The promise of CHC theory of intelligence

Combine the past 20 years of CHC-driven intelligence test development and research activities (click here and here) with the ongoing refinement and extension of CHC theory (McGrew, 2005; 2009) and one concludes that these are exciting times in the field of intelligence testing. But is this excitement warranted in school psychology? Has the drawing of a reasonably circumscribed “holy grail” taxonomy of cognitive abilities led us to the promised land of intelligence testing in the schools—using the results of cognitive assessments to better the education of children with special needs? Or, have we simply become more sophisticated in the range of measures and tools used to “sink shafts at more critical points” in the mind (see Lubinksi, 2000) which, although important for understanding and studying human individual differences, fails to improve diagnosis, classification, and instruction in education?

It is an interesting coincidence that McDermott, Fantuzzo, and Glutting’s (1990) now infamous and catchy admonition to psychologists who administer intelligence tests to “just say no to subtest analysis” occurred almost 20 years ago—the time when contemporary CHC intelligence theory and assessment was emerging. By 1990, McDermott and colleagues had convincingly demonstrated, largely via core profile analysis of the then current Wechsler trilogy of batteries (WPPSI, WISC-R, WAIS-R) that ipsative strength and weakness interpretation of subtest profiles was not psychometrically sound. In essence, “beyond g (full scale IQ)—don’t bother.”

I believe that optimism is appropriate regarding the educational relevance of CHC- driven test development and research. Surprisingly, cautious optimism has been voiced by prominent school psychology critics of intelligence testing. In a review of the WJ-R, Ysseldyke (1990) described the WJ-R as representing “a significant milestone in the applied measurement of intellectual abilities” (p. 274). More importantly, Ysseldyke indicated he was “excited about a number of possibilities for use of the WJ-R in empirical investigations of important issues in psychology, education, and, specifically, in special education…we may now be able to investigate the extent to which knowledge of pupil performance on the various factors is prescriptively predictive of relative success in school. That is, we may now begin to address treatment relevance.” (p. 273). Reschly (1997), in response to the first CHC-based cognitive-achievement causal modeling research report (McGrew, Flanagan, Keith & Vanderwood, 1997) which demonstrated that some specific CHC abilities are important in understanding reading and math achievement above and beyond the effect of general intelligence (g), concluded that “the arguments were fairly convincing regarding the need to reconsider the specific versus general abilities conclusions. Clearly, some specific abilities appear to have potential for improving individual diagnoses. Note, however, that it is potential that has been demonstrated” (Reschly, 1997, p. 238).

Clearly the potential and promise of improved intelligence testing, vis-à-vis CHC organized test batteries, has been recognized since 1989. But has this promise been realized during the past 20 years? Has our measurement of CHC abilities improved? Has CHC-based cognitive assessment provided a better understanding of the relations between specific cognitive abilities and school achievement? Has it improved identification and classification? More importantly, in the current educational climate, where does CHC- grounded intelligence testing fit within the context of the emerging Response-to-Intervention (RTI) paradigm?

An attempt to answer these questions will be forthcoming in a manuscript submitted for publication (McGrew & Wendling, 2009) as well as a revision of the CHC COG-ACH Relations Research Synthesis Project available at IQs Corner (warning - current posted material is now outdated and does not reflect the final conclusions of the McGrew & Wendling (2009) review. This material is in the process of being revised and will be posted soon. Stay tuned to IQs Corner Blog or announcements via the NASP and CHC listservs.

Click here for other posts in this series.