Differential Ability Scales
as Measure of g
Examination of the loadings on the first unrotated factor—in either a
principal components analysis or a factor analysis—allows one to determine the
extent to which the DAS subtests measure general intelligence, or g.
The seventeen DAS subtests had g loadings ranging from a low of .27 (Recall
of Objects) to a high of .80 (Verbal Comprehension). Across all ages, the
subtests form two clusters with respect to the measurement of g: (a) Core
subtests at each level are good or fair measures of g, averaging .68 (range .53
to .82), and (b) Diagnostic subtests are poor measures of g, averaging .40
across the three levels (range .28 to .55). Only Matching Letter-Like Forms
differed from this pattern, being a diagnostic subtest with fair g loadings
across the ages. Overall, the g loading pattern is a reflection of the decisions
made during test development to allow only those subtests that yielded high g
loading to contribute to the core while allowing those subtests with lower g
loading to be considered diagnostic.