From Inside Higher Ed:
The largest study of students at colleges that do not require SAT or ACT scores has found that there is “virtually no difference” in the academic performance (measured in grades or graduation rates) of those who do and don’t submit scores.
The study — involving 123,000 students at 33 colleges and universities of varying types — found that high school grades do predict student success. And this extends to those who do better or worse than expected on standardized exams. So those students with low high school grades but high test scores generally receive low college grades, while those with high grades in high school, but low test scores, generally receive high grades in college.