A visual representation of the third method SLD models as presented by Flanagan & Fiorello, 2010) is below. [Click on image to enlarge]
These results are derived from my art+science exploratory data analysis of the WJ III norm data guided by the findings from McGrew and Wendling (2010). Analyses included (a) multiple regression prediction of two reading and two math achievement subdomains (only two are featured here) with selected subsets of WJ III cognitive tests (using backward elimination of variables one-at-a-time; many eliminated tests re-entered at end to insure they were still not significant predictors that should have been retained in the final model), (b) calculation of all cognitive test g-loadings via first unrotated principal component across ages 6-18 years, and (c) multidimensional scaling (MDS--Guttman Radex model) of the complete set of WJ III cognitive predictors.
Visual graphic summaries are presented in hopes of stimulating thoughts about how these presentation methods might be used to allow examiners to engage in intelligent selective referral focused assessment decision-making grounded in data (but the numbers are minimized on purpose), theory, and logic.
Conflict of interest warning. I am a coauthor of the WJ III.
Click on images to enlarge.
Conceptual link between third method approaches and above slides follows.
MDS illustrative model.
Conceptual link between the three preceding slides and third method SLD models
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