Factor Analysis of the WAIS-R Using the Factor Replication Procedure, FACTOREP

Abstract

The factor structure of the WAIS-R has been the subject of much debate and recently researchers have examined multiple independent samples and compared the resulting factor structures using the coefficient of congruence. On the basis of this, one recent study concluded that the WAIS-R had three clear factors. In the present study this conclusion was questioned and it was claimed that the previous result was an artifact caused by the large general factor found in the WAIS-R. The present study aimed to clarify the situation by using identical data but the alternative factor comparison technique, FACTOREP, which was able to reduce the influence of both error variance and the general factor. On the basis of this comparison it was demonstrated that the WAIS-R has two strong factors but that there is little evidence for the existence of a third factor.

Structure of the Wechsler Adult Intelligence Scale – Revised in the Italian Normal Standardisation Sample

“…Therefore, some investigations have supported the extraction and the predictability of one-factor model defined as Spearman's g (Blaha & Walbrown, 1982;O'Grady, 1983;Ryan, Paolo, & Brungardt, 1990;Silverstein, 1982). Others (Athanasou, 1993;Gutking, Reynolds, & Galvin, 1984;Plake, Gutkin, Wise, & Kroeten, 1987;Ryan, Paolo, & Smith, 1992;Ryan, Rosenberg, & DeWolfe, 1984;Siegert, Patten, Taylor, & McCormick, 1988;Sturmey, Gatherer, Ghadiali, Hallett, and Searle, 1993) have supported only two-factor models defined as Verbal IQ and Perfomance IQ, such a distinction was already preferred by Wechsler (1981). In the twofactors model, Information, Vocabulary, Comprehension, Similarities, Arithmetic, and Digit Span load on a verbal factor, whereas Picture Completion, Picture Arrangement, Block Design, Object Assembly, and Digit Symbol load on a nonverbal factor.…”

A reexamination of the WAIS—R factor structure.

“…On the basis of the results of these analyses, and relying heavily on the likelihood ratio chi-square statistic and the Bentler and Bennett (1980) normed fit index (NFI), O'Grady concluded that the simplest solution, a single general factor, was sufficient to account for the WAIS-R subtest intercorrelations and was therefore preferable. Siegert et al (1988) also compared alternative factor models for the WAIS-R, using the WAIS-R standardization sample. In contrast to O'Grady (1983), however, these authors relied on factor-matching procedures to determine the factor structure that is most genemiizable over different data sets.…”

Factor analysis of the Wechsler Adult Intelligence Scale—Revised for persons 75 years and older.

“…It has been argued that a single-factor solution represents underfactoring of the scale (Siegert, Patten, Taylor, & McCormick, 1988) and that the number of factors to be interpreted should ultimately depend on careful inspection of each client's profile (Naglieri & Kaufman, 1983). Thus the two-factor interpretation is appropriate when the Arithmetic subtest scaled score does not deviate significantly from the Verbal Scale mean and when the Picture Completion and Picture Arrangement scaled scores do not differ significantly from the Performance Scale mean.…”