Use percentiles and score range to interpret scores
Percentiles compare a student's scores to those of other students who took the test. The number, between 1 and 99, tells what percentage of students earned a lower score. Percentiles are based on the most recent scores earned by current-year college-bound seniors who took the test at any time during high school.
For Subject Tests, percentiles are given for the nation. A student's percentile changes depending on the group he is compared with. Because the national group is larger and more diverse than the state group, the national and state percentiles may be different. Because different groups of students take different Subject Tests, a Biology percentile, for example, cannot be compared with a Literature percentile.
No single numerical score can represent knowledge of a particular subject exactly. The score range presents a better picture of a student's performance. It provides an estimate of how a student's scores might vary if he were tested many times.
If a student had taken the same test or a different version of the Subject Test on another day, his scores would likely vary. Most of the time, the score would fall in a range about 30 to 40 points above or below a student's true ability.
How can I tell if one student performed better than another on the Subject Tests?
There must be a difference of at least 60 points between two students' scores in order for there to be a true difference in ability.
Do Language Subject Test average scores include the scores of native speakers of the language?
Native speaker scores are grouped with those of students who have had less exposure to the language. This means that even students with high grades in language courses may not score as high as native speakers do. Data tables that exclude scores of native speakers are available so you can compare the two groups.