A Geometric Model of Elections in Five Federal Democracies

Abstract

In an analysis of 1,825 state or provincial election outcomes in five federal democracies the rate of decay of incumbency (K) serves to partition the distribution of the vote for the incumbent party, the party of the head of government, between those who win a subsequent term and those who do not. In conjunction with the mean and standard deviation of the distribution, the weighted mean of the vote in re-election and defeat is identified. The model's predictions are generally within 2-3 percentage points of the actual outcome.