I am starting a new thread on this topic following the topic having come up on a number of threads including this one: http://giftedissues.davidsongifted.org/BB/ubbthreads.php/topics/157401.html#Post157401

A few posters here have mentioned actual studies that show the CogAT to be a poor predictor of giftedness, but no one has posted any actual studies to my knowledge. The only one I had seen was the old one from the 1980s that I posted in the above referenced thread on the OLSAT vs. the WISC-R.

I have found a few others though, although they are not available in their entirety online as far as I can tell. Here's what I've got thus far:

An Examination of the Relationship Between the WISC-III and the Cognitive Abilities Test for Selection of Students for a Gifted Program - this appears to be an 84 page dissertation with the following excerpt/abstract:

Quote
The present investigation compared the Wechsler Intelligence Scale for Children, Third Edition (WISC-III) and the Cognitive Abilities Test (CogAT) scores for 12 children who were placed in a gifted program. A comparison of the correlations using the Pearson product-moment correlation showed no significant correlation between these measures. A correlated t test showed no significant mean difference between these measures on the Performance and the Full Scale IQ means. Significant difference was found on the mean IQs of the Verbal section of these instruments. Implications concerning the study are discussed.
http://books.google.com/books/about/An_Examination_of_the_Relationship_Betwe.html?id=mX5cOAAACAAJ

The Woodcock-Johnson III and the Cognitive Abilities Test (Form 6): A concurrent validity study - pdf available in its entirety online here: http://faculty.education.uiowa.edu/docs/dlohman/CogAT_WJIII_final_2col-2r.pdf

with the following abstract,
Quote
This study investigated the concurrent validity of the Woodcock-Johnson III (WJ-III; Woodcock, McGrew, & Mather, 2001) and Form 6 of the Cognitive Abilities Test (CogAT; Lohman & Hagen, 2001). A total of 178 students in grades 2, 5, and 9 were administered 13 tests from the WJ-III and the appropriate level of the CogAT. Interbattery confirmatory factor analyses showed that the general factors on the two batteries correlated r = .82. Correlations between broad-group clusters on the WJ-III and battery-level scores on the CogAT generally supported the construct interpretations of each, but also suggested important differences in the abilities measured by both batteries.


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