Why would you take an SAT II Subject Test? There’s only one reason: colleges want you to, and sometimes require you to.

Colleges care about SAT II Subject Tests for two related reasons. First, the tests demonstrate your interest, knowledge, and skill in specific topics. Second, because SAT II tests are standardized, they show how your skills in math (or biology or writing) measure up to the skills of high school students nationwide. The grades you get in high school don’t offer such a measurement to colleges: some high schools are more difficult than others, meaning that students of equal ability might receive different grades. SAT II tests provide colleges with a yardstick against which colleges can measure your, and every other applicant’s, knowledge and skills.

When it comes down to it, colleges like the SAT II tests because the tests make the colleges’ job easier. The tests are the colleges’ tool. But because you know how colleges use the SAT II, you can make the tests your tool as well. SAT II tests allow colleges to easily compare you to other applicants. This means that the SAT II tests provide you with an excellent chance to shine. If you got a 93 in a math class, and some kid in another high school across the country got a 91, colleges won’t know how to evaluate the scores. They don’t know whose class was harder or whose teacher was a tough grader or whose high school inflates grades. But if you get a 720 on the SAT II Math IIC and that other kid gets a 650, colleges will recognize the difference in your scores.

Time for some perspective: SAT II tests are not the primary tools that colleges use to decide whether to admit an applicant. High school grades, extracurricular activities, and SAT or ACT scores are all more important to colleges than your scores on SAT II tests. If you take AP tests, those scores will also be more important to colleges than your SAT II scores. But because SAT II tests provide colleges with such a convenient measurement tool, they are an important part of your application to college. Good SAT II scores can give your application the boost that moves you from the maybe pile into the accepted pile.

Occasionally, colleges use SAT II tests to determine placement. For example, if you do very well on the U.S. History SAT II test, you might be exempted from a basic history class. Though colleges don’t often use SAT II tests for placement purposes, it’s worth it to find out whether the colleges to which you are applying do.