The thing is that the MAP and the WJ-III are of the go-until-you-can't-do-anymore variety, so one would expect a GE on one of them to be real--meaning that the 4th grader with a GE of 8.9 (94th percentile as compared with 4th graders) will have taken essentially the same test as the 8th grader with the GE of 8.9 (50th percentile as compared with 8th graders). My kids get the same GEs on these types of tests as they do on the ITBS/ITED. While this is admittedly a small sample size, I do believe that the test makers actually design the tests so that they will correlate fairly well with one another. All of these tests are attempting to measure the same reality and so you would expect the correlation.
What I've found is that *mastering* the material at a particular level (and not knowing any more than that) seems to correspond to placing in the 90th percentile and above for that level.
I haven't had time to go try to find norming sample info for any of these tests yet, but these two quotes of yours suddenly popped into my mind. Wouldn't these two observations contradict one another? If a kid can get a 90th percentile+ score on the 4th grade ITBS, for instance, by knowing nothing beyond 4th grade material (which I agree with b/c I've seen that as well), I'd expect the GE for that 4th grader to be something like maybe 6th grade. So, if we then give that 4th grader the 6th grade ITBS, I wouldn't expect him to get a 50th percentile score for 6th grade b/c he knows little to nothing beyond 4th grade material. Am I making sense here, lol?
This is becoming rather esoteric!
