WISC-IV and WISC-III profiles in children with ADHD

Wechsler Intelligence Scale for Children, 3rd and 4th editions (WISC-III n = 586 and WISC-IV n = 118), profiles were compared for children with ADHD and normal intelligence. Mean Verbal Comprehension Index (VCI) and Perceptual Organization/Perceptual Reasoning Index (POI/PRI) scores were significantly higher than Freedom From Distractibility/Working Memory Index (FDI/WMI) and Processing Speed Index (PSI), and Symbol Search was higher than Coding. FDI/WMI and PSI scores were similar on both tests, but VCI and POI/PRI were higher on the WISC-IV than on the WISC-III. Therefore, index discrepancies were greater for the WISC-IV, suggesting that the WISC-IV might be better than the WISC-III in delineating the strengths and weaknesses of children with ADHD. All children in the WISC-IV sample scored lowest on WMI or PSI, whereas only 88% of the WISC-III children scored lowest on FDI or PSI. Thus, the WISC-IV may be more helpful in diagnosing ADHD than the WISC-III.     

Two-subtest estimations of WAIS-III factor index scores

The reliability and validity of various short forms of the Wechsler Adult Intelligence Scale-Third Edition (WAIS-III; D. Wechsler, 1997) were evaluated in a sample of 100 patients with traumatic brain injury and in a demographically matched subgroup from the standardization sample. All short forms were based on 2-subtest estimations of the respective factor indexes. Although acceptable estimates could be obtained from all short forms for Verbal Comprehension, none of the possible short forms for Perceptual Organization consistently met the minimum criterion regarding the percentage of cases that fell within the 90% confidence interval of the full-length index. It is concluded that short-form estimates of the WAIS-III are not appropriate for clinical use when the goal is to obtain factor indexes.     

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.     

Development of an eight-subtest short form of the WISC-IV and evaluation of its clinical utility in children with traumatic brain injury

This study evaluated the degree to which an 8-subtest short form of the Wechsler Intelligence Scale for Children—Fourth Edition would yield acceptable estimates of the long-form Full-Scale IQ index while clarifying the underlying factor structure in a sample of 100 children and adolescents with traumatic brain injury. The short-form Full-Scale IQ had sufficient (i.e., at least two thirds) nonerror covariance with its full-length counterpart. In addition, a sufficient proportion (i.e., > 80%) of these short-form estimates fell within the 90% confidence interval of the respective full-length scores. Importantly, the elimination of 2 subtests, and in particular the Picture Concepts subtest, resulted in a factor structure where each remaining subtest was fairly specifically associated with its intended scale. It is concluded that this short form can be used clinically in children with traumatic brain injury without sacrificing reliability and with more straightforward interpretability at the level of the factor index scores.     

Use of population-specific parameters in generating WAIS-R short forms

One method of increasing the validity of WAIS-R short forms in estimating the standard WAIS-R Full Scale IQ is by using population-specific parameters in generating WAIS-R short forms. Three studies were conducted to evaluate (1) the contribution of age-scaled scores in generating accurate short-form Full Scale IQ, (2) the psychometric properties (validity and reliability) of WAIS-R subtests with a heterogeneous psychiatric population and subsequent development of short forms based on these properties, and (3) the validity of these short forms with respect to Silverstein's (1982) and Cyr and Brooker's (1984) 2- and 4-subtest combinations. Analyses showed (1) the use of age-scaled scores did not increase validity, (2) different subtest combinations were generated based on the population-specific parameters, and (3) increases in validity occurred for some short forms derived from the clinical sample. Despite increases in validity, clinicians and researchers are cautioned about the use of short forms in clinical practice.     

Graduate student WAIS-III scoring accuracy is a function of full scale IQ and complexity of examiner tasks

Research on the Wechsler Adult Intelligence Scale-Revised and Wechsler Adult Intelligence Scale-Third Edition (WAIS-III) suggests that practicing clinical psychologists and graduate students make item-level scoring errors that affect IQ, index, and subtest scores. Studies have been limited in that Full-Scale IQ (FSIQ) and examiner administration, recording, and scoring tasks have not been systematically varied. In this study, graduate student participants score a high (FSIQ = 112) and low (FSIQ = 85) IQ record form in one of two stimulus conditions: digitized film clips (N = 13) or partially completed record forms (N = 11). Results demonstrate that examiners are less accurate in the high IQ condition, and that recording examinee responses from scoring video clips results in more scoring errors. Obtained FSIQs are significantly higher than criterion IQ scores in the high IQ condition (8.46 for video condition, 2.55 for record form condition). Self-reported proficiency in WAIS-III administration and scoring is positively related to number of scoring errors.     

