Gifted Issues Discussion homepage Forums Identification, Testing & Assessment .

You have a lot of thoughtful questions here, some of which I may inadvertently not comment on or not get to this round...remind me if something important is missed. Quantitative notes below are all regarding the most current revisions (WISC-V, WAIS-IV).

With regard to one of your initial questions, the correlation coefficient between Si and PC is .39, which is among the lowest correlations for reasoning subtests (as distinct from cognitive proficiency subtests). PC also has the lowest correlation to any of the reasoning Index scores of any reasoning subtest (between .23 and .48, vs mostly .5ish to .8ish for the other subtests). That, of course, is why it is not a core subtest (particularly because of its weaker correlation to the FSIQ). It has the weakest correlation of any non-processing speed subtest.

The NAGC data on performance in GT learners found that the mean PC score was 13.6. That was the lowest mean score of all of the reasoning subtests. FWIW, my experience has been that GT examinees sometimes experience some artifactual penalties on PC because they find other relationships among the stimulus items that are legitimate and logically consistent, but not normative. There seems to be an element of reading "what would typical learners say" to scoring well on it. I've even gone back on testing of limits (clinical inquiry) and prefaced the second exposure with statements of that nature.

( Table 1, using extended norms).

There are various positions on whether Co is verbal knowledge or verbal reasoning. One can make an argument for either. Its correlations are nearly identical to Si (.59) and Vc (.60), which are generally considered the less ambiguous representatives of verbal reasoning and verbal knowledge. Its correlations on the WAIS-IV are slightly more tilted toward Vc, but still not by a ton. Co is also heavily culture-bound, which I would postulate may be part of its uncertain assignment to knowledge or reasoning. If a learner is fluent in the culture, I would suggest that it might be a better measure of contextualized social reasoning (as it is often interpreted to be), but if an examinee is not, then clearly acquired knowledge will significantly impact performance, in which case one might better describe it as an indicator of knowledge of social conventions. (I have used either or both of these interpretive lenses, depending on the larger context of the student.)

Notably, Si and Co were the two highest mean subtest scores in the NAGC's GT sample. (Both 18.1).