The Data SGP Package

The data sgp package provides tools for running operational analyses of SGP related data. The lower level SGP calculations (studentGrowthPercentiles and studentGrowthProjections) require wide formatted data while the higher level functions that wrap these calculations (studentSGPMetrics, teacherSGPMetrics, schoolSGPMetrics) assume sgpData in long format. It is important to have your data prepared in a consistent fashion for all analyses. Almost all problems that come up while analyzing SGP data revert back to issues in data preparation so it is worth taking the time to prepare your data thoroughly before running any analysis.

Student Growth Percentiles (SGP) describe a students growth relative to academically similar peers. The SGP scale ranges from 1 to 99 with higher numbers indicating greater growth. SGPs are calculated based on the historical performance trajectories of Star examinees and are updated frequently to project what a student’s potential future growth trajectories would look like.

SGPs can be aggregated to summarize the growth of subgroups, classes, schools, and districts. Traditionally median SGPs have been used for these summaries representing the middle value of the group. The Department is transitioning to means as the primary summary tool because it aligns better with the guiding philosophy that all students contribute to accountability results.

Educators who have many of their students in the upper half of the mSGP distribution are driving significant academic growth. This is why the Department sets educator ratings based on this distribution. If a teacher has more than half of their students in the top 20% of the mSGP distribution they should be considered an elite educator. However, if they have many students in the bottom 20 percent of the mSGP distribution it is an indicator that their teaching is not helping their students make adequate progress.

Each year the State Board of Education releases a set of reports to provide statewide and school level information about student performance. These reports include a variety of different statistics such as student achievement, enrollment, graduation rates and more. In addition, the State Board of Education releases student growth reports comparing one year to the next. These growth reports use the SGP scores from the previous year to calculate the student’s progress toward meeting academic standards.

The most recent report available to view is the 2017 student growth report which includes individual student SGPs for all enrolled students in schools and districts across Wisconsin. These reports are designed to give educators and parents an overview of their students’ educational progress.

In the 2017 student growth report, educators can select from a list of prior and current school years to see their students’ projected SGPs for each content area for all four years of testing for each subject. This information is provided to help teachers plan their instruction to ensure that all students are on track to reach proficiency.

SGPs are calculated using a combination of the most recent test from a particular testing window and one or more tests from an earlier testing window. As a result, each year’s SGPs may be slightly different from the previous year.