Because so many students at the top universities have great ACT or SAT scores, I do recommend that students *consider* Subject Tests. You’ll only want to worry about them if you think that they can improve your testing portfolio. In the case of elite schools like Columbia, that means 750+ (or at least 700+). You can try tests from the Official Guide published by College Board. Fewer schools than ever are requiring the Subject Tests — especially with ACT scores. It would be a little challenging to fit them in (including preparing for them) as senior year starts and application season begins, so you may want to just sit tight with your ACT score.