Inducing Polarization? The Effect of Congressional Procedure and Partisan Lawmaking on Ideal Point Estimation

How do procedural innovations, such as committee bypass, affect our roll-call-based measurements of individual member ideology — and therefore our measurements of polarization? Congressional polarization, 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 effect of one unorthodox procedure — the use of committee bypass in the House — on the measurement of member ideology and chamber polarization. We utilize matching to generate balanced subsets containing similar bills that bypassed committee to reach the floor and bills that went through “regular order.†With these matched subsets, we estimate the effect of committee bypass on roll call votes and the resulting ideal points and polarization measures. We find that committee bypass has the effect of dampening, rather than exacerbating polarization.