Data sgp is an R software package created to make SGP analyses simpler for its users. As such, it requires knowledge of both its program and R programming language (freely available on Windows, OSX and Linux) for use. Most time spent in SGP calculations is actually devoted to data preparation rather than analysis itself; once everything is in order for most analyses they simply import their data into an SGP database before initiating their calculations.
Student Growth Percentiles, or SGPs, measure students’ progress on an MCAS content area test by ranking them relative to those who started out with similar academic performance. SGPs are seen as more interpretable than value added models (VAMs) because they rank students on how much their growth compares with that of their peers and use growth percentile terms that can easily be understood by educators, parents and community members.
SGPs can be more versatile than other statistical measures like mean or median scores in that they provide more data about how each student compares with his/her peers and may therefore prove more helpful for teachers and administrators when it comes to identifying areas of strength as well as those that require improvement.
The SGP package comprises lower level functions for performing studentGrowthPercentiles and studentGrowthProjections calculations as well as higher-level wrapper functions that enable users to produce reports at school, district or subgroup levels. While lower-level SGP functions require WIDE formatted data for calculations, higher level wrapper functions that include state specific meta-data embedded into sgpData work with LONG formatted data sets for operational analyses year after year – thus making long data sets much easier than their wider counterparts! We highly advise users of SGP data prepare their data in LONG format when planning operational analyses on year after year operations as handling long data sets is much simpler than working with wide data sets!
Note that SGPs are only as reliable and meaningful as the data used to calculate them, which is why high quality data must be used for calculations in order to produce accurate and meaningful SGP results. Therefore, in order to achieve meaningful SGP calculations it is vital that data used be of top notch quality; to this end the SGP project has developed guidelines to help ensure high quality results are produced – these can be found at SGP Data Guidelines page.