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Confirmatory Factor Analysis of the WPPSI-R at the Extreme End of the Age Range

This study investigated the adequacy of a two-factor interpretation of the WPPSI-R for the upper- and lower-most age groupings of the standardization sample. Previous research has shown that a two-factor model best represents the underlying structure of the WPPSI-R for the standardization sample taken as a whole. However, the two extreme age bands that are most likely to stray from this interpretation have not been investigated. Past confirmatory factor-analytic research on tests of cognitive abilities generally has shown that fewer factors are supported for very young age groups, while additional factors may be supported for older age groups. Therefore, maximum likelihood confirmatory factor analyses were conducted separately on the WPPSI-R standardization sample for the two extreme age groupings (ages 3 and 7). A one-, two-, and three-factor solution was imposed on the data. A comparison of underlying theory and goodness-of-fit statistics revealed that the two-factor solution provided the best fit to the data for both samples. In addition, the fit improved when Picture Completion was allowed to load on both the Verbal and Performance factors. The results support the interpretation of two consistent factors across the entire age range of the WPPSI-R.