Rankings go from 1 to 99. Each percentile rank is read in two ways. First, the number listed represents the percent of the national group that performed at or below that ranking. Second, the number represents the middle, or median, ranking for a school population. The numbers on the tables of school percentile rankings are medians.
Medians are the middle rank for the group being reported.
This means that half the students at a school ranked above the number shown and half ranked below that number. Since rankings go from 1 to 99 the national center point, or median of the scale, is 50. Fifty is the expected ranking for large groups of students. For small school groups, median percentiles are not as stable and are not always expected to be 50. Inclusion in regular testing is intended to give information on how a special education student performs on district or state curriculum.