Data SGP utilizes longitudinal student assessment data to produce statistical growth plots (SGPs), which enable us to track each student’s relative progress relative to academic peers. These SGPs can be used to ascertain whether a school is making sufficient progress towards meeting an agreed-upon growth target (e.g. 75% of their academic peers). SGPs are founded on the notion that student progress is directly proportional to how quickly they meet an achievement standard. Compare students’ Standardized Test Score Growth across multiple assessments and years may result in inaccurate correlations, creating SGPs from students’ test score histories requires complex calculations that may introduce errors into the process.
SGP data not only has educational value; it is also an indispensable resource in shaping local and state policy decisions. SGPs can identify areas that require additional resources, ensuring all students receive high-quality education; they can highlight improvements needed across specific subjects or grades within schools/districts; they can even be shared with parents for a clear picture of how their child performs in class.
The sgpData_LONG data set contains all of the data required to run SGP analyses and provides teachers with various tables that facilitate their use of results. One particularly helpful table is sgpData_INSTRUCTOR_NUMBER; an anonymized lookup table which displays instructors associated with all assessments records tested during an academic year for all content areas tested; this allows teachers to quickly identify which instructors teach students who share similar grade level and demographic groupings.
Figure 1 highlights one key advantage of using SGPs over medians as an aggregate measure: they do not mask differences among schools. As seen here, school SGP distributions tend to be much tighter when using means rather than medians; this may be caused by various factors including teacher or school characteristics as well as design of baseline cohorts for student achievement.
SGPs are calculated based on student performance on one or more MCAS tests from different testing windows, and display as percentiles; higher numbers represent greater relative growth; for instance, an SGP with the 90th percentile would indicate that their MCAS score exceeds 90% of other students with similar test history.