The Arithmetics of partisanship and policy outcomes in parliamentary democracies

Abstract

Empirical assessments of partisan models of politics have primarily focused on the relationship between government composition and policy outcomes. However, we argue that it is necessary to take parties outside government into account because their preferences also shape policy in parliamentary democracies. We show that a measure of parliamentary partisanship based on the preferences and bargaining power shares of all legislative parties outperforms the more traditional measure of government partisanship in explaining policy outcomes. In particular, we find that this is the case for public social spending and political decentralization.