Data SGP (Data on Student Growth and Progress) is a collection of aggregated measures that provide educators and parents with the opportunity to see how their students are progressing over time. The data includes individual-level results like test scores and growth percentiles as well as broader aggregated student and school level information such as class size, gender, ethnicity and socioeconomic status that are used to inform classroom practices, shape research initiatives and support larger educational efforts.
In order to calculate SGP, DESE identifies the most recent assessment from each content area (ELA and Math) as the current assessment. It then compares that assessment with a prior assessment (from the same testing window) to determine the current SGP. This process is repeated for all students who have valid test records in at least one testing window.
The SGP that is reported for a student represents the relative difference between his or her current MCAS score and the average score of students who have a similar MCAS performance history. The most common interpretation of SGP is that a student who grew at the 90th percentile grew faster than 90% of the students who performed similarly to him or her in the past.
A key advantage of SGPs is that they are calculated relative to the achievement of students with similar prior achievement, which makes them potentially more fair than other performance measures that are correlated with student background variables. However, while SGPs can be helpful in understanding student learning and performance, they are not a complete measure of achievement. Ideally, future improvements in tests and SGP estimation methods would remove undesirable correlations between SGP and student background variables, further increasing their fairness.
SGPs are not a perfect measure of progress; they can be influenced by several factors including the pace of instruction, teacher preparation and student motivation. In addition, they can be distorted by the relatively few students who are not able to keep up with the rest of the class, especially if that small group represents an entire grade level or cohort of students. To mitigate these limitations, we have developed a set of tools and analyses to help educators understand the strengths and weaknesses of SGP measures.
The sgptData_LONG data set provides a variety of anonymized tables with long format data for the years 2013, 2014, 2015, 2016 and 2017. These include the sgpData_INSTRUCTOR_NUMBER table an anonymized lookup table providing instructor details associated with each student test record and the sgpData_STUDENTS_PERCENTILE_TABLE that allows teachers to view expected growth percentiles at a classroom or district level for the most current academic year. To use these data sets, you will need a computer with the R software installed. You can find information on getting started with R by viewing the sgptData_LONG vignette or the sgp Data Analysis vignette. These vignettes provide detailed instructions on how to prepare and run SGP analyses. The sgpData_LONG vignette also discusses the characteristics of the data and provides additional documentation on the underlying methodology for calculating SGPs.