Achievement testing definitely helps if the scores are in the right range. You can often get achievement testing done a lot less expensively than IQ testing. It doesn't hurt to check at the local university or even ask your school. A psychologist does not have to administer achievement testing. I think you can just provide the GAI if the psychologist did not, but make sure it is accurate, of course. Portfolios work for some and not for others. I think it just becomes a little trickier, because people often are unsure over what exactly Davidson is looking for. If you are submitting a portfolio, make sure the work demonstrates the ability to work two to three grade levels ahead. In our case, I sent in WISC scores, two sets of achievement testing scores, and a couple of math tests from school where dd had shown her work. I tried to cover all bases.
