IAP AP101 # 4 report is now available (click here for all AP101 reports and briefs). "IAP AP101 Report #4: Cluster analysis of the WJ III Battery: Implications for CHC test interpretation and possible CHC model extensions" can be downloaded or viewed by clicking here.
PPT files are also viewable and downloadable via SlideShare.
The WJ III Battery is comprised of both cognitive (intelligence) and achievement components. As reported in the technical manual, the Cattell-Horn-Carroll (CHC) theory of cognitive abilities organizational structure of the WJ III has been validated. The current investigation analyzed the cognitive and achievement tests for all WJ III norm subjects from ages 6-18 years of age. Cluster analysis of the 50 WJ III tests provides additional validity for the CHC structure of the WJ III. More importantly, the analyses provide support for a significant number of narrow ability classifications for many WJ III tests, classifications that (to date) have largely been based on expert consensus task analysis. The results also suggest possible new interpretative clusters and intermediate CHC dimensions warranting future research regarding the CHC taxonomy of human cognitive abilities.