Public involvement in government decision-making is a basic aspect of modern democracy, and yet there has been very little empirical analysis of what contributes to successful citizen involvement. This project employs explicit criteria of success to analyze a large number of cases (more than 250) of public participation in environmental decisions. A number of different types of public involvement mechanisms are being studied, including public hearings, citizen advisory committees, mediations, surveys, focus groups, public education programs, and citizen panels. The results of the analysis are expected to provide better understanding of what factors contribute to successful participation and what mechanisms work best in particular circumstances.