[dayvid]

I think each school has their own culture/brand they're going for and they want to find the best fit for that brand. Just having the best test takers doesn't match.

Harvard probably wants a mix of people who have a history of going to Harvard, elites, with high performers and others. If it's only elites, then the academic quality goes down. Only best academic performers, elites will go to another school to call home, etc.

[kelipso]

elites == upper class, for those not from the US... Of course that being the reason test scores are considered primary in other countries and not the US. American universities have a need to recruit upper class students for various purposes including keeping the influence of the upper class on government, media, etc going.