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)

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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 GAS, 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 stud ents 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.

Naglieri and Das (1997) developed the Cognitive Assessment System (CAS) to assess the planning, attention, and simultaneous-successive (PASS) cognitive processes of children and adolescents from 5 through 17 years of age. According to the PASS theory of intelligence, information processing is related to three functional units of the brain: (a) planning entails the formulation, selection, and regulation of plans of action; (b) attention involves the distribution of cognitive resources and effort; and (c) simultaneous and successive processing comprise the cognitive processes used in the acquisition, storage, and retrieval of information (for a summary, see Das, Naglieri, & Kirby, 1994). Naglieri (1997) stated that "the PASS processes are dynamic in nature, respond to the cultural experiences of the individual, are subject to developmental changes, and form an interrelated (correlated) interdependent system" (p. 250). Although the PASS processes are seen to be related, they are nonetheless conceptualized as "ph ysiologically and functionally distinct" (Naglieri, Das, & Jarman, 1990, p. 429).

At the current time, the CAS is one of the few tests of intelligence derived from a theory of information processing and the only test based entirely on the PASS theory (for reviews, see Flanagan, Genshaft, & Harrison, 1997). "The purpose of the CAS is to measure specific abilities defined as PASS cognitive processes. These processes are considered the basic dimensions of ability" (Naglieri, 1999a, p. 10). Naglieri and Das claim that the CAS has substantiated validity for the following uses: "diagnosis of learning strengths and weaknesses; classification (learning disabilities, attention deficit, mental retardation, giftedness); eligibility decisions (meeting state or federal criteria); and consideration of the appropriateness of particular treatment, instructional, or remedial programs" (p. 9; cf. Naglieri, 1999a).

Results of recent research, however, raised serious questions about the construct validity of the CAS (Keith & Kranzler, 1999; Kranzler & Keith, 1999; Kranzler, Keith, & Flanagan, 2000). Kranzler and Keith (1999) analyzed the standardization data of the CAS with confirmatory factor analysis (CFA) techniques to address several important and unresolved issues suggested by research on preliminary batteries of PASS tasks (Carroll, 1995; Kranzler & Weng, 1995a, 1995b; Naglieri, Das, Stevens, & Ledbetter, 1991). …