Catch Me If You Can Recovering Sophisticated Voting in the Lower House of Switzerland ∗ ( Word Count : 8 ’ 600 )

There is wide theoretical coverage of sophisticated voting despite a clear empirical gap. There are only a handful empirical examples of sophisticated voting which are documented. There is also no systematic searching approach to recover such cases. This paper offers the first systematic approach to identify votes where sophisticated voting seems likely. The algorithm developed here cannot state if sophisticated voting occurred or not, but it can guide scholars to cases where it is promising to focus on. The proposed algorithm relies heavily on the Bayesian roll call analysis and on a probabilistic choice model. First, ideal points are estimated on a restricted sample, ensuring that the assumptions are not violated. In a second step, a subsample of ideological groups is used to estimate the ideological parameters of a proposal. Finally, based on ideal points of legislators and ideological parameters of proposals it is possible to identify highly atypical voting behavior. The algorithm flags fifteen cases of potential sophisticated voting out of 1281 votes. ∗Paper prepared for the Annual Swiss Political Science Meeting, St.Gallen January 2009.