A “roll” occurs when a majority of a subset of the legislature (e.g., a party caucus) unsuccessfully opposes a particular bill’s passage. Rohde (2005b) tallies the yeas and nays for members of each party on roll call votes. Final passage roll rates are based on Rohde’s Vote Types: 11, 12, 15, and 30. Amendment roll rates are based on the vote types: 21 through 29.

To calculate committee of jurisdiction roll rates, we obtained individual voting positions on each roll call from Poole’s VOTEVIEW and then merged them with committee membership information (Stewart and Woon n.d.) so that we were able to calculate the proportion of voting committee members taking yea and nay positions on each roll call.

Next we use committee of jurisdiction information drawn from the Congressional Bills Project to identify which of these committees was the committee of jurisdiction for the bill that was the focus of each roll call. A committee was rolled if the majority position of the committee members was different than the majority position of the legislature.

The central limitation of this approach is that some of the bills considered on the floor (about 15%) are multiple referrals. We thus identify a committee roll for multiple referrals when most of the committees of jurisdiction are rolled in cases of multiple referrals. Restricting the focus of this analysis to singly referred bills only does not substantively alter its conclusions.