A student’s growth in the classroom is determined by how they perform on a state assessment compared to their academic peers across the state. A student’s statewide median Student Growth Percentile (mSGP) measures their average growth score on a State Assessment in English language arts or mathematics based on the performance of students statewide with comparable test scores from previous years.
SGP scores are calculated for each student following the completion of each year’s statewide assessments in both English language arts and mathematics. Teachers who taught the class for at least 60% of the course prior to the state assessment are assigned a teacher SGP score. This is determined by the districts submission and certification of course roster submission data through NJ SMART in the summer following each year’s statewide assessments.
The sgpdata package provides 4 examplar data sets for use with SGP analyses. The first, sgpData, specifies data in the WIDE format used by lower level SGP functions like studentGrowthPercentiles and studentGrowthProjections. The other two data sets, sgptData_LONG and sgpData_INSTRUCTOR_NUMBER, specify data in the LONG format that’s utilized by higher level functions like abcSGP, prepareSGP and analyzeSGP.
In sgpData, the first column, ID, provides the unique student identifier and the remaining 5 columns, GRADE_2013, GRADE_2014, GRADE_2015, GRADE_2016, and GRADE_2017, provide the student assessment scores associated with each of the 5 previous years. These are typically the only years of assessment available for students who begin in grade 3; students who start in grades 4, 5, or 6 may have additional years of testing depending on the test.
While SGPs are a useful metric for comparing student growth, it’s important to understand that the growth numbers are only as accurate as the current year of the data from which they are being computed. The reason for this is that SGPs are calculated based on trends in the performance of students across the state and country each year. Some years, for example during the Covid-19 pandemic, a large percentage of students experienced less growth than in typical years.
SGPs are also impacted by the fact that students that receive high scores on state tests tend to have the highest growth rates. This is because they are comparing themselves to the best of their academic peers. However, even those students that score at the very top of the scale will see variable growth from year to year.