A student’s growth percentile (SGP) indicates how much a student has grown relative to students with academically-similar prior test scores (their academic peers). This is often the best measure of a student’s achievement progress, particularly for educators, because it provides a clear and consistent way to describe a student’s performance. SGPs are measured on a scale of 1 to 99, with lower numbers indicating lower relative growth and higher numbers indicating greater relative growth.
To learn more about the underlying calculations used to calculate SGPs, visit our SGP FAQ page.
The data sgp tool is intended to make it easy for educators to analyze and interpret the student growth information available in the data set. This tool is built upon the R statistical software environment; it is open source and free to use. The tool can be run from the command line or as a Python script; either option allows you to quickly get up and running with SGP analysis.
Using the tool requires the user to have a computer with Windows, OSX or Linux and access to the free software download of the R statistical programming environment. While the tool is designed specifically to work with educational assessment data, the tools can be used for other kinds of statistical data analysis.
While the term “big data” has become a common phrase in many fields, the amount of data analyzed by data sgp is actually fairly small when compared to, for example, analyses of global Facebook interactions. Consequently, the bulk of the time spent using the tool is in data preparation and analysis.
To get started with SGP analyses, the user must create an sgpData file. This file includes a list of test records for each student and provides the identifiers and dates associated with those records. The data sgp tool then uses the sgpData file to produce an individual level summary of the students’ SGP.
A summary of the SGP data for each student is displayed in a table. The table contains two columns, one for the sgpPercentile and one for the sgpGrowthIndex. Each column contains a number between 1 and 100, with lower numbers indicating a lower relative SGP and higher numbers indicating a greater relative SGP.
The tool also produces two other types of tables that are useful for analyzing and reporting SGP information. These are Window Specific SGP, which is useful for comparing students’ SGP over time frames, and Current SGP, which is useful for providing the most recent SGP available for a student as a quick check-in on progress. The sgpData tool also provides options for formatting the results of the table and additional functions for SGP analysis. The sgpData_LONG vignette provides more detailed documentation on how to use the LONG format for SGP analyses.