How do colleges use your ACT score?
The most important score is typically the Composite score (which is an unweighted average of the four major subject scores). This is the score used by most colleges and universities in the admissions and scholarship process. The subject scores and subscores may be used for advanced placement or occasionally for scholarships, but they are primarily used by college advisors to help students select majors and first-year courses.
Although many schools deny that they use benchmark scores as cutoffs, students have had mixed experiences, and it's well worth understanding the impact of all of your scores. Highly competitive universities generally decline to accept students with any Composite scores below 22 or 23. For less competitive schools, the benchmark score may be lower than that; for some very selective schools, the cutoff may be higher.
To be clear, no school uses the ACT as an absolute or stand-alone bar to admission; for most applicants, though, a low ACT score can be decisive. As a rule, only students whose backgrounds are extremely unusual or who have overcome enormous disadvantages are accepted if their ACT scores are below the school's benchmark.