This article explains what percentile rankings are, how they can be used and their limitations.
A percentile is a relative measure that compares a student’s performance on an assessment to the achievement of a comparison group. For many assessments, the comparison group is a representative sample of students in the same year level. If a student is given a percentile rank of 50, you can be confident that this student performed at about the same level or better than 50% of the students in the comparison group. This, of course, also means that the student performed at a lower level than the other 50% of students. A student with a percentile rank of 50 is right in the middle of the distribution for their year level.
Related articles:
- What are percentiles? [Video]
- What are norms? [Video]
- What are the differences between norms and reference groups?
Being a simple comparison measure, percentiles do not provide insight into the skills and knowledge a student has demonstrated. In order to understand student achievement in real terms, students' scale score and achievement band results are more helpful.
Related articles:
- Scale scores and achievement bands
- What are Progressive Achievement scales? [Video]
- What are achievement bands? [Video]
Percentiles and other comparisons between groups of students are not suited to measuring or communicating learning progress over time. In the course of their time at school, a student’s percentile rank within a learning area may not change very much, but they may still be demonstrating growth against the PAT scale. For example, a student who achieves a percentile rank of 50 for PAT Maths in year 2 may also be in the 50th percentile in year 3 while actually having increased their scale score achievement from one assessment to the next.
Related article: What does student progress look like? [Video]