The SAT is a test for the students in the U.S.A. for the purpose of college entrance.
Usually, universities in the U.S.A. requre the TOEFL scores, but some high-rank ones measures students with the SAT.

Therefore, it is needless to say that the SAT is important as much as the high school record. Actually, it can be a standardized exam for measuring students different from high school records which are calculated by a little bit different standards according to high schools. The SAT which has been offered since 1926 had a change that it started to include subjective questions in it.

The first changed test was offered on March 19th, 1994. In fact, the ETS(Educational Testing Services) takes charge of the SAT comissioned by The College Board.