A paper by two researchers at the Massachusetts Institute of Technology examines the consequences that follow from an expansion in the number of charter school places available for enrollment. The study uses data from Massachusetts, where charter school growth has been carefully managed and where there was significant excess demand for charter school places. In 2011, the state increased the cap on charter school enrollments in districts with low test scores, resulting in a large increase in charter school enrollment in some of these districts. The paper analyzes three outcomes: (a) changes across charter and non-charter public schools in funding (how much resource was available per student), (b) resource allocation (how schools spent their funds), and (c) achievement (how well students performed on academic tests).