New forms of governing and managing public schools have proliferated in recent years, spawning the establishment and growth of companies that operate public schools under contract. Among these education management organizations, or EMOs, the largest and most visible is Edison Schools, Inc., with a nationwide network in 2004?2005 of 103 managed schools, including preexisting schools contracted to Edison by districts and charter schools that Edison played a role in starting up. In 2004?2005, Edison served approximately 65,000 students in the schools it managed and tens of thousands of additional students through other initiatives. The entry of EMOs, many of which operate as for-profit companies, into the public education system has generated fierce debate, and Edison has been the focus of much of that debate. To date, however, there has been little empirical evidence regarding EMOs? effects on schools and students. In 2000, Edison asked the RAND Corporation to conduct a comprehensive analysis of its achievement outcomes and its design implementation. RAND designed an evaluation to address the following research questions: ? What are Edison?s strategies for promoting student achievement in the schools it manages? ? How are Edison?s strategies implemented in the schools it manages? ? How does Edison?s management of schools affect student achievement? ? What factors explain differences in achievement trends among Edison schools?