Inducing Polarization: Procedural Bias in Ideal Point Estimation

• In Event: Ideology in Times of Polarization

Abstract

Congressional polarization, as measured using member ideal points derived from scaling roll call data, has been steadily increasing over the last half-century. However, changes in legislative procedure that affect the construction of the roll call record have been concurrent with this apparent increase in polarization. In this paper, we explore the implications of one particular procedural change—the increasing use of committee bypass in the House—on the measurement of member ideology and chamber polarization.

We argue that committee bypass creates an information asymmetry between majority party leaders and rank-and-file legislators regarding the contents of legislation. This informationally-constrained environment facilitates party-line voting on the floor, as members become reliant on their party leaders for cues about how to vote. This artificial inducement of party-line votes drives observed separation between the parties without changing members' underlying ideal points, altering the data generating process for roll calls.

This paper approaches this question as a three-stage problem. First, we estimate the observed effect of committee bypass on roll calls broadly, comparing party-line votes on bypassed and non-bypassed legislation. Secondly, to estimate the effect of committee bypass on roll call votes, we utilize matching as a form of pre-processing to generate balanced subsets –containing similar bills that bypassed committee to reach the floor and bills that went through “regular order.” Finally, we use these sets of counterfactual bill states to estimate two different sets of ideal points and compare the relative effect that additional bypassed legislation on estimates of chamber polarization.

Authors

• Austin Bussing, Sam Houston State University

• Joshua Yoshio Lerner, NORC at the University of Chicago