The Difference Between Real and Potential Power: Voting Power, Attendance and Cohesion. ZEI Discussion Paper: 2004, 130

[From the Introduction]. Applying power indices to the political process of the European Union has become fashionable. An increasing range of scholars has applied power indices to studying the institutions of the European Union (EU). However, their work has not gone without criticism. Critics argue that the use of power indices is of little value, since they ignore the preferences of the actors, such as party groups, and also the political dynamics of the decisionmaking processes, such as the EU legislative procedures (see particularly Garrett and Tsebelis 1996, 1999, Tsebelis and Garrett 1996). Advocates of power indices reply by arguing that one cannot know the preferences of the relevant actors in all possible contingencies. We do not always know the preferences of the actors, but we can still say something meaningful about their potential influence (see for example Lane and Berg 1999, Holler and Widgrén 1999).... This article analyses the distribution of voting power in the 1999-2002 EP, taking into account differential levels of attendance and cohesion among party groups. It does so – using the Shapley-Shubik -index (Shapley and Shubik 1954) – for two different kinds of votes: First, votes taken under absolute majority rule (i.e. a majority of all MEPs is necessary for a proposal to pass), second – and this is nowadays the empirically more relevant case – votes taken under simple majority rule (i.e. only a majority of the votes cast is necessary for a proposal to pass). However, before we start the actual discussion of the distribution of power, a few remarks concerning party groups in the EP – and especially their levels of cohesion and attendance – seem appropriate