To interpret student performance on the easyCBM measures, one compares a student's raw score on a given measure to the percentile rank associated with that score. This information can be found by comparing the student's score to the percentile rank lines on the individual student report graphs, by hovering over a raw score in the Benchmark Report table, or by referring to the PDF “Interpreting Progress Monitoring Scores” and the Detailed Percentiles chart. In all cases, this information gives an indication of how a student is performing relative to the performance of other students on that measure at that point in time.
Performance at the 50th percentile rank can roughly be interpreted as 'average' performance for students in that grade on that measure at that point in time. Performance below the 50th percentile rank indicates that a student is performing below average on that measure at that point in time, with lower scores indicating performance further below average grade level performance.