Why resist the temptation to apply power indices to the European Union?

The temptation to apply power indices to decision-making in the European Union should be resisted for two reasons. First, power index approaches either ignore the policy preferences of relevant actors in the EU or incorporate them in ways that generate unstable and misleading results. Second, no matter how sophisticated, power indices cannot take into account the strategic properties of the procedures that govern Europe's legislative processes, especially concerning changes in the institutional location of agenda-setting power. Proponents have responded to our criticisms of earlier power index research with ingenious efforts to include functional substitutes for institutions and preferences. The problems with power indices, however, are congenital and cannot be adequately addressed without moving to a non-cooperative game theoretic framework.