We study the cohesion within and the coalitions between political groups in the Eighth European Parliament (2014–2019) by analyzing two entirely different aspects of the behavior of the Members of the European Parliament (MEPs) in the policy-making processes. On one hand, we analyze their co-voting patterns and, on the other, their retweeting behavior. We make use of two diverse datasets in the analysis. The first one is the roll-call vote dataset, where cohesion is regarded as the tendency to co-vote within a group, and a coalition is formed when the members of several groups exhibit a high degree of co-voting agreement on a subject. The second dataset comes from Twitter; it captures the retweeting (i.e., endorsing) behavior of the MEPs and implies cohesion (retweets within the same group) and coalitions (retweets between groups) from a completely different perspective. We employ two different methodologies to analyze the cohesion and coalitions. The first one is based on Krippendorff’s Alpha reliability, used to measure the agreement between raters in data-analysis scenarios, and the second one is based on Exponential Random Graph Models, often used in social-network analysis. We give general insights into the cohesion of political groups in the European Parliament, explore whether coalitions are formed in the same way for different policy areas, and examine to what degree the retweeting behavior of MEPs corresponds to their co-voting patterns. A novel and interesting aspect of our work is the relationship between the co-voting and retweeting patterns.
The European Parliament has be? come one of the most powerful insti? tutions in the European Union. Mem? bers of the European Parliament (MEPs) can now enact legislation, amend the European Union budget, veto the nominee for the European Union Commission President, and censure the Commission. But, we know little about what determines MEPs' voting behavior. Do they vote according to their personal policy preferences? Do the EP parties force MEPs to toe the party line? And, when national party and EP party preferences conflict, which way do MEPs respond?to the principals who control their election (the national parties) or the principals who control their influence in the EP (the EP par? ties)? The results reported here show that national party policies are the strongest predictors of voting behav? ior in the EP. How cohesive are political parties in the European Parliament? What coalitions form and why? The answers to these questions are central for understanding the impact of the European Parliament on European Union policies. These questions are also central in the study of legislative behaviour in general. We collected the total population of roll-call votes in the European Parliament, from the first elections in 1979 to the end of 2001 (over 11,500 votes). The data show growing party cohesion despite growing internal national and ideological diversity within the European party groups. We also find that the distance between parties on the left–right dimension is the strongest predictor of coalition patterns. We conclude that increased power of the European Parliament has meant increased power for the transnational parties, via increased internal party cohesion and inter-party competition. We examined how voting behavior in the European Parliament changed after the European Union added ten new member-states in 2004. Using roll-call votes, we compared voting behavior in the first half of the Sixth European Parliament (July 2004-December 2006) with voting behavior in the previous Parliament (1999–2004). We looked at party cohesion, coalition formation, and the spatial map of voting by members of the European Parliament. We found stable levels of party cohesion and interparty coalitions that formed mainly around the left-right dimension. Ideological distance between parties was the strongest predictor of coalition preferences. Overall, the enlargement of the European Union in 2004 did not change the way politics works inside the European Parliament. We also looked at the specific case of the controversial Services Directive and found that ideology remained the main predictor of voting behavior, although nationality also played a role.  . The members of the European Parliament are elected in nationally organized and domestically oriented polls; however, in the Strasbourg Assembly they form transnational Party Groups or Europarties. The Rules of Procedure require such formations for the functioning of the Assembly, but Party Groups are much more than procedure requisites. They assemble elected representatives of national parties which share a consistent similarity in political ideologies and strategies. Party integration is a decisive development in the unification process of the Western European countries and it is expected to come from the Party Groups experience. The paper analyses such an issue by examining roll-call votes. Data include a systematic sample of votes cast during the first and second elected Parliament. The research looks into two fundamental items: (a) Party Group cohesion (an index of agreement is used to measure it); (b) voting line-ups of Party Groups. The aim is to point out the most important political cleavages and issues of the Community political system.