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.     

Orthogonal higher order structure and confirmatory factor analysis of the French Wechsler Adult Intelligence Scale (WAIS-III)

According to the most widely accepted Cattell-Horn-Carroll (CHC) model of intelligence measurement, each subtest score of the Wechsler Intelligence Scale for Adults (3rd ed.; WAIS-III) should reflect both 1st- and 2nd-order factors (i.e., 4 or 5 broad abilities and 1 general factor). To disentangle the contribution of each factor, we applied a Schmid-Leiman orthogonalization transformation (SLT) to the standardization data published in the French technical manual for the WAIS-III. Results showed that the general factor accounted for 63% of the common variance and that the specific contributions of the 1st-order factors were weak (4.7%-15.9%). We also addressed this issue by using confirmatory factor analysis. Results indicated that the bifactor model (with 1st-order group and general factors) better fit the data than did the traditional higher order structure. Models based on the CHC framework were also tested. Results indicated that a higher order CHC model showed a better fit than did the classical 4-factor model; however, the WAIS bifactor structure was the most adequate. We recommend that users do not discount the Full Scale IQ when interpreting the index scores of the WAIS-III because the general factor accounts for the bulk of the common variance in the French WAIS-III. The 4 index scores cannot be considered to reflect only broad ability because they include a strong contribution of the general factor.     

Need for achievement and performance on measures of behavioral fluency.

This investigation was designed to assess the relationship between a validated personality characteristic, need for achievement (nAch), and performance on measures of behavioral fluency. To infer this relationship, 50 neurologically intact college undergraduates were administered a questionnaire assessing nAch and a battery of tests including a short form of the WAIS and measures of behavioral fluency (i.e., verbal fluency). Statistical analysis indicated that subjects high on nAch obtained higher scores than subjects low on nAch on the measures of figural fluency and the WAIS Verbal Scale. No significant difference on verbal fluency was seen between the two groups. Secondly, the group high on nAch also had a higher mean Verbal IQ but not a higher mean Performance IQ as measured by a short form of the WAIS than did subjects scoring low on nAch.     

Étude exploratoire de la stabilité à long terme des indices standard du WISC-IV

By a Test–Retest procedure, this study explores the long-term stability of the French WISC-IV index scores. The average Test–Retest interval was 2.33 years. The sample consisted of 96 non-clinical children aged between 8 and 12 years. Mean difference between the two testings was not statistically significant for VCI, PRI, WMI, GAI and FSIQ. Test–Retest reliability correlations between the two assessments are high for VCI, GAI and FSIQ (ranging from .81 to .82). An analysis of the performance differences between two assessments indicates intra-individual stability for WMI and GAI. In sum, only GAI demonstrates reliable long-term stability at an inter-and intra-individual level.     

Use of the Peabody Picture Vocabulary Test with the educationally handicapped

Despite widespread use of the Peabody Picture Vocabulary Test (PPVT) as a measure of intelligence for educationally handicapped students, few studies have related PPVT scores of such students to their scores on the Wechsler Intelligence Scale for Children (WISC). Using 100 public school students consecutively referred for learning difficulties, their mean PPVT IQ (97.75) was found to be consistently and significantly higher than WISC Full Scale IQ (89.65), Verbal IQ (88.68), and Performance IQ (92.73). Correlations between the PPVT IQ and the WISC Full Scale, Verbal, and Performance IQs were .70, .69, and .54, respectively. A tabular summary of previous studies comparing PPVT and WISC IQs is included.     

Factor structure of the Norwegian version of the WAIS-III in a clinical sample: the arithmetic problem

Confirmatory Factor Analyses (CFA) of the Wechsler Adult Intelligence Scale-III (WAIS-III) lend partial support to the four-factor model proposed in the test manual. However, the Arithmetic subtest has been especially difficult to allocate to one factor. Using the new Norwegian WAIS-III version, we tested factor models differing in the number of factors and in the placement of the Arithmetic subtest in a mixed clinical sample (n = 272). Only the four-factor solutions had adequate goodness-of-fit values. Allowing Arithmetic to load on both the Verbal Comprehension and Working Memory factors provided a more parsimonious solution compared to considering the subtest only as a measure of Working Memory. Effects of education were particularly high for both the Verbal Comprehension tests and Arithmetic.     

