV; these tables were created using a statistical approximation procedure. The objective of the second study is to test the validity of these tables with data obtained from 60 children. Correlation between FSIQ and GAI is 0.91 and the relative mean difference is only 0.18 point. These tables, for the French version of the WISC-IV, allow using the GAI as an alternative measure of general ability.     

Identification of mental retardation by the system of multicultural pluralistic assessment: Nondiscriminatory or nonexistent?

The effects of applying the dual-criterion classification system for mental retardation in connection with the System of Multicultural Pluralistic Assessment (SOMPA) were investigated by using the SOMPA standardization sample as subjects. Average scaled scores on the Adaptive Behavior Inventory for Children (ABIC) were paired (a) with Full Scale IQ (FSIQ) Wechsler Intelligence Scale for Children-Revised or (b) with the SOMPA-derived Estimated Learning Potential (ELP). The children performing below the third percentile on either combination of measures were thus classified as “mentally retarded.” By the FSIQ and ELP procedures, 0.6% and 0.2%, respectively, of the children were so classified; the overwhelming majority of the children were of minority background. The implications for the diagnostic category of mild mental retardation and the further use of the SOMPA are discussed.     

Meta-Analysis of Intelligence Quotient (IQ) in Obsessive-Compulsive Disorder

Obsessive compulsive disorder (OCD) is associated with a moderate degree of underperformance on cognitive tests, including deficient processing speed. However, despite little research focusing on Intelligence Quotient (IQ) in OCD, it has long been speculated that the disorder is associated with elevated intellectual capacity. The present meta-analytic study was, therefore, conducted to quantitatively summarize the literature on IQ in OCD systematically. We identified 98 studies containing IQ data among individuals with OCD and non-psychiatric comparison groups, and computed 108 effect sizes for Verbal IQ (VIQ, n = 55), Performance IQ (PIQ, n = 13), and Full Scale IQ (FSIQ, n = 40). Across studies, small effect sizes were found for FSIQ and VIQ, and a moderate effect size for PIQ, exemplifying reduced IQ in OCD. However, mean IQ scores across OCD samples were in the normative range. Moderator analyses revealed no significant moderating effect across clinical and demographic indices. We conclude that, although lower than controls, OCD is associated with normative FSIQ and VIQ, and relatively lowered PIQ. These results are discussed in light of neuropsychological research in OCD, and particularly the putative impact of reduced processing speed in this population. Recommendations for utilization of IQ tests in OCD, and directions for future studies are offered.     

Long-term stability of the French WISC-IV: Standard and CHC index scores

Introduction

The assumption of the stability of intelligence is the source of the predictive value of the Intelligence Quotient (e.g., Full Scale IQ). However, few studies have investigated the long-term stability of one of the most frequently used tests in the field of cognitive assessment: the Wechsler Intelligence Scale for Children – 4th edition (WISC-IV).

The validity of the general ability measure for adults: comparison with WAIS-R IQ scores in a sample of college students with academic difficulties

The present study investigated the validity of the General Ability Measure for Adults (GAMA) by comparing it to the WAIS-R using a sample of 80 college students reporting learning difficulties. Results indicated that the mean GAMA IQ score did not deviate significantly from the mean WAIS-R IQ scores. The GAMA Full Scale IQ correlated significantly with the WAIS-R PIQ, VIQ, and FSIQ scores. However, the obtained correlation coefficient for the GAMA and WAIS-R PIQ significantly differed from the observed correlation coefficient between the GAMA and WAIS-R VIQ, suggesting that the GAMA was more clearly associated with perceptual skills than verbal abilities. When the correlation coefficients between the GAMA and WAIS-R scores were corrected for the effects of range restriction, the correlation coefficients increased, yet demonstrated the same pattern (e.g., GAMA/PIQ,.69; GAMA/VIQ,.36; GAMA/FSIQ,.60). The GAMA s accuracy in predicting individual student performance on the WAIS-R FSIQ also was examined.     

