Saturday, July 02, 2005

Differentail Ability Scales (DAS) and CHC theory - a research study

AN Dissertation Abstract: 2004-99024-119. AU Sanders, Sarah J.

TI A joint confirmatory factor analysis of the differential ability scales and the Woodcock-Johnson tests of cognitive abilities - third edition.

SO Dissertation Abstracts International: Section B: The Sciences & Engineering. Vol 65(6-B), 2004, 3218. US: Univ Microfilms International.


  • Human cognitive ability has been a popular area of research that has developed over the past century. Theories and measures of ability have ranged from very simplistic definitions and tests, such as a global intelligence construct (IQ) and single sensory/motor tests to highly complex multiple ability theoretical conceptualizations with corresponding batteries of tests. Additionally, the mandated use of intellectual measures for guiding educational and diagnostic decisions has led to a steady increase in the development of cognitive batteries and the need for a clearer understanding of what constructs these tests measure. The purpose of this study was to investigate the Differential Ability Scales (DAS; Elliott, 1990a), a standardized measure of cognitive ability, in relation to the Cattell-Horn-Carroll (CHC) theory of cognitive abilities. The CHC theory is a hierarchical three-tiered taxonomy consisting of has an overall general ability (Stratum III), with several broad abilities (Stratum II) that consist of numerous narrow abilities (Stratum I). This was accomplished by analyzing the DAS in conjunction with the Woodcock-Johnson Tests of Cognitive Abilities-Third Edition (WJ-III COG; Woodcock, McGrew, & Mather, 2001b), a contemporary cognitive ability measure developed based on the CHC theory. A group of 133 school-aged children were administered the DAS and WJ-III COG. Several variations of the CHC model were examined to determine which provided the best representation of the underlying CHC constructs measured by the DAS. Results of these confirmatory factor analyses supported the interpretation of the DAS from a CHC theoretical perspective. Moreover, this study confirmed that the DAS contains relatively strong measures of six of the CHC second-stratum abilities. Although a two-stratum CHC model provided the best statistical representation, results suggested that the complete, hierarchical three-stratum CHC model also should be considered a tenable solution. Specifically, these results confirmed that most of the CHC abilities (Gc, Gv, Glr, Gs, Gf, and Gsm) are measured on the DAS cognitive battery, with each of the DAS subtests representing primary indicators (Strata I narrow abilities) of these broad ability domains.

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