Does Bill Co-sponsorship Affect Campaign Contributions?: Evidence from the U.S. House of Representatives, 2000-2008

There is considerable variation across members of the United States House of Representatives with respect to the number of bills they co-sponsor each legislative cycle. But we have little understanding of what motivates bill co-sponsorship activity. It seems unlikely that prospective campaign contributors to a specific legislator reward his/her bill co-sponsorship activity per se, as it merely contributes to the productivity of some other member(s) of the legislature. We develop a two-stage least squares (2SLS) model to examine the impact of the number of bills co-sponsored by members of the U.S. House of Representatives on campaign contributions received by those individuals over the time period 2000-2008. Bill co-sponsorship has a large and positive effect on campaign contributions through bill sponsorship.