Voting in the Bicameral Congress: Large Majorities as a Signal of Quality

We estimate a model of voting in Congress that allows for dispersed information about the quality of proposals in an equilibrium context. In equilibrium, the Senate only approves House bills that receive the support of a supermajority of members of the lower chamber. We estimate this endogenous supermajority rule to be about four-fifths on average across policy areas. Our results indicate that the value of information dispersed among legislators is significant, and that in equilibrium a large fraction of House members' (40-50%) votes following their private information. Finally, we show that the probability of a type I error in Congress (not passing a good bill) is on average about twice as high as the probability of a type II error (passing a low-quality bill).