If you have access to Naviance and your school has had enough applicants to top schools, you can see pretty clearly how it works. At Williams, Amherst, most Ivies, UChicago, MIT, Stanford, Duke and a few more - the admitted students are all above a certain test score and GPA, but after that, the admissions pattern remains scattered. Other factors like ECs and recommendations and essays all clearly play a major part in determining whether you get admitted.
Now there are some competitive schools where test scores seem to matter more than others. For our high school and from what I have heard from others posters on CC, it seems that Vanderbilt, WashU, Tufts, Notre Dame, USC, Northeastern, and some others seem to emphasize test scores more highly. Virtually every applicant with an extremely high SAT or ACT (and good grades) gets admitted to those schools from our high school. ECs, recs and essays don’t seem to matter much at all.
Finally, there are schools that care less about test scores than others. The most obvious examples are UCBerkeley, UCLA and the other UCs, which all emphasize grades, class rank and class rigor more than tests. They want the very top students from every high school in California to get a chance at a UC, even if the school was poor and lousy. They cannot consider race, they don’t care much about hooks, and they don’t have time to carefully evaluate your essays - they have over 100,000 applications to get through. Basically, if you aren’t the very top of your high school class, your 36 ACT won’t get you in, but if you are, your 26 ACT won’t keep you out.
So, the upshot is - if you are aiming for Ivies, Williams, Amherst and similar schools, if you get your test score into the top range, lets say 34-36 ACT or 1500+ SAT, you can stop and worry about other things. If you are aiming for Vandy, WashU, etc., you should maximize your test scores to improve your chances. If you are aiming for UCBerkeley, worry about your grades and class rigor vis-a-vis the rest of your school.
There’s a good place for every good student. You will find yours.