Recently, many scholars have addressed the decline of neo-corporatism, as institutions for concertation and key economic actors struggle to maintain their former central role in policy-making. Most of these analyses have focused on the functioning of neo-corporatist institutions, while ignoring broader dynamics within the interest group population. This lack of attention to organizational dynamics within the interest group system is problematic, as it inhibits a sound assessment of mobilization bias in neo-corporatist countries. Our paper assesses to what extent the density and diversity of the interest group population is reflected in official neo-corporatist institutions, relying on a novel dataset of interest populations in two neo-corporatist countries, Belgium and the Netherlands. While the interest system of both countries is affected by the legacy of neo-corporatism, societal and economic factors result in a rather crowded interest group landscape, which does not seem to be reflected in official corporatist institutions.
