On the road to policy success: When and why do interest groups gain party support?

Interest groups are more likely to be successful in attaining their preferences when political parties support them. Given a supportive party political environment, different kinds of groups may find their policy preferences translated into public policy more or less often, and inequalities in the interest group system may be moderated – for better or worse – by the party system. Interest groups thus have a clear incentive to strategically interact in their party political environment and actively lobby political parties to adjust their positions to align with their own. But which groups are more successful in doing so? In this paper I develop a structural- and a meso-level explanation for this question that predict a business group advantage or an even playing field between business and social groups respectively. I test these hypotheses with data on changes in party support for interest group positions (22 parties, 120 interest groups) in Germany, the Netherlands, and the United Kingdom. Controlling for alternative factors, such as explanations of party position change found in the party politics literature, I find evidence of a business group advantage that is due to structural- and meso-level factors. My findings have implications for the literature on the relation between interest groups and parties, business group advantages in politics, and party position change.