Hanna Bäck, Thomas Persson, Henk Erik Meier
Party Size and Portfolio Payoffs. The Proportional Allocation of Ministerial Posts in Coalition Governments

Journal of Legislative Studies, 2009: Heft 15, S. 10-34
ISSN: 1357-2334

Over thirty years ago, Browne and Franklin (1973) 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 between party size and portfolio payoffs. To fulfil this aim, a small-n analysis is performed. By analyzing the predictions from a statistical analysis, two predicted cases are selected; the centre-right coalition government that was formed after the 1976 Swedish election, and the centre-right coalition that was formed after the 1994 German election. In these case studies two hypotheses are tested: that the proportional payoff is the result of the workings of a social norm, or that parties receive payoffs according to their bargaining strength. Data indicates that parties will choose to stress that a proportionality principle should be followed if they can gain from doing so. Consequently, data is more in line with the bargaining hypothesis.