Abstract
The question of interest group influence is central for both scholars interested in studying policy-making in the EU and those concerned with the legitimacy of decision-making in that entity. Many hypotheses exist that stress a series of factors possibly shaping interest group influence. Nevertheless, only few studies have tried empirically to examine these hypotheses for the case of the EU. What is more, existing empirical studies report contradictory findings. To help researchers advance upon this state of the art, three obstacles that impede research dealing with interest group influence in the EU are discussed: defining the terms ‘power’ and ‘influence’; accounting for different pathways to influence; and measuring influence. In addition to this, several ways to address these obstacles are advanced: by taking a pragmatic approach with respect to defining influence and power; by being conscious that actors may use different pathways to influence when drawing conclusions about interest group influence; and by combining different methods when measuring influence.