The Atlanta Journal-Constitution, after releasing its "Cheating Our Children" series that identified suspicious test scores around the country, provided the NICAR Database Library with test scores data gathered from state education departments.
From the AJC: "The data include state testing data paired in approximate cohorts by school, test subject and grade. An approximate cohort would pair, for example, average third-grade math scores at a school in year 1 with fourth-grade math scores at that school in year 2."
The data are currently available for free to all IRE members and can be downloaded from the Database Library website at https://www.ire.org/nicar/database-library/databases/school-test-score-data/.
Looks like you haven't made a choice yet.