The Limits of Lobbying: Null Effects from Four Field Experiments in Two State Legislatures

It is widely thought that lobbyists exert influence over legislators' policy positions and, as a result, over policy outcomes. One mechanism of influence is the provision of policy expertise. Yet, there is little credible empirical evidence that lobbyists' expertise influences legislative outcomes. Across four experiments fielded with three lobbyists in two state legislatures that examine two public measures of legislators' positions, we find no evidence that lobbyists' expertise influences legislators' policy positions. We do find, in contrast, that the same policy expertise treatment is influential when provided by a legislative staffer. We conclude that policy information can influence legislators' positions, but that legislators are cautious when that information is provided by lobbyists.