From my limited perspective, staying on-task to complete the SAT or ACT is the biggest indicator of whether a student will be successful in college. Out in life, an employee has many deadlines to complete and they have to write and communicate clearly. That's why being able to write papers is so important. I am surrounded with PhDs and only a few can speak well. However, they understand the information and oversee the work product. No test is going to account for that.