All students receive a standardized score on a common vertical scale which reveals how the tested students performed in comparison to grade-specific national norms. Such standard scores are known for all grades.


A percentile rank tells what percentage of students in a specific group received lower scores than the student in question. The range is from 1-99.


Each student's score corresponds to a percentile relative to the distribution of other students' scores in the same grade, for a particular month. The percentage of scores at or below a particular value defines scores' percentiles. 


Students with score percentiles near 50 are at the average for the month in which the assessment was taken. Lower percentiles indicate slower overall growth, while higher values indicate accelerated overall growth relative to the nation at large.


The table below shows the Scale Scores at the 10th, 50th, and 90th percentile for grades K-8 in the months of September, January, and May:


     

September
January
May

10th50th90th
10th50th90th
10th50th90th
Grade   
   
   
Kindergarten226390551
279444605
320485645
Grade 1331496657
379544704
415581740
Grade 2425590751
467631792
498664823
Grade 3507671832
542707868
569735894
Grade 4576741902
606771931
628794953
Grade 5634799961
655822983
6758411000
Grade 66808441005
6978621022
7108761035
Grade 77138781038
7258891050
7338991058
Grade 87348991060
7409051065
7449101071