The Cattell-Horn-Carroll (CHC) theory of abilities is a comprehensive model of human cognitive abilities denoted by the G-code. Developed by three prominent psychologists - Raymond Cattell, John Horn, and John Carroll - the CHC theory suggests that there are three strata of cognitive abilities. In this paper, the authors argued that the CHC model faces seven challenges: First, it is a complex model with numerous factors and subtests, posing difficulties in administration and interpretation. Second, the theory itself has limited coverage and may not address all cognitive abilities. Third, critics have been arguing that the CHC theory has failed to sufficiently address socio-cultural variations. Fourth, the CHC model of broad and narrow abilities lacks concrete operational definitions, relying on theoretical constructs. Fifth, it always fails to account for complex interactions between cognitive abilities. Sixth, the CHC model continually evolves, requiring frequent updates. Lastly, the CHC theory might not fully capture individual differences in cognitive abilities and potential, leaving room for improvement. There are alternative models (e.g., extended fluid-crystallized and verbal-perceptual-image rotation theories) to the CHC model. Despite these limitations, the CHC model remains a valuable tool for understanding cognitive abilities. In this paper, the authors have chosen to focus on the non-CHC categories of broad abilities with their respective narrow abilities. Termed as ancillary abilities denoted by the Q-code, this paper aims to provide another model of abilities (not necessarily cognitive), not to replace the current CHC model, but to complement or supplement it.


Ancillary Abilities, Broad Abilities, Cattell-Horn-Carroll (CHC) model, G-code, Narrow Abilities, Q-code,


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