This is an updated version of an OBG (oldie but goodie) post originally made in 2017.
The historical development of the CHC model of intelligence has been documented by McGrew (2005) and Schneider and McGrew (2012) and summarized by Kaufman and colleagues (Kaufman, 2009; Kaufman, Raiford & Coalson, 2016). Additional extensions and historical anecdotes were rececntly presented by McGrew (2023) in an article included in a special issue of the Journal of Intelligence focused on Jack Carroll’s tri-stratum theory @ 30 years. McGrew (2023) recommended that CHC theory should now be referred to as a group of CHC theories (i.e., a family of orthogonally correlated models) that recognizes the similarities and differences between the theoretical models of Cattell, Horn and Carroll.
An unexplained crucial, yet missing piece of the CHC story, is the origin of the original CHC broad and narrow ability definitions. The CHC ability definition birth certificate, until recently, had not been revealed. To fend off possible CHC “birther” controversies, I will now set the record straight again (as was first done in 2017) regarding the heritage of the past and current CHC definitions.
Given the involvement of both John Horn and Jack Carroll in revisions of the WJ-R and WJ III, which was the impetus for the combined CHC theory, it is not surprising that the relations between the “official” CHC ability definitions and the WJ tests were “reciprocal in nature, with changes in one driving changes in the other” (Kaufman et al., 2016, p. 253). Furthermore, “the WJ IV represented the first revision in which none of the original CHC theorists was alive at the time of publication, producing and imbalance in this reciprocal relationship—-“the WJ IV manuals now often served as the official source for the latest CHC theory and model of cognitive abilities (J. Schneider, personal communication, March 15, 2015)” (Kaufman et al., 2016; p. 253). Kaufman et al. noted that with the development of subsequent non-WJ CHC assessment and interpretation frameworks (e.g., Flanagan and colleagues CHC cross-battery assessment; Miller’s integrated school neuropsychology/CHC assessment model), some confusion has crept into what represents the authoritative “official” and “unofficial” definitions and sources.
In Schneider & McGrew (2012) and Schneider & McGrew (2018), the incestuous nature of the evolution of the CHC definitions continued by building primarily on the McGrew (2005) definitions, which in turn were reflected in the 2001 WJ III manuals, which in turn drew from McGrew (1997). In my original 2017 post regarding this topic, it was judged time to divorce the official CHC definitions from the WJ series and authors (particularly myself, Kevin McGrew).
However, the CHC birth certificate is still often questioned. Did the CHC definitions magically appear? Did they come down in tablet form from a mountain top? After the Cattell-Horn and Carroll models were first married by McGrew (1997), were the definitions the result of some form of immaculate conception? Did McGrew (1997) develop them unilaterally?
Here is….the “rest of the story.”
The original CHC definitions were first presented in McGrew’s (1997) chapter where the individual tests from all major intelligence batteries where classified as per the first integration of the Cattell-Horn and Carroll models of cognitive abilities (then called a “proposed synthesized Carroll and Horn-Cattell Gf-Gc framework”). In order to complete this analysis, I (Kevin McGrew) needed standard CHC broad and narrow definitions—but none existed. I consulted the Bible…Carroll’s Human Cognitive Abilities (1993).
I developed the original definitions (primarily the narrow ability definitions) by abstracting definitions from Carroll’s (1993) book. After completing the first draft of the definitions, I sent them to Carroll. He graciously took time to comment and edit the first draft. I subsequently revised the definitions and sent them back. Jack and I engaged in several iterations until he was comfortable with the working definitions. As a result, the original narrow ability definitions published in McGrew (1997) had the informal stamp of approval of Carroll, but not of Horn. The official CHC definition birth certificate should list Carroll and McGrew as the parents.
Since then the broad and narrow CHC ability definitions have been parented by McGrew (McGrew & Woodcock, 2001; McGrew, 2005; McGrew et al., 2014) and more recently, uncle Joel Schneider (Schneider & McGrew, 2012; Schneider & McGrew, 2018). The other WJ III and WJ IV authors (Mather, Schrank, and Woodcock) served as aunts and uncles at various points in the evolution of the definitions, resulting in the current “unofficial” definitions being in the WJ IV technical manual (McGrew et al., 2014) and the Schneider & McGew (2018) chapter.
With new data-based insights from the the validity analysis of the norm data from the forthcoming WJ V (LaForte, Dailey & McGrew, 2025, in preparation), the WJ V technical manual will provide, yet again, a slightly new and improved set of CHC definitions. Stay tunned.
No doubt the WJ V 2025 updated CHC definitions will still have a clear Carroll/McGrew, WJ III /WJ IV/WJ V and Joel Schneider genetic lineage (McGrew, 1997—>McGrew & Woodcock, 2001—>McGrew, 2005—>Schneider & McGrew, 2012—>McGrew et al., 2014—>Schneider & McGrew, 2012, 2018). We (Schneider and McGrew) are reasonably comfortable with this fact. However, we hope that the WJ—>WJ V set of CHC definitions will eventually move out of the influence of the WJ/CHC house and establish a separate residence, identity, and process for future growth. I am aware that Dr. Dawn Flanagan and colleagues are working on a new revision of their CHC cross-battery book and related software and will most likely include a new set of revised defintions. Perhaps a melding with the WJ V technical manual definition appendix with the work of Flanagan et al. would be a good starting point. Perhaps some group or consortium of interested professionals could be established to nurture, revise, and grow the CHC defintions.
