I am not an educator so I do not know for sure, but from what I understad NCLB actually does a disservice as far as G/T go.

Our school post as % of kids who are at a proficient level, above proficient or below proficient. So having a kid that scores 100% or close to gives them the credit for only that one kid.
Iowa test are different, as they look at the whole class as a group, so a high scoring kid brings a percentage up.