Factor Structure of the Differential Ability Scales–Second Edition Core Subtests: Standardization Sample Confirmatory Factor Analyses

The present study examined the factor structure of the Differential Ability Scales–Second Edition (DAS-II) core subtests from the standardization sample via confirmatory factor analysis (CFA) using methods (bifactor modeling and variance partitioning) and procedures (robust model estimation due to nonnormal subtest score distributions) recommended but not included in the DAS-II Introductory and Technical Handbook. CFAs were conducted with the three DAS-II standardization sample age groups (lower early years [age = 2:6–3:5 years], upper early years [age = 3:6–6:11 years], school age [7:0–17:11 years]) using standardization sample raw data provided by NCS Pearson, Inc. Although most DAS-II core subtests were properly associated with the theoretically proposed group factors, both the higher order and bifactor models indicated that the g factor accounted for large portions of total and common variance, whereas the group factors (Verbal, Nonverbal, Spatial) accounted for small portions of total and common variance. The DAS-II core battery provides strong measurement of general intelligence, and clinical interpretation should be primarily, if not exclusively, at that level.