A Study of the Multiple and Complex Needs of Australian Young Adult Offenders

Youth offending is an important issue; it has significant social, psychological, interpersonal, and financial impacts on the society. International research has shown that young offenders generally have multiple and complex needs across a wide range of domains; however, research examining the depth and breadth of difficulties faced by young offenders in Australia is lacking. Arguably, such information is critical to help guide the development of valid preventative and treatment initiatives. This article describes a study examining the prevalence of mental illness, low intelligence, psychopathy, risk for reoffending, and criminogenic needs in 75 youth and young adult offenders in Victoria, Australia. Results suggest that the prevalence of mental illness and low intelligence is high in this population. Most (86%) of the sample had likely Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, Text Revision Axis I disorders (including mood, anxiety, substance use, eating, and psychotic disorders); 15% had a Full Scale Intellectual Quotient (FSIQ) below 70; and an additional 25.7% had an FSIQ in the borderline range. The majority (80%) of the sample was considered to be at a high or very high risk of reoffending. The high prevalence of mental health issues found in this population highlights the need for comprehensive and multifaceted assessment, and for psychosocial treatment and management to be comprehensive, addressing clinical, criminogenic, and social domains.     

Child abuse and neglect: Effects on Bayley Scale Scores

Compared to controls, children who were diagnosed as victims of Nonaccidental Trauma or Failure to Thrive had depressed Bayley Scale Mental Index scores, p < .002and p < .0001, respecitvely. Failure-to-Thrive children also had depressed Bayley Scale Motor Index scores, p < .0001. Nonaccidental-Trauma children had Mental and Motor Scale range scores, as determined by differences between basal and ceiling items on the Mental and Motor scales, that were a function of measured Mental and Motor Index Scores. Specifically, Nonaccidental-Trauma children with lower Mental Index scores had higher Mental Scale range scores than Nonaccidental-Trauma children with higher Mental Index scores, p < .003. Control children had Mental Scale range scores that did not differ between the high-low Mental Index score conditions. On the Motor Scale, range scores of Nonaccidental-Trauma children in the highlow Motor Index score conditions did not differ. However, children with higher Motor Index scores had higher Motor Scale range scores than control children with lower Motor Index scores, p < .02. In addition, the Infant Behavior Record of the Bayley Scales revealed behavior ratings of Nonaccidental-Trauma and Failure-to-Thrive children that differed from Mental and Motor Scale scores on several dimensions. These differences may reflect differential effects of the Nonaccidental-Trauma and Failureto-Thrive conditions.This study was supported in part by Department of Health, Education and Welfare, Office of Child Development Grant OCD-CB-371. We wish to acknowledge the advice and encouragement of Roger V. Cadol, director, Developmental Evaluation Center of Denver General Hospital, and Michael J. Fitch, director, Child Study Project. A portion of this article was read at the American Association on Mental Deficiency Region IV Conference, Albuquerque, New Mexico, October 2, 1975.     

Criterion-related bias with the guide to the assessment of test-session behavior for the WISC-III and WIAT: Possible race/ethnicity, gender, and SES effects

Using the Guide to the Assessment of Test-Session Behavior for the WISC-III and WIAT (GATSB), Anglo examiners recorded test observations for 969 children between the ages of 6 and 16 years. The children came from the standardization and validity-study samples of GATSB ratings completed with the Wechsler Intelligence Scale-Third Edition (WISC-III) (Wechsler, 1991). The sample differed by race (Anglo, black, Latino), socioeconomic status (SES) (high, middle, low), and gender. GATSB ratings and WISC-III Verbal, Performance, and Full Scale IQs were compared. Correlations between the GATSB and WISC-III were generally moderate (average R = -.27). Children who exhibited higher levels of avoidance, inattentiveness, and uncooperative behaviors while being tested tended to exhibit lower WISC-III scores. This pattern held true for Anglos, blacks, and Latinos; for girls and boys; and for those from high-, middle-, and low-SES homes. Evidence was generally absent that Anglo examiners display bias in black-Anglo, gender, or SES comparisons. However, consistent differences were noted between Latino and Anglo children. Examiners tended to rate Latinos as displaying better test behaviors than Anglos when children's IQs were below average, but comparable when IQs were average and above. Thus, the GATSB generally displayed similar intrasession validities for children who differ by race/ethnicity, gender, and SES.     

