This document summarizes research on school reform strategies aimed at increasing graduation rates and student performance among low-income students. It describes how New York City closed underperforming large high schools and replaced them with new small schools and charters designed around principles of effective schools. These reforms led to dramatic improvements, with graduation rates rising from 35% to over 75% on average. Examples of high-performing charter networks, such as Green Dot and North Star Academies, showed how school designs emphasizing accountability, high expectations, and extended learning time can help close achievement gaps.