Using longitudinal student data, statistical growth plots (SGPs) measure students’ relative progress compared to their academic peers. SGPs are the foundation of a student’s performance profile and provide teachers and administrators with a detailed picture of the student’s past and projected future achievement levels.
SGPs allow comparisons of student performance between assessment instruments and across years of testing. This is essential to ensuring that students’ growth across different assessments is accurately represented in their results, as different assessments have different test structures and specifications that can result in significantly different scale scores. SGPs also help to account for a variety of different starting points for students’ proficiency rates, as each assessment uses a different scale to measure student knowledge.
In order to create a valid and reliable growth score, the SGP methodology combines student’s previous MCAS test history with their current year’s test results to produce a percentile-based measurement of student growth. This provides educators and parents with a useful tool for determining how much growth a student needs to achieve their achievement target or maintain proficiency.
For example, a sixth grade student named Simon scored 370 on this year’s statewide exam in English language arts (ELA), a significant increase over her fifth-grade score of 300. SGPs display Simon’s score along with the scores of all other students in her grade with similar MCAS test histories. Simon’s percentile score of 90 shows that she is growing faster than 90% of her classmates with similar MCAS performance histories, indicating that her growth rate is very high.
The sgpData tables include many helpful tables, one of the most valuable being the sgpData_INSTRUCTOR_NUMBER table, an anonymized lookup table that allows districts to assign instructors to students through unique identifiers associated with their test records. This helps ensure that the proper instructor is assigned to a student’s growth calculations and allows for accurate and efficient SGP analyses.
SGPs are calculated for ELA and math in grades 4 through 8, as well as science at the high school level, for all students with valid test records from prior grade-level tests. SGPs are not available for grades 3 or 10 as MCAS tests do not have grade-level versions of these subjects in these grades. The sgpData tables include two options for viewing SGPs: Window Specific SGPs, which are generated when you select a prior or current window during the report customization; and Current SGP, which is an automatic calculation of a single SGP that is updated each time you run a Star Growth Report.
