The data sgp package leverages longitudinal student assessment data to produce statistical growth plots (SGPs). SGPs measure students’ progress relative to the performance of their academic peers. These growth plots are useful for understanding students’ achievement level trends, identifying student groups that require additional support, and for assessing the effectiveness of programs.
Educators and administrators use SGPs in conjunction with educators’ SLO process and to guide district-wide improvement efforts. Individual students’ SGPs can be shared with parents to help them understand their child’s learning journey. These growth patterns can also be compared among schools and districts using aggregated SGP information to assess differences in student outcomes across the state.
SGP analyses are complex. They require the right software/hardware, data preparation and an understanding of the SGP methodology. The bulk of the time spent on running SGP calculations is on data preparation. This includes defining the right metric for each content area, creating and importing the appropriate data sets, creating the necessary indexes, and reworking or creating new variables. These steps are critical to the accuracy of the SGP analyses. Often, errors found in the data that cannot be explained by other factors will be caused by incorrectly prepared or processed data.
To avoid these errors, it is important to take the time to properly prepare data for SGP analyses. There are many resources available to assist with this task. We suggest that you read through the SGP documentation, vignettes and examples prior to conducting any analyses.
While the sgpData_LONG format is used by lower level functions such as studentGrowthPercentiles and studentGrowthProjections, higher level wrapper functions such as abcSGP and updateSGP utilize the sgptData_LONG data set with several preparation and storage benefits over WIDE formatted data. In addition, the sgptData_INSTRUCTOR_NUMBER lookup table provides instructor detail associated with each student test record which is used to calculate a students’ teacher-level SGP.
Typical SGP scores for individual students range from about 36 to 64. A score below the 36th percentile means that a student is making less progress than 75% of their academic peers on the same assessment. Similarly, a score above the 64th percentile indicates that a student is making more progress than the average student on their assessment.
Students who achieve high SGP scores need to be able to translate those gains into educationally meaningful targets for their future performance levels. SGP helps teachers and students articulate these targets by showing them the magnitude of the required improvement. This clarity will be helpful for accelerating programs that risk being held back by a small percentage of students who do not keep pace with their peers. This can be especially challenging for students with special needs, whose challenges may make it more difficult to meet their target goals. Using SGP allows these students to be identified and targeted for assistance. This will help these students and their teachers to reach their potential. In turn, these gains will contribute to the overall achievement of the state’s students.
