General Ability Index for the WAIS-III: Canadian Norms.

The Wechsler Adult Intelligence Scale-Third Edition (WAIS-III; Wechsler, 1997) permits the calculation of both traditional IQ and Index scores. The Verbal Comprehension and Perceptual Organization indexes are the most highly "g" loaded compared to the Working Memory and Processing Speed indexes that may be more sensitive to some neuro-cognitive disorders. In certain clinical situations, a general ability composite score based on the combination of only the verbal and performance indexes is desirable. Following the procedure for calculating a General Ability Index (GAI; Prifitera, Weiss, & Saklofske, 1998) for the Wechsler Intelligence Scale for Children-Third Edition (WISC-HI; Wechsler, 1991) and the WAIS-III (Tulsky, Saklofske, Wilkins, & Weiss, 2001), GAI normative tables for the WAIS-III Canadian standardization sample are reported here to complement earlier published GAI Canadian norms tables for the WISC-III. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Ipsative Comparisons of Index Scores for the Canadian WAIS-III.

The Canadian standardization of the Wechsler Adult Intelligence Scale--Third Edition (WAIS-III; Wechsler, 1997a, 2001) provides factor-based index scores, giving an intermediate level of analysis between IQ scores and individual subtests. This article provides tables for comparing all indices to the mean index score, and for identifying the statistical significance and relative frequency of obtained differences. This simultaneous or ipsative approach can avoid some of the statistical and logical pitfalls of multiple pairwise comparisons, such as decreased interpretability and inflated risk of Type I errors. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Sexual bias in the WAIS.

The WAIS protocols of 50 male and 50 female college students were analyzed for differential subtest performance. Although no significant differences were found for education, age, or Verbal, Performance, or Full Scale IQ, males were found to be highly superior on the Information, Arithmetic, Block Design, and Picture Arrangement subtests. Females were markedly superior on the Digit Symbol subtest. Wechsler's M-F score was calculated for each group and was found to differentiate the sexes better than any single subtest. The results suggest the presence of sexual bias in the WAIS even when age, education, IQ, and experience are held fairly constant. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The joint WAIS-III and WMS-III factor structure: Development and cross-validation of a six-factor model of cognitive functioning.

During the standardization of the Wechsler Adult Intelligence Scale (3rd ed.; WAIS-III) and the Wechsler Memory Scale (3rd ed.; WMS-III) the participants in the normative study completed both scales. This "co-norming" methodology set the stage for full integration of the 2 tests and the development of an expanded structure of cognitive functioning. Until now, however, the WAIS-III and WMS-III had not been examined together in a factor analytic study. This article presents a series of confirmatory factor analyses to determine the joint WAIS-III and WMS-III factor structure. Using a structural equation modeling approach, a 6-factor model that included verbal, perceptual, processing speed, working memory, auditory memory, and visual memory constructs provided the best model fit to the data. Allowing select subtests to load simultaneously on 2 factors improved model fit and indicated that some subtests are multifaceted. The results were then replicated in a large cross-validation sample (N=858). (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Comparison of the WISC and WAIS at chronological age sixteen.

A group of 30 Ss was tested with the WISC and 4 wk. later with the WAIS. During this interval they all passed their 16th birthdays. Since chronological age is constant, correlations were calculated for the various IQ scales of the 2 tests and indicated that IQs obtained at age 16 from the 2 scales are highly comparable. The mean IQs and standard deviations of the experimental groups were not significantly different from the mean IQs and standard deviations of the standardization groups. In the case of the Full Scale IQ, differences in individual Ss ranged from -11 to +13 points with a mean at +2.4 points (WAIS -WISC). In general, the results indicate that the transition from the WISC to the WAIS at age 16 introduces no significant errors in IQ determination. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Errors in intelligence estimation with short forms of the WAIS.

Because the full Wechsler Adult Intelligence Scale (WAIS) generally takes more than an hour of the clinician's time to administer, short forms based on a selection of subscales are often substituted. The present study shows that in many cases such short forms may give seriously inaccurate results. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Relationship between institutionalization, other demographic variables, and the structure of intelligence in chronic schizophrenics.

A factor analytic investigation was carried out studying the relationship between length of institutionalization and several other premorbid-demographic variables and the structure of the Wechsler Adult Intelligence Scale (WAIS) in a sample of chronic schizophrenics. Only 3 of these background variables were related to WAIS subtests. 2, education and aging, differentiated within this sample the same way as in the general population: i.e., education was associated with generally higher performance on all subtests while aging was selectively related to lowered psychomotor and memory/attentional functioning. The 3rd, length of institutionalization, showed negative relationship with Comprehension score, suggesting some impairment in social judgment. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Education-Stratified Base-Rate Information on Discrepancy Scores Within and Between the Wechsler Adult Intelligence Scale-Third Edition and the Wechsler Memory Scale-Third Edition.

The Wechsler Adult Intelligence Scale--Third Edition (WAIS-III; D. Wechsler, 1997a) and the Wechsler Memory Scale--Third Edition (WMS-III; D. Wechsler, 1997b) are 2 of the most frequently used measures in psychology and neuropsychology. To facilitate the diagnostic use of these measures in the clinical decision-making process, this article provides information on education-stratified, directional prevalence rates (i.e., base rates) of discrepancy scores between the major index scores for the WAIS-III, the WMS-III, and between the WAIS-III and WMS-III. To illustrate how such base-rate data can be clinically used, this article reviews the relative risk (i.e., odds ratio) of empirically defined "rare" cognitive deficits in 2 of the clinical samples presented in the WAIS-III--WMS-III Technical Manual (The Psychological Corporation, 1997). (PsycINFO Database Record (c) 2010 APA, all rights reserved)