WAIS-R performance following closed-head injury: A comparison of the clinical utility of summary IQs, factor scores, and subtest scatter indices

WAIS-R performance can be analyzed at the level of the IQs. factor scores, or subtests. This study examined the relative utility of such analyses in a closed-head-injured (CHI) sample (n = 233). Comparison of the sample with matched controls (n = 117) indicated that factor scores may be the most appropriate level of analysis in clinical practice. This conclusion was supported by a series of discriminant function analyses performed on the WAIS-R scores of the CHI sample and 356 healthy controls drawn from the general population. Factor scores achieved a significantly higher classification accuracy than IQs or indices of subtest scatter (all ps < .001). Combining the scatter indices with the composite measures (i.e.. IQs or factor scores) did not produce a significant improvement in discrimination over that achieved by the composites alone. Counter to the assumptions underlying the clinical analysis of subtest profiles, CHI participants failed to exhibit significantly greater intraindividual subtest variability in their subtest profiles than the matched control sample.