Politics to the Extreme: Mapping the Interest Group Universe

Abstract

This research aims to accomplish two things: 1) to calculate the policy ideal points ofinterest groups, and 2) explore whether polarization in the Congress is reflected in the interestgroup universe. I utilize congressional roll call vote data coupled with a mathematical algorithmto map shifting ideological “ideal points” of interest groups over time in one and twodimensionalspace. I observe potentially meaningful similarity between movements of legislatorand interest group ideal points, wherein interests groups are treated as voting members of theUS House.