One of the primary reasons may be the use of different IQ tests (by different psychologists) that vary in their breadth of measurement of the major domains of human intelligence. In particular, I will focus on the contemporary consensus psychometric theory known as CHC theory to explain score differences. What is CHC theory?
The Cattell-Horn-Carroll Theory of Cognitive Abilities (aka., CHC theory) is now serving as the blueprint for the development and/or revision of most major intelligence tests. It is only a matter of time before the courts begin receiving expert testimony (and or reports) based on CHC-designed IQ batteries or non-CHC IQ batteries interpreted via the CHC lens.
This current post is intended to make readers aware of the prominence of CHC theory in intelligence testing circles. Its application to IQ test results in Atkin's cases will be discussed in future posts. For now, readers should check out the two best overview articles the describe CHC theory. Yes...they are written by the blogmaster. This is not boasting...this is just a factual statement. The two references are listed below. One was an invited editorial in the journal Intelligence and the other a recent book chapter. Links to the sources are provided below (note - the link for the book chapter is to a 2004 pre-publication web-based version of the eventual 2005 book chapter).
- McGrew, K. (2009). Editorial: CHC theory and the human cognitive abilities project: Standing on the shoulders of the giants of psychometric intelligence research, Intelligence, 37, 1-10. (click here to view or download pdf)
- McGrew, K. S. (2005). The Cattell-Horn-Carroll (CHC) theory of cognitive abilities: Past, present and future. In D. Flanagan, & Harrison (Eds.), Contemporary intellectual assessment: Theories, tests, and issues (p.136-202). New York: Guilford Press. (click here to view web-based version of chapter)
Stay tuned. Much more on this topic in the future. If readers want to stay abreast re: the most recent CHC theory and assessment research, I post this information at a sister blog (Intelligent Insights on Intelligence Theories and Tests; aka., IQs Corner)
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