More reasons to resist the temptation of power indices in the European Union

Jan-Erik Lane and Sven Berg, and Manfred Holler and Mika Widgren, agree tha t power index analysis of the EU cannot take into account its institutional structure. For us, this is a sufficient condition for its failure as a res earch program. Nonetheless, they go on to argue that power indices are bett er suited than our analysis to address questions of institutional design un der conditions of uncertainty. We demonstrate, however, that the way they m odel uncertainty (outcomes are uniformly distributed across the possible 's tates of the world') means that their conclusions depend heavily on the par tition of these states of the world. As a result, power-index-based analyse s of institutional design are not informed by;the factors that should be in cluded (institutions and strategies) and instead rely on a priori mathemati cal formulas and analysts' questionable assumptions about the partition of future states of the world.