Scores composites CHC pour le WISC-IV : normes francophones

Although the WISC-IV references the Cattell–Horn–Carroll (CHC) theory in the manual, the composite scores of this battery (VCI, PRI, WMI, and PSI) were not defined according to this model. Nevertheless, we recommend examining the subtests scores of the WISC-IV in reference to the nomenclature of the cognitive abilities proposed in the CHC theory, so as to bring additional insight on the observed performance. The objective of the first part of this paper is to provide normative tables for five CHC cognitive abilities of the French WISC-IV: fluid reasoning (Gf), comprehension–knowledge (Gc), visual processing (Gv), short-term-memory (Gsm), and processing speed (Gs); these tables were created using a statistical approximation procedure. The objective of the second part is to test the validity of these tables with data obtained from 250 children. Correlation between the standard indices of the WISC-IV (VCI, PRI, WMI, and PSI) and the CHC composite scores were high, demonstrating the validity of these CHC scores. These tables, for the French version of the WISC-IV, allow using the CHC composite scores as complementary measures, in order to conduct normative and ipsative analyses.     

Comparaison de quatre formes abrégées de l’échelle d’intelligence de Wechsler pour adultes – troisième édition (WAIS-III)

The French-speaking researchers and clinicians who assess intelligence with the WAIS-III, but have few time or evaluate individuals unable to cope with long standardized tasks, have often to construct their own short scale, arbitrarily selecting some subtests or shortening these subtests without respect of their psychometrical properties. In this study, our goal was to fill in this lack of a French short form of the WAIS-III. We compared four short forms developed on the basis of the factorial structure of the scale and on the psychometrical properties of the French norms. Using comprehensive statistical analysis, we identified one among the four forms that provide the best estimate, with the smallest error of measurement, of the IQ measured with the WAIS-III full scale.     

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 .     

Psychometric adequacy and comparability of the short and full forms of the Personality Assessment Inventory

The 160-item short form of the Personality Assessment Inventory (PAI) was developed for situations in which respondents complete only the 1st half of the test. The present study evaluates the adequacy and comparability of the full and short forms of the PAI in terms of a wide range of psychometric characteristics. In all, 421 participants completed the full form as part of a neuropsychological evaluation. Results indicated slightly lower internal consistency reliability of the short compared with the full form. Group-level agreement of short and full form scales ranged from adequate to excellent. However, within-subject agreement was somewhat more variable. Low levels of within-subject agreement were strongly associated with elevated validity scale scores. The factor structures of the full and short forms showed high congruence for a 3-factor solution. These findings suggest that many scales of the short form have adequate comparability with their respective full form scales. However, low levels of reliability across less impaired ranges of the latent trait, diminished content coverage, and altered validity detection may limit the utility of some of the short form scales.     

Short form and factor-analytic studies of the WISC-R with behavior problem children

Two analyses of the WISC-R protocols of 100 children referred for behavioral problems in school were conducted to study (a) the utility of a variety of WISC short forms and (b) the factor structure of the WISC-R. Although the correlations between short form and WISC-R IQs were highly significant, mean differences and a high percentage of IQ classification changes indicated that the short forms were not acceptable WISC-R substitutes. Different factor analyses consistently evidenced two factors, Verbal Comprehension and Perceptual Organization, which corresponded perfectly to the Verbal and Performance.     

II. The comparability of the WISC-R and WAIS among 16-year-old EMR children

Thirty 16-year-old EMR children were administered the WAIS and WISC-R in counterbalance order to determine the comparability of the two assessment instruments. The WAIS was found to yield significantly higher Verbal, Performance, and Full Scale IQ scores. The comparisons of corresponding subtests indicate that all WAIS subtests were significantly higher than the WISC-R except Picture Completion. Correlations between corresponding WAIS and WISC-R IQ scales and subtests, however, were significant. The results suggest differences between the two instruments among children of subnormal intelligence, thus presenting the possibility that a child may be differentially classified based on the selection of the intelligence test.     

Relationship between intelligence and vocabulary

This study explored the correlations of scores on the Wechsler Intelligence Scale for Children-III in screening language problems and scores on the three Comprehensive Receptive and Expressive Vocabulary Test subscales. Participants were 243 students ages 6 to 17 years in Grades K-11 who were identified as learning disabled, learning disabled with speech impairment, mentally retarded, and speech impaired. Analysis indicated strong correlations between the two measures, particularly between the CREVT General Vocabulary and WISC-III Verbal IQ (r = .80), WISC-III Verbal Comprehension Index (r =.83), and the Vocabulary subtest (r =.76). These results held across the grades. Supporting earlier studies of relationships of Verbal IQ and Receptive Vocabulary, correlations were lower between participants in Grades K through 2 than those in higher grades on the WISC-III Verbal IQ and the Receptive Vocabulary subtest. An analysis of the accuracy of the WISC-III for classifying students with language problems indicated improvement in classification over chance. These findings suggest that the WISC-III may be an effective screen for language problems.