Sunday, October 4, 2009

Atkins MR death penalty IQ test-theory gap: Is this a problem?

[Double cllck on image to enlarge: Click here for a more comprehensive figure that includes IQ tests without adult norms]

Contemporary Cattell-Horn-Carroll (CHC) theory has emerged as the psychometric cognitive/intelligence theory with the largest body of supporting evidence (Kaufman, 2009).  Evidence for the emergence of CHC theory can be seen in a recently invited editorial on CHC theory in the prestigious journal Intelligence (McGrew, 2009).  More importantly, CHC theory “has formed the foundation for most contemporary IQ tests” (Kaufman, 2009, p. 91).

If CHC theory is now the consensus model of psychometric intelligence, and if the intellectual component of most Atkins cases hinges on one of the latest versions of the WAIS (WAIS-III, WAIS-IV), which is often described as the "IQ test standard" in Atkins related decisions, isn't this a serious problem?

Shouldn't life-or-death decisions hinging (to a major degree) on a person's tested level of intelligence be based on the assessment of intelligence as per the most validated model of intelligence?

Would the Vidal (2007) CA decision, which hinged largely on expert debates surrounding existing (prior) Wechsler Verbal, Performance and Full Scale IQ scores, benefited from less debate regarding the meaning of a consistently documented Verbal vs Performance IQ difference and more time spent asking for more comprehensive assessments of Vidal's complete CHC cognitive abilities, many that are either not measured, or are poorly represented, by the Wechsler batteries?

Should the Wechslers continue to be considered "the IQ standard" in these cases?  Shouldn't a standard be consistent with the consensus model of contemporary of intelligence?

It appears that many Atkins IQ MR-determination cases are decided in the presence of an IQ test-contemporary intelligence theory gap.  How long will this continue?   What are the implications?

Many questions to ponder.

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