The Impact of Party Supply and Variations in Electoral Rules on Strategic Voting

In this paper we study the impact of party supply and variations in electoral rules on strategic voting. Starting from a precise definition of strategic voting that takes voters' preferences, their evaluation of each party's chances to get elected and their final vote choice into account, we distinguish three types of possible strategic behavior in elections. Making use of panel data from an original survey covering three subsequent elections in Bavaria (regional and national elections in 2013 and the European election in 2014), we study how the use of different electoral rules (two vote system with 5% threshold vs. pure list vote without threshold) as well as a changing supply side (one newly formed viable party in the national and European elections and one party viable at the regional level only) influence individual voters' party preferences, their evaluation of the parties' chances to gain representation, as well as their decision to vote strategically. Our paper contributes to the analysis of individual electoral behavior and the impact of electoral institutions and party supply on preference formation as well as the willingness and ability of voters to cast a strategic vote.