It seems a little unfair that they have to be performing several years above level, given that in a normal class-room they are given no opportunity to do so. Not everyone has the time, resources or skills to make up for the teaching they are not getting at school and even the brightest kids need some help. I am not in the US so it is an academic point but for the life of me I can't work out what the kids 2 - 3 years ahead are supposed to be able to do.