The data sgp package provides an interface to run student growth percentile (SGP) analyses for the Star examinations. The software/hardware requirements for running SGP analyses are fairly straightforward and the data preparation process is relatively simple.
SGPs produce a percentile ranking of scale score changes for students with a common starting point. For example, if a student’s SGP in 2023 is 63, it means that the student grew as much as or more than 63 percent of their academic peers who also started at the same place. However, it’s important to remember that SGPs are calculated anew each year. This means that differences in SGPs from one year to another must be interpreted with caution.
As a general rule, a student with an SGP in the 50th percentile or above is doing well and growing at a pace that places them close to proficiency. Students with SGPs in the 40th percentile or below are still growing, but not as fast as their peers.
It’s important to note that SGPs only measure the growth of individual students – they do not give a snapshot of the growth of an entire group or district. For this reason, comparing SGPs between different groups or districts is not a valid comparison.
The sgpdata package contains 4 examplar data sets that can be used to conduct SGP analyses. The first data set, sgpData_WIDE, specifies data in the WIDE format that’s used by lower level SGP functions like abcSGP and prepareSGP. The second and third data sets, sgpData_LONG and sgptData_LONG, specify data in the LONG format used by higher level SGP functions like studentGrowthPercentiles and studentGrowthProjections.
sgpData_INSTRUCTOR_NUMBER specifies a teacher-student lookup table that’s utilized by the analyzeSGP function to produce teacher level aggregates. The fourth data set, sgpData_ALLDATA, includes all of the WIDE and LONG formatted SGPdata in a single file that can be downloaded and opened with any text editor.
The SGPdata website also includes a variety of documentation on using SGPdata including detailed tutorials on how to use the prepareSGP and studentGrowthPercentiles functions. The SGPdata website is available for anyone to access at no cost. The site also offers a subscription service for access to additional tools and services that are more sophisticated than those available through the free website. The subscription services include the ability to download, process and store large datasets, create customized visualizations of SGP data and access to a number of advanced statistical analysis tools. The subscriber based services also offer the ability to customize SGP calculations and to access other state assessment data including cut scores, CSEMs, and teacher growth percentiles. The subscriber based services are billed on a per-student basis and can be purchased through the SGPdata website. The subscription service prices range from $5 to $15 per student. The subscription service is not required to use SGPdata and it can be disabled at any time.