The norms (percentile rankings relative to raw scores) change from season to season. The benchmark raw score/percentile ranks match up by quarter. If you look at the Detailed Percentiles Table or the Progress Monitoring Scoring Guidelines on the Reports page after logging in, you will see that they are organized by season and match up within a point or so across the seasons. You likely don’t want to think of it by month, but rather season, assuming that between seasonal benchmark administrations that student growth is linear. For example, the benchmarks are roughly: Fall – Sept 15th, Winter – Jan 15th, and Spring – May 15th. If you plotted those out…looking at the individual student graphs, which plot both benchmark and progress-monitoring performance, that is where the lines by percentile (10th, 20th, 50th, etc) come from. They are used to help calculate student goals (e.g., aim lines), and thus, show if a student is growing at a faster (or slower) rate than needed/desired. For example, if a student begins Grade 5 at the 10th percentile, their trend should be steeper, moving toward 20th/50th percentile if he/she is to catch up with their grade-level peers by spring.