From the Quantile Framework for Mathematics
With Quantile measures being reported from a growing number of assessments and instructional products, many students receive multiple Quantile measures each year. You may find that a student’s Quantile measures vary significantly within a product or when comparing Quantile measures from different assessments, such as comparing results from a benchmark local assessment with a state end-of-grade assessment. You might be unsure why these test results fluctuate, which of the measures to use to guide instruction, and how to explain this phenomenon to parents.
Why do these fluctuations occur in test results?
Test results offer an estimate of a student’s ability. It’s normal to see a student’s tested measures go up and down. Each test result is just one data point at one moment in time and susceptible to a host of factors that impact test performance. Just as measurements like weight and blood pressure can fluctuate based on a variety of circumstances, so too can test scores.