Confirmatory factor analyses of the WAIS-III standardization data

Confirmatory factor analyses with the standardization data of the Wechsler Adult Intelligence Scale-Third Edition(Wechsler, 1997a) compared 6 models w ith 1 to 4 factors for 11- and 13-subtest versions of the test. Three facto rs usually fit the data better than 2 factors, but 2-factor models were mor e parsimonious. A 2-factor model with a Verbal Comprehension factor (Vocabu lary, Similarities, Information, and Comprehension) was as good as and some times better than the 2-factor model defined by the traditional separation of Verbal and Performance subtests. For 3-factor models, alternative specif ications of processing speed subtests on either the Perceptual Organization or Freedom From Distractibility factor were comparable, and specifying a 4 th factor for Digit Symbol and Symbol Search bad little advantage in compar ison with 3-factor models with correlated errors for the 2 subtests.