[krapht]

Most students do not have a normal high-school graduation exam. Neither is there a national US school curriculum. Therefore, it is difficult to compare GPAs between students from different school systems.

The SAT is also a thinly disguised IQ test, so it serves a different purpose anyway compared to high school grade records.

A lot of people have strong feelings against the SAT, but I actually think it's somewhat egalitarian. Before the SAT, prestigious colleges would only recruit from well-known feeder high schools whose curriculum was known to be rigorous. Since there is no unifying national curriculum, something like it is necessary so students from worse high-schools have a shot at getting into the nicer universities.