Comparing Floor-Dominated and Party-Dominated Explanations of Policy Change in the House of Representatives

We test two explanations of the legislative process for their ability to account for the ideological pattern of policy change produced by bills enacted by the House of Representatives, 1953-1996. The Floor-Dominated explanation argues that the floor's median member largely determines legislative outcomes, while the Party-Dominated explanation claims that power for the majority party. We develop three measures of the ideological pattern of policy change and independent variables that reflect the predictions of the two explanations. While we find support for both explanations, the greater significance, both substantively and statistically, of the Party-Dominated explanation leads us to conclude that the House's agenda-setting process is largely controlled by the majority party.