The focus of this study is on the key events that individual children may experience in the public child welfare service system. The system includes both the government agency responsible for investigating and responding to child maltreatment and those private agencies that contract with the government agency to provide services. This report discusses the importance of this type of research, the issues that can be addressed with the information produced, an initial set of analyses addressing key questions in child welfare and an agenda for future work. This report is very much an introduction to the topic and only begins to address key questions around the careers of children across the entire child welfare system. It is in response to the conclusion of The Panel on Research on Child Abuse and Neglect that studies on this topic have the problems of lack of comparable data because of the variation of policies from state to state; a lack of explication of those policies; and the inability to disentangle aggregate data into its components which would allow making the results more comparable.