Over the past 30 years, the charter school movement has become a significant factor in U.S. public education. Charter schools were originally designed to be alternative public schools that would allow for greater experimentation and innovation within the public school system. As the number of charter schools has expanded to more than 7,000 nationwide, an active debate has arisen focused on the ways in which charter schools either help or harm the public school system and what should be the appropriate regulation of charter school certification, operation, and expansion. In this issue's Point/Counterpoint, we consider the evidence on charter schools, addressing three critical questions: (1) To what extent do charter schools promote, or interfere with, the public interest in K-12 education that justifies its public funding?; (2) Do charter schools help to equalize educational opportunity?; and (3) Should policymakers at a state or district level limit the size of the charter school sector? Philip Gleason, Senior Fellow at Mathematica, reviews the evidence on charter school effectiveness and asserts that charter schools have stimulated critical experimentation and learning around how to serve schoolchildren more effectively, and he argues that continuing the charter school movement would expand our learning. Helen Ladd, Professor Emerita of Public Policy and Economics at Duke University, also considers the evidence on charter school effectiveness but more closely focuses on the degree to which charter schools interfere with the operation and coherence of local school systems. Professor Ladd argues that given the operational and financial burden that charter schools create for public school systems, we should cap the number of charter schools and refocus attention and resources on traditional public schools.