What are Percentiles and Why Do They Matter?

Any time you read a score report from a standardized exam, particularly a norm-referenced test, you’re bound to see percentiles. Why? Because percentiles explain the rank of a test score in relation to the entire testing population.

Traditional percentiles present scores at a given percentile, where that score is higher than the given percentage of the population e.g., 67th percentile is higher than the scores of 67% of the testing population.

However, the College Board and ACT present scores in a given percentile, where reported scores is greater than or equal to the given percentage of the population e.g., 67th percentile is greater than or equal to the scores of 67% of the testing population.

Percentile distribution on tests like the SAT and ACT correspond to the standard distribution (bell curve) and help test takers and families understand the significance of test scores, especially in relation to levels of college competitiveness. For example, the most competitive colleges usually require scores in the 99th percentile for admission. Considering the arbitrary ranges of the 400-1600 SAT scale and 1-36 ACT scale, a strong grasp of percentiles will help explain the relative and absolute merits of student scores.

Sometimes, though, the test makers clog up their score reports with meaningless and misleading data. The College Board is a prime offender, sharing two different percentile ranks even though only one has value:

• Nationally Representative Sample Percentiles measure against all U.S. students in grades 11 and 12, regardless of whether they take the SAT.
• User Percentiles are based on the actual scores of students in a given graduating class of 2017 who took the SAT.

Obviously, colleges do not care about the test scores of students who do not take a test. Only pay attention to User Percentiles!

COMPARING TEST SCORES
Paying attention to percentiles presents a basis for comparison of SAT and ACT scores. If, for example, a student scores in the 90th percentile on the ACT and the 70th percentile on the SAT, that student is clearly much better on the ACT. Furthermore, that student might be wise to only send ACT scores with her college applications, ignoring SAT scores entirely. College Board and ACT have collaborated on official ACT/SAT Concordance Tables that pair SAT and ACT test scores by percentile ranks.