Party Size and Portfolio Payoffs: The Proportional Allocation of Ministerial Posts in Coalition Governments

Abstract

Over 30 years ago, Eric Browne and Mark Franklin demonstrated that parties in a coalition tend to receive portfolio payoffs in almost perfect proportionality to their seat share. Even though this result has been confirmed in several studies, few researchers have asked what the underlying mechanism is that explains why parties receive a proportional payoff. The aim of this paper is to investigate the causal mechanism linking party size and portfolio payoffs. To fulfil this aim, a small-n analysis is performed. By analysing the predictions from a statistical analysis of all post-war coalition governments in 14 Western European countries, two predicted cases are selected, the coalitions that formed after the 1976 Swedish election and the 1994 German election. In these case studies two hypotheses are evaluated: that the proportional distribution of ministerial posts is the result of a social norm, and that parties obtain payoffs according to their bargaining strength. The results give no support to the social norm hypothesis. Instead, it is suggested that proportionality serves as a bargaining convention for the actors involved, thus rendering proportional payoffs more likely.