Thursday, October 23, 2008

WISC-III/WJ III cross-battery Guttman 2-D Radex analysis

One more WISC-III/WJ III cross-battery analysis--this time a 2-D Guttman Radex MDS model (click here).  As readers have noted, I've been on a bit of a data analysis binge this past week (in preparation for writing a manuscript---and after being refreshed by an actual 2+ week vacation) and have reported:  (a) WISC-III/WJ III cross-battery g+specific cog-ach relations SEM, (b) WJ III 2-D Guttman Radex MDS of WJ III norm sample ages 6-8, and (c) WJ III 3-D Guttman Radex MDS of ages 9-13 of norm sample.  It is hoped these analyses provide useful information in understanding the characteristics of the tests in the WJ III and Wechsler intelligence batteries.

Unfortunately this analysis is based on the WISC-III and not the more recent WISC-IV.  Nevertheless, the results still provide useful information on the WISC-III tests that are still present in the WISC-IV.

Given all I've written regarding the various MDS models, I'm going to only make a few comments and hope others take the presentation of these data to engage in additional discussion, interpretion, etc.----have some fun.

A few observations/comments:
  • Gv tests (both WISC-III and WJ III) continue to surface on the more outer rings of the MDS models---suggesting that they are more lower-level perceptual/processing measures and do not capture complex Gv cognitive processing.  See my Gv comments on this the other day.  The same can be said for Ga tests.
  • WJ III Understanding Directions is consistently one of the more cognitive complex tests.  And, it is largely a language-based measure of working memory (Gsm-MW).  Remember that as per the Radex model, cognitive complexity deals with the amount of elements/components that are processed.....and is not the same as abstract thinking (Gf-ish stuff).  WJ III Numbers Reversed also shows up close to the center, with WISC-III Digit Span not far behind.  Does this support the popular working memory=Gf/g research hypothesis?
  • The Gc tests from both batteries appear similar in placement.
  • As would be expected, the WJ III Gf tests (Concept Formation, Numerical Reasoning [which is a combo of Number Series and Number Matrices], and Analysis-Synthesis are within the center "cognitive complexity" circle.
I'm sure there is much more that can be gleaned, but I'll leave that to the readers to discover, debate, and discuss.  I actually think a 3-D MDS model is necessary to capture the characteristics of the measures...but I've run out of time and steam on these analysis.  Maybe at a later date.

A couple caveats I provided the other day are also relevant here--(a) I'm a coauthor of the WJ III (conflict of interest disclosure) and (b) these results have not been peer-reviewed

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