A computational model of multi-party electoral competition with coalition formation

This paper assesses coalition formation and electoral competition in a single agent-based computational model. By employing the simple assumption that parties’ past positions matter more for parties that are members of a governing coalition than they matter for parties that are outside the government I provide a connection between the electoral process and government formation. Electoral competition plays out in two dimensions, while the government formation process is based on ideological proximity between parties which is in turn an outcome of the electoral process. In analyzing the model’s properties I show that the probability of being included in a coalition increases in the number of parties in the electoral arena and the shares a party commands. Having been a member of a governing coalition in t-1 increases the chances of being included in the new coalition. The chances of being a member of the coalition decrease in the distance between a party and the means of voters’ preference distributions. Parties that were members of a coalition are also more successful in the electoral arena.