Party Pressure in Roll Call Votes

• In Event: Political Parties and Legislatures

Abstract

Assessing what roll call votes can tell us about legislator
preferences has proved to be an important conundrum in legislative
studies. This is due to two reasons: first, roll call votes are likely
to occur for very specific votes in most parliaments, and second,
having a roll call vote (i.e., a public record of how a legislator has
voted) will influence a legislator's voting behavior. Drawing on a
unique dataset comprising all votes from the two chambers of the Swiss
parliament, some of which were automatically roll called while for
others legislators requested them, we are able to identify the effects
of both roll call votes and selecting particular topics for roll call
votes. As we also have information on who requested the roll call, we
can distinguish among motivations for calling a roll call. We find,
based on an extension of the two cut-point IRT model (Clinton, Jackman
and Rivers, 2004), that members of the Swiss lower house support more
leftist positions when their voting behavior is exposed to scrutiny,
compared to situations when their behavior is not visible. In the
upper house, however, the left and right are affected differently by
the publicity of their voting. Thus, we can demonstrate that
inferences drawn from roll call votes, when these do not cover the
full universe of voting decisions, lead to biased inferences regarding
the ideal-points of legislators.

Authors

• Simon Hug, University of Geneva

• Reto Wuest, University of Geneva