States play an important role in serving children with a need for mental health services. In order to improve the mental health care system for this vulnerable population, it is necessary to better understand the need for mental health services, their availability, and their effectiveness across states. This report reviews the recent literature on childrens mental health services and examines a wide range of data sources for state-based analysis. It considers the feasibility of producing a comprehensive evaluation of state mental health systems for children and discusses the potential limitations of such an analysis.