Factor Analysis reported in the DAS Introductory and Technical Handbook
reports a series of both confirmatory and exploratory factor analyses of the
standardization sample. The results indicated that, for the most part, the
structure of abilities assessed by the DAS becomes more distinct as the child’s
age increases. One factor provided the best fit for the core subtests for the
youngest children, two factors emerges as the child’s cognitive abilities
increase, and a final, three-factor model is the best fit for the abilities of
the school-age child. In addition to the factors created from the robust
g-saturated subtests, the lower g-loaded diagnostic subtests provide additional
information about a child’s ability, independent of the core subtests.
Further support for the factors of the DAS was provided by both independent
analysis of the DAS standardization sample (Keith 1990; Stone, 1992) and
analysis of a separate, smaller sample of children (Byrd & Buckhalt, 1991).
Keith (1990) found that there was strong support for concluding that the
constructs measured by the DAS are "remarkably consistent across the
overlapping age levels of the test" (p. 403). Although he chose to label
the DAS Spatial factor "Nonverbal Reasoning" and the Nonverbal
Reasoning factor "Gf," Keith accepts that the DAS Verbal, Nonverbal
Reasoning, and Spatial factors are good measures of Gc, Gf, and Gv respectively.
Stone (1992) found support for the three-factor structure of the core subtests
for school-age children: Verbal, Nonverbal Reasoning, and Spatial Abilities.
Using a multitrait-multimethod analysis of construct validity, Byrd and
Buckhalt found support for the overall general conceptual ability (GCA) and the
specificity of selected subtests for profile analysis. Although several
researchers have questioned how well the names of the DAS clusters describe the
constructs they measure, it is generally assumed that the DAS Nonverbal
Reasoning may be considered a strong measure of Fluid intelligence (Gf) (Keith,
1990, Elliott, 1990). This assumption has both empirical (Keith 1990, 1997;
McGhee, 1993) and theoretical (McGrew, 1997; McGrew & Flanagan, 1998)
support. Using the The McGrew, Flanagan, and Ortiz Integrated Carroll/Cattell-Horn
model of abilities, the DAS Verbal cluster most likely represents Crystallized
Intelligence (Gc) while the Spatial Cluster reflects primarily Visual Processing
(Gv) (McGrew & Flanagan, 1998, ch. 4, Appendix A).