The Statistical Analysis Of Roll-Call Data: A Cautionary Tale

Roll-call voting and congressional procedures are two of the most heavily studied aspects of the U.S. Congress. To date, little work has focused on the effect of procedures on the composition of the roll-call record. This article takes a step in this direction by demonstrating the effect of chamber rules and institutional constraints on House and Senate roll-call data, as well as on the inferences that scholars have drawn from the roll-call record. More specifically, I focus on recent efforts to measure party effects and ideological alignments, and I demonstrate that the composition of the roll-call record can affect these measures.