Using Student Data to Create Statistical Growth Plots (SGPs)

The sgp package leverages longitudinal student assessment data to produce statistical growth plots (SGP). SGPs measure students’ relative progress compared to their academic peers based on an achievement target/goal established using prior test scores and covariates. However, creating SGPs from standardized test score history results in complex calculations that lead to large estimation errors, making these plots virtually unusable for measurement purposes. The SGP package solves this issue by providing a set of user-friendly functions that create high-quality SGPs for individual students and schools/districts.

SGPs are a powerful tool for communicating how well a student is performing and can help educators identify students in need of additional support to meet their achievement targets/goals. SGPs also allow educators to better articulate and measure the impact of accelerated programs on student progress. However, they should not be viewed as a replacement for official achievement targets/goals as students who may have different learning styles or needs require unique supports.

Educators can view the SGP for a student by selecting a student in the report and choosing the “SGP Data” tab. The resulting spreadsheet contains a row for each assessment occurrence for the selected student. The first column, ID, provides the unique student identifier. The next five columns, SS_2013, SS_2014, SS_2015, SS_2016 and SS_2017, provide the scale scores associated with each of the student’s assessment occurrences. The first value in each cell represents the student’s SGP percentile indicating whether the student has grown more than, less than or about as much as their academic peers.

Another important feature of the SGP package is its ability to generate a SGP for any group of students by selecting a school or district and then a year. This functionality is particularly useful when comparing the performance of students in similar content areas or grades, i.e., when evaluating a cohort of students or a class of teachers.

Lastly, the SGP package provides an option for users to export the SGPs they have generated. This functionality is especially helpful for those who would like to use their SGPs for additional analysis, such as comparing students across schools or districts, analyzing teacher performance, and/or supporting broader research initiatives.

The sgpData dataset is an anonymized, panel data set comprised of 5 years of annual, vertically scaled assessment data. It is an exemplar dataset that models the format of data that can be used with the lower level studentGrowthPercentiles and studentGrowthProjections functions in the SGP package. The sgpData dataset includes an additional column, sgpData_INSTRUCTOR_NUMBER, which provides instructors for each of the students in the data set. Please consult the sgpData Analysis Vignette for more comprehensive documentation on how to use this dataset and WIDE data formats in general for SGP analyses.