This paper explores the extent and character of interest group influence on legislative policy in a model of decision making under incomplete information. A committee may propose an alternative to a given status quo under closed rule. Policies are related to consequences with ex ante uncertainty. An interest group is able to acquire policy—relevant information at a price, and has access to legislators at both the agenda setting stage and the vote stage. Lobbying is modeled as a game of strategic information transmission. The price of information is itself a private datum to the group, and legislators cannot observe whether the group elects to become informed. If the group is informed, then its information is likewise private. Among the results are: that not all informed lobbyists choose to try and influence the agenda directly; that there can coexist influential lobbying at both stages of the process; and that while informative agenda stage lobbying is genetically influential, the same is not true of voting stage lobbying.