Percentile rank
Last updated
A percentile rank tells the percent of students in the norm group who scored at or below a student's score.
Topic: Evaluation and assessment
In plain terms
A percentile rank of 25 means the student scored as well as or better than 25% of same-age or same-grade students. It is not the percent of questions answered correctly. Percentiles are easy to explain to families but are not equal steps: the difference between the 50th and 60th percentile is much smaller in skill than the difference between the 1st and 10th.
How it shows up in an IEP
Percentiles often appear in screening and evaluation summaries. They are useful for describing where a student stands, but should not be the goal criterion, because a percentile can stay flat while skills grow.
Example
A parent sees "16th percentile" and thinks the student got 16% right. The teacher explains it means the score matched or beat 16 of every 100 students in the comparison group.
Not the same as Percent accuracy
Percent accuracy is the share of items correct. A percentile compares the student with other students. Read the definition of Percent accuracy.
Related terms
- Standard scoreA standard score shows how far a student's test result is from the average of the norm group, usually on a scale where 100 is average.
- Norm-referenced testA norm-referenced test compares a student's score with the scores of a large group of same-age or same-grade students who took the test earlier.
- Universal screeningUniversal screening is a brief assessment given to all students, usually three times a year, to find those who may need extra support.
- Grade equivalentA grade equivalent is a score that matches a student's raw score to the grade level at which an average student earned the same raw score.
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