I don't think schools respond to reports with scores that "would be higher if...". If you handed the school this, they would reject a skip. You could try with the SB5 if you really feel he needs a skip.
I would second squishy's cautionary note, and add that, in our school district, the set of achievement scores you have would also most likely cause a rejection of a request for a grade skip. What would more likely work is a combination of work products from a classroom (once he's started school), work products from home, an achievement test that specifically tests against school district curriculum standards, and (or in isolation) the recommendation of a teacher. It sounds like you have the recommendation of a teacher, although to be honest, I wouldn't (as a parent) go in with that recommendation with the teacher saying she'd recommend based on having worked with your older dd - you have two different children with potentially two different learning styles and two very different sets of needs.
Re the WIAT, there are a few thoughts I'd consider when using them to advocate - take my thoughts with a grain of salt - my kids have been testing with the WJ-III Achievement tests, which are a different but somewhat similar set of tests. It's possible I might misunderstand something from the WIATs, so don't take my word for anything without a second from someone who's familiar with them.
1) The scores on the WIAT are average to high average with the exception of math - which isn't what most schools are looking for when placing students in gifted programs or considering for grade skip - at least not in the area I live in. You may be able to use the math score to advocate for a math subject acceleration, especially since you also have the higher ability scores in areas related to math skills.
2) The grade equivalent given for these tests is *not* the same thing as saying a child is ready to plop into a classroom at the given grade level. It means that your child's score is the same as the 50th percentile score achieved in a sample of students in that grade level. It is not tied to curriculum and hence has limited relevance for consideration for subject grade placement from a teacher's perspective.
3) Another potential gotcha on the achievement tests is that each subtest assesses a very specific skill set, then subtest scores are averaged together. The benefit of this is that you can see easily where a student's strengths and challenges lie, and the downside can be that a score may come in low for a specific challenge, but in reality that challenge is compensated for in classroom performance and might not be an obvious challenge. OTOH, in the case where one type of skill is a challenge and results in a low achievement test score - you can often remediate or accommodate for that specific skill set and then the child will be able to function very well in an accelerated classroom in that subject if he/she has the innate ability to learn at a higher level in the subject. I think I didn't explain that very well! Sorry... it's early morning here lol. This is an example of what I'm trying to say: My dysgraphic ds writes very slowly. His score on the math fluency subtest on the WJ-III achievement tests is always very slow relative to his WISC score percentiles and relative to other math subtests on the WJ-III. The math fluency subtest is a timed test that measures both ability to do math calculations *and* the ability to write them down quickly. Hence the low score - due to his dysgraphia - which is not related at all to an understanding of or ability to do math calculations. In school he is multi-year subject accelerated in math and has accommodations for extended time on tests and is allowed to keyboard his work.
Anyway, it could be interesting to look at your ds' WIAT subtest scores to see if there is significant scatter.
polarbear
