Joshua D. Angrist, Sarah R. Cohodes, Susan M. Dynarski, Parag A. Pathak, Christopher D. Walters
Boston’s over-subscribed charter schools generate impressive gains on tests taken through the Massachusetts Comprehensive Assessment System (MCAS). Lottery estimates show that each year spent at a charter middle school boosts MCAS scores by about a fifth of a standard deviation in English Language Arts (ELA) and more than a third of a standard deviation in math. High school gains are just as large (Abdulkadiroğlu et al., 2011). These results are in line with those generated by urban charters elsewhere in Massachusetts, as we’ve shown in studies of a Knowledge is Power Program (KIPP) school in Lynn, Massachusetts (Angrist et al., 2010, 2012), and in an analysis of achievement effects in charter schools from around the state (Angrist et al., 2011a,b).
Our new findings suggest that the achievement gains generated by Boston’s high-performing charter high schools are remarkably persistent. While the students who were randomly offered a seat at these high schools graduate at about the same rate as those not offered a seat, lottery estimates show that charter enrollment produces gains on Advanced Placement (AP) tests and the SAT. Charter attendance roughly doubles the likelihood that a student sits for an AP exam and increases the share of students who pass AP Calculus. Charter attendance does not increase the likelihood of taking the SAT, but it does boost scores, especially in math. Charter school attendance also increases the pass rate on the exam required for high school graduation in Massachusetts, with especially large effects on the likelihood of qualifying for a state-sponsored college scholarship. Other estimates suggest that charter attendance may increase college enrollment, but the number of charter applicants old enough to be in college is still too small for this result to be conclusive. By contrast, our results show that charter attendance induces a clear shift from two-year to four-year colleges, with gains most pronounced at four-year public institutions in Massachusetts.
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