Spatial Models of Party Competition Applied
An application of spatial models of party competition presupposes the construction of policy spaces which encompass the important policy issues of an election. These are the basis of policy voting by the electorate and of strategic position taking by parties. In addition to policy voting, individual vote functions have to include party valences and long-term commitments of voters to parties. After having estimated such vote functions for several Bundestag elections, our aim is to study equilibrium dynamics of party competition under the impact of mixed electoral systems. For pure electoral systems the folk wisdom is that first past the post induces centripetal party movements, and proportional representation induces centrifugal positioning, especially of low-valence parties. Our research question is how voters respond to the opportunity to cast two ballots and how parties come to terms with the possibly differing equilibrium dynamics of mixed-member electoral systems.
In the first year of this DFG funded project we developed our basic spatial model to analyse party competition at Bundestag elections, forthcoming in the Journal of Theoretical Politics: “Combining ideological and policy distances with valence for a model of party competition in Germany 2009”. Starting from there, we identified diverging equilibrium dynamics of first and second ballot voting in the German mixed-member electoral system (conference paper for 2015 MPSA Convention), analysed the impact of party and district candidate valences as measured by exit-polls in two constituencies on first and second vote (in press in Zeitschrift für Parlamentsfragen), and studied possible contamination effects of presence or absence of AfD district candidates on second ballots in 2013.