Data sgp is a tool that allows teachers, students and families to view growth information in percentile terms that are more intuitive for many users. Unlike value-added models that use complex mathematical calculations to assign teacher level scores, SGPs present growth information in the context of rank ordering students of similar baseline academic performance. The interpretability of SGPs makes them more useful for policymakers and practitioners than other more statistically complex measures of educator effectiveness such as a student-level average or standard deviation.
To provide clarity in the interpretation of SGPs, DPI has created a set of SGP data explorers to allow users to select a specific window or date range of interest. The following explorers are currently available:
sgptData_LONG
The data set sgptData_LONG contains anonymized LONG format assessment data in three content areas (Early Literacy, Mathematics, and Reading) for 8 windows (3 windows annually). This dataset is required if running student-level growth analysis using the summarizeSGP function. In addition, this data set is used to create the student aggregates and achievement plots provided in the Summary of SGP Analysis Report.
sgpData_INSTRUCTOR_NUMBER
The sgpData_INSTRUCTOR_NUMBER data set provides in-depth data on the association between student assessments and their individual instructors. This data can be used to generate individual growth percentile analyses for students and groups of students based on the instructor they had each year, as well as create aggregated teacher growth reports.
SGPs are a useful way to measure student progress, and they can help identify students who may be at risk of failing to meet state proficiency standards. However, in order for SGPs to be meaningful, they must be interpreted properly and the growth of individual students must be reported in relation to their peers. To do this, SGPs are calculated by comparing a student’s growth percentile with the growth of their peer group in each subject area and grade level.
To improve the interpretability of SGPs, DPI has incorporated several methods to normalize the scale score distribution. This normalization is accomplished by removing the highest and lowest scores from each scale score range, then dividing by the total number of scores to create an index that represents the center point of the scale score distribution. A set of knots and boundaries is then chosen to define the bounds of this distribution, which are used in all subsequent analyses to ensure that all students are being compared against a common standard. The resulting distributions are then used to calculate the average, median and student-level SGPs. The charts and tables produced from these analyses are meant to give users a clearer understanding of how SGPs are computed and what they mean for individual students and the teachers who teach them. The normalized distributions also serve to mask the effects of a single year’s unusually high or low results, as would be seen in a typical stacked bar chart. This helps to reduce the impact of one-year anomalies on SGPs and enables more meaningful comparisons between teachers and across schools over time.