A Confirmatory Analysis of the Factor Structure and Cross-Age Invariance of the Wechsler Adult Intelligence Scale-Third Edition.

In the Wechsler Adult Intelligence Scale-Third Edition (WAIS-III; D. Wechsler, 1997), the manual reports several confirmatory factor analyses in support of the instrument's latent factor structure. In practice, examiners frequently compare an examinee's score from a current administration of the WAIS-III with the results from a previous test administration. Implicit in test-retest score comparisons is evidence that scores retain similar interpretive meaning across time. Establishing an instrument's factorial invariance provides the foundation for this practice. This study investigated the factorial invariance of the WAIS-III across the instrument's 13 age groups. The overall results from this study generally support both configural and factorial invariance of the WAIS-III when the 11 primary tests are administered. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Standardization of the Wechsler Adult Intelligence Scale for older persons.

The primary purpose of this project is the standardization of the WAIS for older groups. A probability sample of the population of Kansas City was drawn and 475 persons, aged 60 and over, were given all the Verbal tests. For approximately 25% of these cases, one or more of the performance tests could not be used for various reasons. In addition to the standardization data, it was found that a) additional time makes very little difference in the scores; and b) the differences between the sexes on the WAIS were quite small. In general, the decline of verbal abilities with age is relatively small until about age 70. The decline in Performance measures is somewhat greater. There appears to be a similar factorial composition of the WAIS at all age levels. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Values for Comparison of WAIS-III Index Scores With Overall Means.

The Wechsler Adult Intelligence Scale-Third Edition (WAIS-III; Wechsler, 1997b) provides factor-based index scores but allows only for pairwise comparison of these scores, producing inflated Type I error rates and reducing profile interpretability. This article provides tables for simultaneous comparison to the overall mean index score, thus reducing error rates and aiding interpretation. The Working Memory Index or Processing Speed Index can also be specifically compared when an individual is believed to have a condition, such as a learning disability or traumatic brain injury, associated with the selective depression of these indexes. Tables for the infrequency of specific differences are also provided, allowing the practitioner to note how unusual an obtained difference is in the general population. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Age-related invariance of abilities measured with the Wechsler Adult Intelligence Scale-III.

Examination of measurement invariance tests the assumption that the model underlying a set of test scores is directly comparable across groups. The observation of measurement invariance provides fundamental evidence for the inference that scores on a test afford equivalent measurement of the same psychological traits among diverse groups. Groups may be derived from different psychosocial backgrounds or different clinical presentations. In the Wechsler Adult Intelligence Scale-III (WAIS-III)/Wechsler Memory Scale-III (WMS-III) Technical Manual (Psychological Corporation, 2002), there appears to be a breakdown in factor structure among the standardization cases in older adults. In this study, the authors evaluated the invariance of the measurement model of the WAIS-III across 5 age bands. All components of the measurement model were examined. Overall, the evidence pointed to invariance across age of a modified 4-factor model that included cross-loadings for the Similarities and Arithmetic subtests. These results support the utility of the WAIS-III as a measure of stable intelligence traits across a wide age range. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Confirmatory factor analysis of the Wechsler Intelligence Scale for Children-Third Edition in an Australian clinical sample.

A confirmatory factor analysis was conducted on the Wechsler Intelligence Scale for Children-Third Edition (WISC-III; D. Wechsler, 1991) with a sample of 579 Australian children referred for assessment because of academic difficulties in the classroom. The children were administered the WISC-III as part of the initial eligibility determination process for funding of special education services. The children were aged between 6 years and 16 years 7 months. One-, two-, three-, and four-factor models were tested. The four-factor model proposed in the WISC-III manual fit the data significantly better than all other models tested. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Two abbreviated versions of the Wechsler Adult Intelligence Scale-III: Validation among persons with traumatic brain injury.

Objective: To examine the clinical value of two 7-subtest versions of the Wechsler Adult Intelligence Scale-III (WAIS-111): one using Block Design (WAIS-III/BD7) and another using Matrix Reasoning (WAIS-III/MR7) among persons with traumatic brain injury (TBI). Study Design: Actual obtained scores from the full WAIS-111 were compared with scores that would have been obtained using each of the two abbreviated versions. Participants: One hundred eighteen persons with TBI tested consecutively in an academic medical center outpatient neuropsychology laboratory. Results: For the WAIS-IIVBD7, corrected validity coefficients were .97 (Verbal IQ [VIQI), .94 (Performance IQ [PIQ]), and .97 (Full Scale IQ [FSIQJ); 92%, 70%, and 92% of scores fell within 5 points of full version scores for VIQ, PIQ, and FSIQ, respectively. WAIS-III/MR7 corrected validity coefficients were .97 (VIQ), .95 (PIQ), and .97 (FSIQ); 92%, 76%, and 92% of short-form scores were within 5 points of actual scores for VIQ, PIQ, and FSIQ, respectively. Conclusions: Both abbreviated versions demonstrated acceptable psychometric characteristics, but the matrix reasoning version may be more advantageous in assessing persons with TBI because it can be used with persons who have TBI-related motor skills impairment. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Adult Age and Digit Symbol Substitution Performance: A Meta-Analysis.

This article reports the results of a meta-analysis of the effects of age, education, and estimated year of measurement on scores from the Wechsler Adult Intelligence Scale and the Wechsler Adult Intelligence Scale-Revised Digit Symbol Substitution Test. Analysis of effect sizes for age reported in 141 studies published between 1986 and 2002 indicated a mean standardized difference of -2.07. Age accounted for 86% of the variance in a regression model using age, education, and year submitted as predictors of Digit Symbol scores. There was no association between years of education or year submitted and Digit Symbol scores for younger adults or older adults. (PsycINFO Database Record (c) 2010 APA, all rights reserved)