Validity of the Wechsler abbreviated scale of intelligence and other very short forms of estimating intellectual functioning

Performance on the Wechsler Adult Intelligence Scale-III (WAIS-III) was compared to performance on the Wechsler Abbreviated Scale of Intelligence (WASI), as well as short form estimations of intellectual functioning derived from WAIS-III performance, in a mixed clinical sample of 72 participants. The WASI verbal IQ (VIQ) score was significantly higher than the WAIS-III VIQ, whereas performance IQ (PIQ) estimates all differed from actual WAIS-III PIQ and full scale IQ (FSIQ). Correlations of WAIS-III scores with WASI scores were consistently lower than were correlations between the WASI-III and all other short forms. Although maintaining administration times of 15 minutesfor a two-subtest FSIQ and 30 minutes for a four-subtest FSIQ, the WASI did not consistently demonstrate desirable accuracy in predicting scores obtained from the WAIS-III. The results suggest that clinicians should use the WASI cautiously if at all, especially when accurate estimates of individuals' WAIS-III results are needed.     

Correlates of intellectual ability with morphology of the hippocampus and amygdala in healthy adults

Several prior imaging studies of healthy adults have correlated volumes of the hippocampus and amygdala with measures of general intelligence (IQ), with variable results. In this study, we assessed correlations between volumes of the hippocampus and amygdala and full-scale IQ scores (FSIQ) using a method of image analysis that permits detailed regional mapping of this correlation throughout the surface contour of these brain structures. We delineated the hippocampus and amygdala in high-resolution magnetic resonance images of the brain from 34 healthy individuals. We then correlated FSIQ with overall volumes and with the surface morphologies of each of these structures. Hippocampus volumes correlated significantly and inversely with FSIQ independently of gender, age, socioeconomic status, and whole brain volume. Left and right hippocampus volumes correlated respectively with verbal and performance IQ subscales. Higher IQs were significantly associated with large inward deformations of the surface of the anterior hippocampus bilaterally. These findings suggest that a smaller anterior hippocampus contributes to an increased efficiency of neural processing that subserves overall intelligence.     

Scoring reliability on the Wechsler Adult Intelligence Scale-Third Edition (WAIS-III)

Nineteen psychologists and 19 graduate students scored two Wechsler Adult Intelligence Scale-Third Edition patient protocols. Mean IQs and indexes were similar across groups, but the ranges for Verbal IQ (VIQ), Performance IQ (PIQ), and Full Scale IQ (FSIQ) on one protocol were 25, 22, and 11 points, respectively. For both protocols taken together, percentages of agreement with the "actual" IQs for psychologists were only 26.3 for VIQ, 36.8 for PIQ, and 42.1 for FSIQ. For students, percentages were 15.8 for VIQ, 23.7 for PIQ, and 31.6 for FSIQ. The percentages of FSIQs that fell within +/- 1 standard error of measurement of the actual IQs were 89.5 for psychologists and 76.3 for students. Scoring error also had a negative impact on index scores. Both groups were confident about their scoring accuracy.     

Effects on WAIS-III performance IQ (PIQ) and full scale IQ (FSIQ) when object assembly is substituted for each standard performance scale subtest

According to the WAIS-III Administration and Scoring Manual, Object Assembly (OA) may be substituted for any spoiled Performance subtest. This assertion has not been evaluated in a clinical sample. The present investigation reports differences that resulted in Performance IQ (PIQ) and Full Scale IQ (FSIQ) when OA replaced each of the Performance subtests. Participants were 47 referrals for neuropsychological assessment (age M = 45.98 years, SD = 9.82; education M = 13.82 years, SD = 2.78). Results indicated that OA may replace any Performance subtest without seriously altering the summary scores. Differences between the standard IQs and OA-based composites were < 2 points for PIQ and < 1 point for FSIQ. More than 90% of the OA-based composites fell within the 90% confidence limits of the corresponding IQ.     

Personality and intelligence as predictors of creativity

Participants completed the Big Five NEO-FFI (Costa & McCrae, 1992) as a personality measure, the Wonderlic Personnel Test (Wonderlic, 1992) as an intelligence measure, and four measures of creativity: Guilford’s (1967) unusual uses divergent thinking test; the Biographical Inventory of Creative Behaviours; a self-rated measure of creativity; and the Barron–Welsh Art Scale to measure creative judgement. Extraversion was significantly related to all four measures of creativity. Intelligence failed to add any incremental variance in predicting the creativity scores. Multiple regression indicated that up to 47% of the variance in divergent thinking scores can be accounted for by the Big Five personality traits. Personality correlates to creativity vary as a function of the creativity measure.