My ds6 had this recently - a couple months ago - done by the school psych along with the WJ achievement testing as part of the evals leading up to his latest IEP.
She never did give me a final IQ number, though I don't really care at this point (he's still developing at a rapid rate; long story. very late bloomer). I didn't care much for the way the test is organized - it seemed like some subtests relied too much on things that belonged in other sections (like working memory and processing speed). See Hoagies re: this test - mentions that it's a bit heavy on auditory processing abilities.
Oddly enough, ds scored significantly higher (about a standard deviation higher) on the WJ achievement test than he did on the cognitive. In part, he's very rapidly developing and there was a few weeks between the tests. But still, it doesn't make sense. The psych had no answer as to why. I suspect it was not a test that suits him well. When I have him tested privately down the road, I'll probably be looking to do the WISC or the SB-5.
If you search this site, you'll find a post by me asking much the same question, and I recall that the WJ cognitive may be much better at finding LDs (which was why it was given to my ds) than at finding an accurate IQ score with regard to giftedness. here it is
http://giftedissues.davidsongifted....hievement_vs_IQ_quick_que.html#Post41907The school psych started to throw around comments about the WJ cognitive as being the only one that relies on some particular theory of intelligence, i.e., in her opinion it's somehow a true-er IQ test than the others, but that's not what other stuff I read said (someplace I read something indicating that it relies on a theory of intelligence that's not as accepted as whatever underlies the other IQ tests).
