Pending legislation and positions taken by the U.S. Department of Education may radically alter current learning disabilities (LD) definitions and diagnostic approaches. Proposals include eliminating a discrepancy model and incorporating a more comprehensive approach to LD assessment but one based on more subjective clinical judgment. Although this effort to change is laudable, it does not address the residual problems that will continue to plague the field: the lack of specificity of the construct of LD and the inconsistent and idiosyncratic approach to diagnosis taken by practitioners and researchers across and within states. This article proposes a new LD classification model that transcends educational and psychiatric systems of diagnosis, calls for a uniform and national diagnostic system, and suggests renaming the disorder (e.g., developmental learning delay). STEFAN C. DOMBROWSKI received his PhD in school psychology from the University of Georgia and received his MBA from the University of Connecticut. He completed a postdoctoral fellowship in child-clinical psychology at the University of California, Davis, Medical Center. He is an assistant professor in the school psychology program at Rider University. His research interests include child maltreatment and the investigation of the impact of prenatal factors on later child psychological development. He also conducts research on assessment-related issues as they relate to the developmental well-being of children. RANDY W. KAMPHAUS received his PhD in school psychology from the University of Georgia. He is department head and distinguished research professor of educational psychology at the University of Georgia. His research interests include psychological assessment and classification.
The factor structure of the 16 Primary and Secondary subtests of the Wechsler Intelligence Scale for Children-Fifth Edition (WISC-V; Wechsler, 2014a) standardization sample was examined with exploratory factor analytic methods (EFA) not included in the WISC-V Technical and Interpretive Manual (Wechsler, 2014b). Factor extraction criteria suggested 1 to 4 factors and results favored 4 first-order factors. When this structure was transformed with the Schmid and Leiman (1957) orthogonalization procedure, the hierarchical g-factor accounted for large portions of total and common variance while the 4 first-order factors accounted for small portions of total and common variance; rendering interpretation at the factor index level less appropriate. Although the publisher favored a 5-factor model where the Perceptual Reasoning factor was split into separate Visual Spatial and Fluid Reasoning dimensions, no evidence for 5 factors was found. It was concluded that the WISC-V provides strong measurement of general intelligence and clinical interpretation should be primarily, if not exclusively, at that level. (PsycINFO Database Record
The factor structure of the Wechsler Intelligence Scale for Children-Fifth Edition (WISC-V; Wechsler, 2014a) standardization sample (N = 2,200) was examined using confirmatory factor analyses (CFA) with maximum likelihood estimation for all reported models from the WISC-V (Wechsler, 2014b). Additionally, alternative bifactor models were examined and variance estimates and model-based reliability estimates (ω coefficients) were provided. Results from analyses of the 16 primary and secondary WISC-V subtests found that all higher-order CFA models with 5 group factors (VC, VS, FR, WM, and PS) produced model specification errors where the Fluid Reasoning factor produced negative variance and were thus judged inadequate. Of the 16 models tested, the bifactor model containing 4 group factors (VC, PR, WM, and PS) produced the best fit. Results from analyses of the 10 primary WISC-V subtests also found the bifactor model with 4 group factors (VC, PR, WM, and PS) produced the best fit. Variance estimates from both 16 and 10 subtest based bifactor models found dominance of general intelligence (g) in accounting for subtest variance (except for PS subtests) and large ω-hierarchical coefficients supporting general intelligence interpretation. The small portions of variance uniquely captured by the 4 group factors and low ω-hierarchical subscale coefficients likely render the group factors of questionable interpretive value independent of g (except perhaps for PS). Present CFA results confirm the EFA results reported by Canivez, Watkins, and Dombrowski (2015); Dombrowski, Canivez, Watkins, and Beaujean (2015); and Canivez, Dombrowski, and Watkins (2015). (PsycINFO Database Record
This study investigated the factor structure of the Reynolds Intellectual Assessment Scales (RIAS) using rigorous exploratory factor analytic and factor extraction procedures. The results of this study indicate that the RIAS is a single factor test. Despite these results, higher order factor analysis using the Schmid—Leiman procedure indicates that all subtests are aligned with their theoretically consistent factors. All analyses in this study, including the minimum average partial test, parallel analysis, the Schmid—Leiman procedure, as well as principal factors with orthogonal and oblique rotation, support interpretation at the composite intelligence index level and suggest caution when moving to interpretation at the verbal and nonverbal index levels. The memory subtests should continue to be separated from the main IQ battery because of poor g-loadings and contribution to cross loadings of the intelligence subtests. Interpretation at the subtest level should be eschewed.
Development of the Woodcock-Johnson (3rd ed.; WJ-III; Woodcock, McGrew & Mather, 2001a) was guided in part by Carroll's (1993) 3-stratum theory of cognitive abilities and based on confirmatory factor analysis (CFA), even though Carroll used exploratory factor analysis (EFA) to derive his theory. Using CFA, McGrew and Woodcock (2001) found a 9-factor model across all age ranges. To determine if the 9-factor structure holds for the full WJ-III battery, we applied currently recognized best practices in EFA to 2 school-aged 42-subtest correlation matrices (ages 9–13 and 14–19 years). Six factors emerged at the 9–13 age range, while 5 factors were indicated at the 14–19 age range. The resulting 1st-order factors displayed patterns of both convergence with and divergence from the WJ-III results presented in the Technical Manual. These results also revealed a robust manifestation of general intelligence (g) that dwarfed the variance attributed to the lower order factors. It is surprising that this study represents the first time the WJ-III full battery was subjected to EFA analyses given the instrument's significant use by practitioners and that it served as the initial evidentiary basis for Cattell-Horn-Carroll (CHC) theory. The lack of confirmation of CFA results with EFA methods in the current study permits questioning of the structure of the WJ-III and its relationship with CHC theory. Additional independent, structural analyses are clearly indicated for the WJ-III full test battery before we can be confident in its structure.
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