A percentile ranking represents how well a student performs compared to other students in a nationwide norm sample for their grade. A student scoring at the 35th percentile scored as well as, or better than, 35 percent of students in the same grade in the norm group. It also means that 65 percent of the students exceeded this score.
A common mistake is for people to think this means that the student got 35 percent of the items correct. Percentile is not related to the percent of correct answers a student gets on a test.
The percentile is not a good method for measuring growth in students. Students who achieve typical growth will remain at approximately the same percentile score over time.