Data SGP is a longitudinal student assessment analysis tool that generates statistical growth plots (SGP), providing visual evidence of students progress relative to their academic peers. SGPs are calculated by combining students standardized test score with covariate information such as prior testing history to create an “growth standard”, providing an objective measure of student performance.
SGPs differ from many other assessment metrics in that they are reported as percentiles instead of specific scaled numbers, making them easy to comprehend by both students and educators alike. Therefore, SGPs can easily be utilized for classroom instructional practice, research initiatives, school/district evaluation, as well as communicating to their students how much growth must occur to reach an achievement target/goal in an agreed upon timeframe.
SGPs not only give educators a visual representation of student performance, they can also help identify which students may require additional assistance or additional support to catch up. SGPs can also be invaluable tools for showing the success of an accelerated program by showing which percentage of their students were on track to reach an achievement goal within an allotted timeframe without being held back by those not yet successful in doing so.
To conduct SGP analyses, the first step involves collecting and examining data. After this has been completed, running SGP calculations – designed to be as straightforward and user-friendly as possible – is usually required; usually more time will be needed preparing and analyzing than running calculations for SGP analyses.
Preparing and analyzing SGP data requires several key considerations, such as data format, availability, software/hardware compatibility and the complexity of running calculations. It is also vital that data transformations are applied appropriately so that final outputs make sense.
Once SGP calculations have been conducted, the next step should be presenting and sharing results in various formats – graphs, charts or timelines are just a few options available – in order to showcase and communicate them to stakeholders. When sharing results it is vitally important that graphs and charts are formatted properly so they are easy to read and comprehend.
The SGPdata package contains an example WIDE format data set (sgpData) to simulate time dependent data required by studentGrowthPercentiles and studentGrowthProjections at lower levels. sgpData includes five years of vertically scaled anonymized vertical growth data from 2011 – 2014. The data set contains unique student identifiers for every year in which grade level assessments took place, followed by columns containing assessment scores for those years. SGPdata includes a LONG format data set to aid with the transformation of wide data into long data that can be utilized by higher level functions. To maximize operational SGP analyses, LONG format is recommended since this offers numerous preparation and storage advantages over WIDE data formats.