Negotiating policy support: Explaining bias in interest group influence on legislative party groups across policy areas

How parties interact with interest groups may matter for the quality of political representation. Legislative party groups regularly get input from numerous interest groups trying to influence the priority and design of policy proposals, but individual party groups are likely to listen more to some groups than others. This creates a bias in interest group influence on individual parties. In this paper, we shed light on what explains such bias in interest group influence on legislative party groups, and test possible party level explanations across different policy areas in Western democracies. Based on theory of parties as rational goal-seeking actors, we hypothesize that bias in interest group influence will decrease when party salience increases because parties will then be more concerned about scaring away voters. It will be especially important for parties to emerge as serious and knowledgeable on the issue. Information provided by different interest groups becomes more valuable to avoid being scrutinized for bad policy proposals. Thus, parties try to find solutions that satisfy different groups without cross-cutting party decisions. The hypothesis is tested by combining the PAIRDEM interest group survey data set with party salience data from the Manifesto Project. Multiple regression analysis controlling for media salience, party size and country fixed effects give some support for the proposed hypothesis. The findings indicate that legislative party groups do seek to balance out different concerns among interest groups on policy areas of high party salience.