Student Growth Percentiles (SGP) measure students’ progress compared to academic peers. They are calculated using data from statewide assessment tests, comparing students’ scores on these tests with the scores of their academic peers across the state. This data can be used to identify high performing students, schools and districts. It can also be used to analyze trends in performance and make decisions to improve student learning.
The SGP data are derived from MCAS testing in grades 4, 5, 6, 7, 8, and 10 in all public schools and some private and charter schools. Each year, the data are recalculated to reflect new test results and a student’s academic peer group for that grade. These recalculated SGPs are reported to each district and school in the fall. Districts then submit the SGP data to their local data system, where they are available for analysis by schools, teachers and parents.
SGPs can be compared over time for individual students, schools, and districts. The average SGP statewide will always be approximately 50 (+/-1) because the scale is normative and consistent from year to year. However, individual SGPs for specific students can vary from year to year because the data are based on smaller samples of students.
Students that score at the top of the MCAS scale will generally have higher growth than students with lower scores, but even students that are at the very top of the scale can experience different levels of growth from year to year. This is because student achievement is a result of both teacher instruction and individual differences in students.
Each year, the state’s SGPs are revised based on changes to the student demographics and a review of the underlying assumptions of the model. The revisions to the model can lead to shifts in the overall distribution of student growth percentiles. In some years, a large portion of the state’s students may experience more or less growth in their academic skills than normal, as was the case during the Covid-19 pandemic.
The SGPdata package contains 4 examplar data sets for use with SGP analyses. One of the data sets, sgpData, specifies data in a WIDE format that’s used by the lower level SGP functions studentGrowthPercentiles and studentGrowthProjections. The other data sets, sgpData_LONG and sgptData_LONG, specify long format data and are utilized by higher level SGP functions such as abcSGP and prepareSGP.
The final data set, sgpData_INSTRUCTOR_NUMBER, is a teacher-student lookup table that’s utilized by the higher level SGP function analyzeSGP to produce teacher-level aggregates. The SGP data can be downloaded from the MLN Data Downloads page. Please note that the data sgp are not currently available for Science, EOC Biology, and EOC Math. These data will be available in the fall of 2021. Until then, the data should be used with caution and only differences in SGPs that are at least 10 points can be interpreted.