This is really fascinating reading-- thank you for posting all of this, Cricket!
Our district uses a mixture of achievement tests and group ability testing to ID kids. (Why they bother, I don't really know, since anything 90th percentile on either one qualifies as "gifted" here and since that is some 30% of students, they don't really differentiate beyond that anyway, but I digress.) Our distribution here has a median of about 118, I think, which is quite high, no doubt. But it is also bimodal-- there is a regular distribution that centers at 106 or so (the state mean), and then one that centers at about 125-ish. Even so, the latter is a pretty sharp spike that encompasses (surprise, surprise) about 30% of the kids in the district. LOL. Not that it's exactly the same 30% who are ID'ed, but it's close to identical, give or take maybe 5-8 kids from that wider regular distribution.
I'm not sure what those numbers look like if they include things like WISC instead of OLSAT/CogAT.
Even so, kids like my DD are evidently quite rare-- and teachers/administrators know and acknowledge that just on the basis of her functional achievement and demeanor in person-- we have pretty much never offered outside testing but for once, and that was fairly informal and we were up front about that. Her achievement score composites are always 98-99+, but when you realize that those are 3y out of level, effectively, because of her grade accelerations...
well. We learned a long time ago that "gifted programming" isn't intended for HG+ children at all.
I, too, wonder at how such evaluations must (based on what we've seen ourselves with our DD) punish divergent thinking and reward high SES and exposure to concepts, ideas, and activities.
I also wonder whether or not ANY IQ test-- meaning either group or individual-- actually has a lock on anything other than some proxy for that quality that we'd all really like to be measuring with those tools. I seriously doubt it. But I wonder what each one DOES actually capture. It's perhaps some facet of the real (though elusive) thing, but only one facet-- which is just, as someone else noted above-- a "snapshot," and maybe it's not even a snapshot of the entire thing.
