1. Introduction 2. Evolution of CHC Theory A. Early psychometric heritage B. 1st Generation Gf-Gc Assessment Cattell-Horn Gf-Gc theory "discovered" Cattell-Horn Gf-Gc theory overview The Horn-Carroll-Woodcock "fortuitous" tripartite Publication of the Horn-Cattell Gf-Gc based WJ-R Battery Gf-Gc battery "free" assessment concept born Carroll's 1993 Principia Cognitive Abilities C. CHC (Gf-Gc) Investigations, Integrations, and Extensions The CIA book CHC: The rest of the story 3. Empirical Evaluations of the "complete" CHC Theory A. Large sample studies Studies with CHC designed batteries Studies with other batteries B. Small sample studies C. Summary and conclusions 4. CHC Theory Extensions A. Internal CHC structural extensions Gv Ga Gsm Should working memory be considered a CHC trait/factor? Gc/Gkn Speed abilities (Gs, Gt, Gps) Gs Gt B. External CHC structural extensions Tactile (Gh) and kinesthetic (Gk) abilities Olfactory abilities (Go) 5. Betwixt, behind and beyond g A. g: Betwixt Horn and Carroll Horn on g: Carroll on g: B. Behind g: Working Memory? WJ III CHC MW-to-g Studies Behind g: Summary C. Beyond g: CHC Lower-Stratum Abilities are Important CHC g+Specific-to- Achievement SEM Studies Beyond g: Summary 6. Summary & conclusions A. Conclusions and Caveats B. Implications and Future Directions C. References Related projects & key tables and figures used Carroll Human Cognitive Abilities Project (CA) Cattell-Horn (CHC) Definition Project Tables Table 1. Significant structural CHC theoretical, measurement and assessment developments: A continuum of progress Table 2: Comparison of Cattell-Horn and Carroll Theories of Human Cognitive Abilities Table 3. Broad (stratum II) and Narrow (stratum I) Cattell-Horn-Carroll (CHC) Ability Definitions Table 4. Select model parameters and fit statistics for WJ III CHC MWg models (see Figure 4) Figures Figure 1: Major stages in the evolution of psychometric theories from Spearman’s g to Cattell-Horn-Carroll (CHC) theory Figure 2: Hypothesized speed hierarchy based on integration of Carroll (1993) speed abilities with recent research Figure 3: Working memory-to- complex cognitive abilities (viz., g and Gf) causal models reported from 1993-2003 Figure 4: WJ III CHC information processing MW-to-g causal model (ages 14-19)