Data SGP is an analysis tool that assembles longitudinal student assessment data to generate statistical growth plots (SGPs). SGPs show students’ academic progress over time in comparison to their peers. This data is a valuable tool for districts to track individual student academic progress, identify students at risk of not meeting achievement goals, and support accelerated programs.
SGPs use standardised test scores and covariate information to compare a student’s performance to that of their academic peers. The SGP calculation is more accurate than a traditional percentile score because it takes into account the student’s previous testing history. A higher SGP means that the student’s current performance is closer to those of their academic peers than it was in a prior year, and it also means they have demonstrated greater achievement growth.
Students’ SGPs are calculated for two content areas: reading and math. The SGPs are then weighted to determine the overall SGP rating score for each student. The overall SGP rating score is then divided by the number of years the student has tested to create the yearly average SGP. The yearly average SGP is then multiplied by the student’s age to obtain their growth percentage (G%).
There are two common formats for representing longitudinal (time dependent) student assessment data: WIDE and LONG format. The sgpData data set installed with the SGP package contains exemplar WIDE and LONG format datasets to assist with setting up a database for SGP analysis. In the sgpData table above, ID represents each unique student identifier. The first 5 columns, GRADE_2013, GRADE_2014, GRADE_2015, GRADE_2016, and GRADE_2017, represent the grade level of each student’s assessment score in the respective year. The final five columns, SS_2013, SS_2014, SS_2015, SS_2016, and SS_2017, provide the scale scores associated with each student in each of the respective years.
The SGPs displayed in the sgpData table are calculated by using up to 5 years of student assessment data, including their Badger year performance. The SGPs are then compared to other students’ SGPs to calculate each students’ relative growth percentile. A SGP of 85 indicates that a student has demonstrated greater growth than 85% of academically similar students.
The SGPs presented in the sgpData table are not indicative of a typical distribution for any given school. This is due to the fact that SGPs are calculated for each individual student, and not a group of students with a common assessment score or grade level. For this reason, the sgpData table is provided as an example only and should not be used to make conclusions about how a specific district’s SGPs will look. For more detailed explanation on how SGPs are computed, please refer to the SGP Data Analysis Vignette. If you have any questions about the data sgp table or SGPs, please do not hesitate to reach out. We are happy to help! The more we understand how you are using the SGP tools, the better we can build new ones for you.