Competitive lobbying for a legislator's vote

This paper develops a model of interest group lobbying based on the central premise that such lobbying is fundamentally an exercise in strategic information transmission. Lobbyists typically possess information that legislators do not and, inter alia, such information is relevant to legislators when it concerns the consequences - either policy or political - of supporting one bill rather than another. However, given that the interests of lobbyists do not necessarily coincide with those of legislators, the extent to which a lobbyist is able to persuade a legislator to act in his or her interest is moot. The paper explores the extent to which lobbyists can influence a legislative decision in such a setting; in particular, we are concerned with the incentives for interest groups to acquire costly information and lobby a legislator when there exist other groups that do not share the same interests. Among the results are that a legislator will on average make "better" decisions with lobbying than without, and that the more important is an issue to a special interest group, the more likely is the legislator to make the correct full-information decision.