Strategic voting in German constituencies

We investigate strategic voting at German Bundestag elections. The common intuition about strategic voting holds that supporters of small party candidates split their ticket and cast a constituency vote for the candidate of a viable large party. We show that there is more potential for strategic voting than previously admitted. Based on the multiparty calculus of voting framework, we formulate a decision-theoretic model that allows us to take the full range of situations into account, that voters may encounter in their local constituencies. Applying this model to survey data from the 1998 and 2002 federal elections, we find that voters make use of sophisticated balloting, given the chance to influence the outcome of the constituency election. While the focus of this paper is on Germany, the approach we take is applicable to single seat elections in other countries as well.