Mike Bay

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Cognitive assessment is an important domain in psychology. The development of nonverbal cognitive assessment devices has been spurred by the increasingly multicultural nature of U.S. society and by legislation calling for early identification and treatment of children with cognitive disabilities. The Leiter-R is a non-verbal test of intelligence designed chiefly for use with language-and cognitively-impaired persons aged 2-21. Exploratory factor analysis (EFA) of the Leiter-R was undertaken in an effort to (a) identify the factor structure of the Leiter-R, (b) verify general visualization (Gv) and fluid reasoning (Gf) as second-level factors in the Leiter-R, and (c) examine evidence for the hypothesis that cognitive abilities become increasingly differentiated with age. The EFA revealed a strong g influence in the Leiter-R, with one-factor model s predominating in each age group studied. General-factor loadings of four core Leiter-R subtests (those subtests common to all age groups) indicated subtests vary in how well they measure g among different age groups. Overall, these results are judged to support the Leiter-R as a g test of intelligence. In contrast to the findings of other researchers (Bos, 1995; Bos, Gridley, & Roid, 1996), only modest evidence was found to verify Gf and Gv as second-level factors in the Leiter-R . However, analyses of certain age groups offered some evidence of a two-factor structure . This evidence offered support for the Leiter-R 's theoretical structure, with separate Gf and Gv factors in the 2-5 age group and a distinct spatial visualization factor emerging in the 6-10 and 11-21 age groups. Little conclusive evidence was found for or against the age differentiation hypothesis. Limitations of the present study were noted, most importantly that not including all Leiter-R subtests in the analysis, which was done for statistical reasons, may have made it more difficult to extract factor structure. Ideas for future research were presented. At the time of this writing, research related to the Leiter-R is ongoing. Final factor analyses of the Leiter-R--using the larger final normative sample, including memory and attention subtests , and perhaps using hierarchical factor analytic methods- -may help further reveal characteristics of the Leiter-R 's factor structure.