摘要:Regulatory agencies possess the particularity of being controlled by non-elected politicians whose power is derived from delegations made by incumbent powers. There exists, however, a concern with the creation of institutional mechanisms that permit public participation, thus guaranteeing greater democratization and social control of the regulatory process. One of these participatory mechanisms is the public hearing, which was not given much attention by Brazilian literature on lobbying and interest groups. This article seeks to contribute to fill this gap, focusing on the impact of interest groups acting upon the National Civil Aviation Agency, ANAC. Analyzing comments sent to the public hearings, we identified the commentators and the intensity of their participation, the impact of their efforts as measured by the rate of comment incorporation, and we explained why some comments are incorporated and others are not. We organized an original data base of the comments made at all ANAC public hearings between 2007 and May 2012. We analyzed 518 comments concerning 48 regulations. To test participant influence, we classified the comments by degree of technicality, economic or legal argument, authorship, and request for regulation. To understand the incorporation process, we used regression models through which we presented evidence that a comment’s incorporation is directly related to its degree of technicality. Technical comments, which effectively subsidize the resolution, have a higher chance of being incorporated. Even more than corporate power or its force of participation, the technical quality proved to be the main factor for comment incorporation.