I think GAI exists because processing speed and working memory are so disconnected from other measures of intelligence. As much due to the inadequacy of the tests as actual operational abilities being disconnected from other mental abilities. If a kid is scoring near average on those, I personally don't think it should be an area of concern. Below average then I'd think it has diagnostic value.
Zen, a score near average on PSI or WM for a child who's PRI and/or VCI are high can be extremely significant in terms of how that child functions academically. For other kids, it's possible it doesn't mean a thing - the key is how the student is functioning overall, not just on the WISC tests, and also in understanding why the scores are relatively low, which is why neuropsych evals include additional testing beyond IQ and achievement.
So yes, a score near-average on PSI or WM isn't in and of itself something to be concerned about, but most of us who are posting here with kids who have high VCI/PRI and "average" PSI/WM also have other concerns - our kids are either struggling with schoolwork, behavior issues, etc - and there is something that's up that's behind those challenges. Whatever it is that's behind the issues will sometimes cause a PSI or WM score to be low relative to other scores, and although it's not the *cause* of the issue, it's often the first "data" showing there is an issue and the dip in scores can be very significant. The issue isn't an "average" PSI/WM, the issue is a challenge which is *reflected* in a dip in PSI/WM.
polarbear
