Searches identified 2,640 articles, with 49 ultimately included in the analysis (19 reviews and 30 original research articles). Articles published between 1988 and 2009 consistently advocated economic evaluation and increasingly provided methodological guidance. Twenty-one of the original research articles focused on child welfare, and 9 focused on child mental health. Of the 21 child welfare articles, 81 percent (17) focused on the United States system. Forty-seven percent (8 of 17) focused only on primary prevention; 83 percent of the peer-reviewed articles on the U.S. system focused exclusively on prevention (five of six articles) in the United States; however, 9 of the 17 articles included empirical follow-up (mean sample size of 264 individuals, and mean follow-up of 3.8 years). Ten of the 17 articles used modeling to project longer term outcomes, but 80 percent of the articles that used modeling were not peer-reviewed. Although 60 percent of modeling studies included interventions for children in the system, all peer-reviewed modeling articles focused on prevention. The authors conclude that methodological guidance for economic evaluations of child welfare systems is increasingly available; and such analyses are feasible, given the availability of nationally representative data on children involved with child welfare and evidence-based interventions. The literature reviews encompassed 19 repositories of peer-reviewed, and non-peer-reviewed "gray" literature, including items in English published before November 2009. Original research articles were included if they evaluated interventions based on costs and outcomes. Review articles were included in order to assess the relevance of these techniques over time and to highlight the increasing discussion of methods needed to undertake such research. Items were categorized by their focus on interventions for the United States child welfare systems, primary prevention of entry into the system, and the use of models to make long-term projections of costs and outcomes. 3 tables, 2 figures, and 83 references