a variety of theories attempt to explain intelligent human behavior (Sternberg &
Kaufman, 1998), the most influential approach, and the one that has generated the most
influential research, is based on psychometric testing (Neisser, Boodoo, Bouchard, Boykin,
Brody, Ceci, Halpern, Loehlin, Perloff, Sternberg & Urbina, 1996, p.95). The Cattell-Horn-
Carroll (CHC) theory of intelligence is the tent that houses the two most prominent psychometric
theoretical models of human cognitive abilities (Daniel, 1997, 2000; Snow, 1998; Sternberg &
Kaufman, 1998). CHC theory represents the integration of the Cattell-Horn Gf- Gc theory
(Horn & Noll, 1977) and Carrolls three-stratum theory (Carroll, 1993, 1997). CHC is
psychometric theory since it is primarily based on procedures that assume that the structure of
intelligence can be discovered by analyzing the interrelationship of scores on mental ability tests.
To develop these models, large numbers of people are given many types of mental problems.
The statistical technique of factor analysis is then applied to the test scores to identify the
factors or latent sources of individual differences in intelligence (Davidson &
psychometric study of cognitive abilities is more than the exploratory factor analysis of a set
of cognitive variables. Contemporary psychometric aproaches differ from traditional
psychometric approaches in three major ways: (1) a greater use of confirmatory (vs.
exploratory) factor analysis methods, (2) the structural analysis of items is now as important as
the structural analysis of variables, and (3) item response theory (IRT) models now play a pivital
role (Embretson & McCollam, 2000). Space limitations necessitate a focus only on the factor
analytic portions of the contemporary psychometric approach. It is also important to recognize
that non-factor analytic evidence, in the form of heritability, neurocognitive, developmental, and
outcome prediction (occupational and educational) studies, provide additional sources of validity
evidence for CHC theory (Horn, 1998; Horn & Noll, 1997).
This document dedicated to the memory of John Jack Carroll, grandmaster of quantitative
cognitive science (Jensen, 2004, p. 1). The author would also like to thank Jeffrey Evans for
in the literature review for this chapter.]