Universität Mannheim / Sowi / LSPOL3 / english / Research / Intra-Party Heterogeneity

Intra-party Heterogeneity and its Political Consequences in Europe

In much of the literature on government formation and party behaviour, parties are treated as "unitary actors". This assumption is problematic since parties represent divergent interests of various members in several regional and organizational units, and such ideological heterogeneity can have important political consequences. This project aims at measuring ideological heterogeneity within parties, and at exploring its causes and consequences. On the basis of theories on electoral systems and party systems, political socialisation, party organisation and the principal-agent approach, we explain varying levels of intra-party heterogeneity by taking individual features of MPs and ministers as well as institutional factors into account. In addition, the project explores some of the main implications of intra-party heterogeneity. It has been argued that intra-party heterogeneity influences the power and behaviour of political actors, and patterns of intra-party conflict should thus have important consequences on political decision-making. In this project we focus more specifically on the effect of ideological heterogeneity on parties’ electoral performance, government formation and the allocation of cabinet offices. The project gathers data from parliaments in nine West European countries (Austria, Belgium, France, Germany, Italy, the Netherlands, Spain, Sweden, and the United Kingdom). Our main source of information is parliamentary speeches of members of Parliament (MPs), which are analysed using computerised methods of content analysis. Understanding the causes and effects of intra-party heterogeneity is important for our knowledge about the functioning of parliamentary democracies in general and for explaining behaviour and decision-making of partisan political actors in particular.