Whether interest representation is biased has been a recurrent theme in the study of interest groups. Recent years have witnessed a revival of large n studies which systematically study how active different types of interest groups are in the policy making processes of the European Union and beyond. Such studies have moved the research agenda forward. However, to examine whether representation is biased we need not only examine which groups are active but how easy it is for different types of groups in the population of interest groups as a whole to get active. Moreover, we need not only know the activity levels of different types of groups, but also how successful different groups are in getting access to the fora where crucial policy-making decisions are made. We address exactly these two points by building a model that aims at explaining what conditions the likelihood that groups in the broader population of interest groups are granted access to advisory, policy-making committees. In explaining access we pay attention to both the characteristics of the groups themselves as well as the policy areas in which they are active. Our predictions are tested in a cross-sectional analysis of the European Union, where we link data on the EU population of interest groups with data on the membership of all the advisory committees of the European Commission.
