The first U.S. charter school opened in 1992, and the scale of the charter movement has since grown to 4,000 schools and more than a million students in 40 states plus the District of Columbia. With this growth has also come a contentious debate about the effects of the schools on their own students and on students in nearby traditional public schools (TPSs). In recent years, research has begun to inform this debate, but many of the key outcomes have not been adequately examined, or have been examined in only a few states. Do the conflicting conclusions of different studies reflect real differences in effects driven by variation in charter laws and policies? Or do they reflect differences in research approaches--some of which may be biased? This book examines four primary research questions: (1) What are the characteristics of students transferring to charter schools? (2) What effect do charter schools have on test-score gains for students who transfer between TPSs and charter schools? (3) What is the effect of attending a charter high school on the probability of graduating and of entering college? (4) What effect does the introduction of charter schools have on test scores of students in nearby TPSs? (A bibliography is included. Data, Supporting Data and Regression Results are appended. Chapters and appendixes are individually footnoted. Contains 42 tables.) [For associated Research Brief, see ED504625.]