Student Growth Percentiles (SGP)

When students take exams, their performance is measured against that of students with similar prior score histories. Their percentile rank reveals how well they performed relative to those who scored lower; the higher it is, the better their results are.

Student Growth Percentiles (SGPs) measure how a student has progressed academically over time. Calculated by comparing test scores among similar academic histories – usually their previous year’s test score – SGPs assign students between 1 and 99 as percentile rankings within this group; higher ranks indicate better academic achievements while lower ones suggest worse performances among similar educational histories.

SGPs give educators the information they need to enhance instruction and assess the efficacy of their programs, including educator evaluations, teacher plans for improvement and setting school/district goals. Furthermore, SGPs can also be utilized when evaluating accelerated programs with smaller but still significant numbers of students who struggle to keep pace.

DESE offers Student Growth Profiles in ELA and Math for grades 4 through 8, as well as in science for grade 10. SGPs for grades 4-5 compare prior assessment score histories to tests taken recently in those grades; while for grade 10 SGPs compare 10th grade test scores against 8th grade scores without including previous year’s Badger tests scores.

Districts must first collect and store their data before initiating operational SGP analyses, using an example data set like sgpData as an example of this practice. It contains five years’ worth of student assessment information in WIDE format arranged alphabetically with columns ID as unique student identifiers followed by five columns for scores for 2013, 2014, 2015, 2016 and 2017 tests taken across five years (SS_2013 to SS_2017).

The prepareSGP function offers an efficient means of transforming sgpData into a format compatible with SGP analyses. It accepts two lookup files of data (sgpData_LONG and sgpData_INSTRUCTOR_NUMBER) and produces one Demonstration_SGP@Data object that contains both types.

The analyzeSGP function performs actual SGP analyses. It uses a sgpData@Data record to create student growth percentiles, lagged projections and baseline projections. CombineSGP merges results derived from this analysis into the sgpData record and generates scale scores associated with SGP targets, while also merging all outputs from this and prior SGP analyses into one longitudinal record. Producing an SGPData@Data file that can be accessed by students, educators and administrators for informed instructional decisions is crucial in ensuring SGPs are accurate, meaningful and actionable – without careful preparation errors in SGP analyses can quickly revert back into problems in the data.