Student Growth Percentiles (SGP) are an additional statistic to consider alongside scaled scores and achievement levels in order to gain a more complete picture of a student’s learning. SGPs report how much a student has grown in academic skills compared to their “academic peers.” Academic peers are all students who have similar previous MCAS test scores and follow a relatively similar assessment score path. These academic peers are selected based solely on their previous test scores, and are not related in any way to demographic groups or educational programs.
An SGP indicates how far a student has progressed toward meeting state standards in a particular subject area compared to their academic peers who have scored similarly on MCAS tests from prior years. This information can be used to help identify if a student has achieved at least average growth, or if they are struggling and need further support.
SGPs are calculated using up to two years of historical MCAS data. For example, an SGP calculated in spring 2024 is based on the student’s performance relative to their academic peers who scored similarly on the 2023 and 2024 MCAS tests. The same academic peers are used in both calculations to ensure consistency between the two years of growth. Academic peers are selected for all students statewide, regardless of demographic group or program participation.
The SGPdata package contains 4 examplar data sets for use with SGP analyses. The first, sgpData specifies data in the WIDE format that’s used with the lower level SGP functions studentGrowthPercentiles and studentGrowthProjections. The second and third data sets, sgptData_LONG and sgptData_LONG_INSTRUCTOR_NUMBER specify data in the LONG format that’s used by higher level SGP functions like abcSGP, prepareSGP and analyzeSGP. The last data set, sgpData_INSTRUCTOR_NUMBER is an anonymized, teacher-student lookup table utilized by higher level SGP functions to produce aggregates for teachers.
A Student Growth Percentile is an estimate of how far a student has progressed towards meeting state standards in a particular subject area (such as math) compared to their academic peers who have also taken MCAS tests. These are the students they are most likely to score well or poorly compared to in future years.
In 2024, an SGP of 60 indicates that a student has scored the same as or higher than 60% of their academic peers in that subject area. This is equivalent to a score on the national PSSA test in grade 8.
It’s important to remember that SGPs are calculated anew each year, so any differences between years should be interpreted with caution. Differences of less than 10 points should generally not be considered meaningful.
SGPs are based on the historical growth trajectories of Star examinees, so they will vary across subjects. This is because different subjects require different amounts of growth to reach proficiency. To get a more accurate sense of a teacher’s SGP, the Star Growth Report should be customized for a specific window. Window specific SGPs can be found by selecting a previous or current school year from the Timeframe drop-down list when creating a Star Growth Report.