This article presents the main results and the main conclusions of an applied research that aimed to answer the following question: within the Federal Executive Branch, what are the main factors that impact the potential of effectiveness of public hearings as a mechanism of social participation in the management process of public policy?. For this purpose, and through the use of qualitative methodology, the research relied on four case studies of hearings held by Federal Government agencies: the preparation of the National Solid Waste Management Plan; the debate on the drafts of the bidding terms and conditions, and regarding the contract of permission to exploit Interstate Bus Services; and the environmental licensing of two major hydroelectric projects - Santo Antônio/Jirau, in the state Rondônia and Belo Monte, in the state of Pará. The results of the empirical analysis point out factors that influence the effectiveness of the hearings. This analysis aimed to provide subsidies for public managers responsible for organizing and conducting these participatory processes, as well as for scholars concerned with the issue.