Coalition Agreements and Party Preferences: A Principal Components Analysis Approach

Abstract

How do coalitions’ policies and the preferences of their member parties relate? Attempts to answer this question have looked at the connection between party manifestos and the policy intentions of the government as expressed in the coalition agreement or declaration. This paper tries to make a twofold contribution to this literature. First, unlike other studies that rely on alternative techniques, we defend the use of Principal Components Analysis (PCA) as an appropriate method to automatically evaluate how similar/different are the documents measuring party preferences and the coalition agreement and obtain the distances between them, without the need of an ideological scaling. Second, in addition to party manifestos, we also use parliamentary speeches in the investiture debate to capture the preferences of parties. Using data from the Spanish regional coalition governments between 2005 and 2011, we find that i) the use of PCA does lead to the emergence of substantively and statistically significant relationships between party preferences and coalition agreements, and ii) the use of parliamentary speeches tends to provide more plausible results than manifestos, which signals speeches as relevant documents for the study of coalition politics. In particular, we show that it is difficult to predict which specific member party will succeed at bringing the agreement closer to its preferences, but the priority seems to be moving the agreement away from the opposition parties. Interestingly, we also find that there is a specially strong connection between the candidate speech in the investiture debate and the coalition agreement. ∗Preliminary draft: comments welcomed. This study acknowledges the research support from the project Coalition Agreements and Government Formation in Spain, 1979-2011 (CSO2010-16337). †Department of Constitutional Law and Political Science, University of Barcelona, Diagonal 684, 08034 Barcelona, Spain. E-mail: afalcogimeno@ub.edu ‡Department of Constitutional Law and Political Science, University of Barcelona, Diagonal 684, 08034 Barcelona, Spain. E-mail: vallbe@ub.edu