I'm still digesting DD6's test results (and her school's disinterest therein) and am realizing late that she may have hit the ceiling on some WISC subtests. This is one area of testing I haven't explored at all and I'm unsure if it really matters (see school disinterest, above). Thanks to aeh I know that her GAI was miscalculated, so I have to go back to the tester, regardless. The subtests I'm wondering about are: similarities 19; picture concepts 19; vocabulary 18; and letter-number 18. Many thanks.

Yes, I think you should definitely ask about extended norms!

I would. Do you have raw scores?

No raw scores, unfortunately. If I get those from the tester, would I be able to do the calculations myself?

I can do them for you. PM me.

ETA: actually, you can do them yourself, although I'm still happy to look them up for you, if you like. Tables are here:

http://images.pearsonclinical.com/images/assets/WISC-IV/WISCIV_TechReport_7.pdf

Thanks, aeh. My tester has kindly calculated them for me and fixed the GAI typo. Similarities stayed at 19, but Picture Concepts changed to 22. Am I right that I would add the 22, not the scaled score 19 when calculating the GAI? The percentile appears to remain >99.9, regardless.

Yes. The percentile would not really go up in the tables, as >99.9 is the highest it goes. I see that the GAI went up by 4 points, which might matter for some placement cutoffs, but is qualitatively not that different.