Legislative Co-sponsorship: Interest Groups as Hidden Links?

Interacting with MPs is critical for interest groups in terms of agenda-setting and policy influence and, vice versa, MPs rely on interest groups for policy information and resources. This study focuses on a crucial aspect of this symbiotic relation between interest groups and MPs. It investigates whether MPs' affiliations to interest groups influence MPs agenda-setting behavior in parliament. It combines the literature on interest groups, parliamentary behavior, and legislative networks. A first theoretical expectation is that MPs with formal ties to interest groups, within a specific policy domain, are more likely to co-sponsor legislative proposals in this domain than MPs not affiliated to these interest groups. A second expectation is that MPs with similar profiles in terms of their interest groups ties co-sponsor their respective legislative proposals. These hypotheses will be tested empirically with data on MPs interest group ties and MPs behavior in terms of co-sponsoring legislative proposals in the Swiss Parliament. Simple network measures such as degree centrality will capture the relations between groups and MPs. The information on which MPs have ties to which interest groups stems from the official register of the Swiss Parliament. Co-sponsorship activity of MPs as well as co-sponsorship ties between MPs are assessed in a network. The respective data stems from the official database of the Swiss Parliament. The analysis is based on a statistical model for network data (ERGM), and will control for additional explanatory variables of co-sponsorship behavior such as MPs' party membership, legislative committee assignments, electoral districts, seniority in Parliament, gender, etc. Investigating the influence of interest groups on MPs agenda-setting activities is an important theoretical and normative topic, as it relates to the broader question of which interests MPs represent in parliament. If the hypothesized mechanisms are observed, this means that MPs promote the policy agenda of interest groups instead of representing the preferences of their electoral constituency. Such a discrepancy between electoral constituency and group preferences could be a concern for representative democracy. From a methodological point of view, it is also an interesting research design since ties between MPs and interest groups measure groups' access to the parliamentary venue, and the respective MPs’ co-sponsorship of legislative proposals capture groups' influence on agenda-setting and policy-making. This study will thus deliver some answers to the question (formulated in the call for papers) whether party and group agendas overlap.