What Does the Cognitive Assessment System (CAS) Measure? Joint Confirmatory Factor Analysis of the CAS and the Woodcock-Johnson Tests of Cognitive Ability (3rd Edition)

Abstract

Results of recent research by Kranzler and Keith (1999) raised important questions concerning the construct validity of the Cognitive Assessment System (CAS; Naglieri & Das, 1997), a new test of intelligence based on the planning, attention, simultaneous, and sequential (PASS) processes theory of human cognition. Their results indicated that the CAS lacks structural fidelity, leading them to hypothesize that the CAS Scales are better understood from the perspective of Cattell-Horn-Carroll (CHC) theory as measures of psychometric g, processing speed, short-term memory span, and fluid intelligence/broad visualization. To further examine the constructs measured by the CAS, this study reports the results of the first joint confirmatory factor analysis (CFA) of the CAS and a test of intelligence designed to measure the broad cognitive abilities of CHC theory—the Woodcock-Johnson Tests of Cognitive Abilities-3rd Edition (WJ III; Woodcock, McGrew, & Mather, 2001). In this study, 155 general education students between 8 and 11 years of age (M = 9.81) were administered the CAS and the WJ III. A series of joint CFA models was examined from both the PASS and the CHC theoretical perspectives to determine the nature of the constructs measured by the CAS. Results of these analyses do not support the construct validity of the CAS as a measure of the PASS processes. These results, therefore, question the utility of the CAS in practical settings for differential diagnosis and intervention planning. Moreover, results of this study and other independent investigations of the factor structure of preliminary batteries of PASS tasks and the CAS challenge the viability of the PASS model as a theory of individual differences in intelligence.