Though from experience talking with people who work in admissions at "selective" schools, SAT scores and grades are mainly used to filter out the bottom 90% of non-preferred (e.g. not athletes, legacies/donors, or geographic/demographically desirable) applicants and the rest is extremely subjective and/or random, and is influenced by many non-academic factors such as whether you are too similar to some already-accepted applicant, etc..
If you are rejected it often has nothing to do with your qualifications so it should not be taken as a negative judgment of same; similarly, if you are accepted often it's often due semi-random factors that placed you ahead of students with better qualifications.
Though from experience talking with people who work in admissions at "selective" schools, SAT scores and grades are mainly used to filter out the bottom 90% of non-preferred (e.g. not athletes, legacies/donors, or geographic/demographically desirable) applicants and the rest is extremely subjective and/or random, and is influenced by many non-academic factors such as whether you are too similar to some already-accepted applicant, etc..
If you are rejected it often has nothing to do with your qualifications so it should not be taken as a negative judgment of same; similarly, if you are accepted often it's often due semi-random factors that placed you ahead of students with better qualifications.