Understanding interest groups - legislators ties on social media networks: the case of the European Parliament.

Social media nowadays are powerful tools for communication, information gathering and coalitions building, which interest groups use as part of their lobbying repertoires to influence policy. However, social media also present important challenges, e.g., managing high-traffic information flow, information overload, enhanced levels of public scrutiny, and potential reputational costs. This motivates interest groups to be both rational and purposeful regarding their social media usage, especially when connecting to decision-makers that possess an electoral and representation mandate such as legislators. As such, interest groups decide to follow and connect on social media with some legislators, while ignoring others. What explains this decision-making process remains a question. We address this puzzle and focus empirically on Twitter, a social media platform that established itself as a key political communication tool employed by elected officials and interest groups. We elaborate a theoretical argument that emphasises on the one hand the importance of the institutional roles performed by legislators as political and policy (expert) actors, and, on the other hand, on the different set of incentives interest groups have to use Twitter as an electoral-oversight and information-gathering device. We test our argument on a unique dataset recoding information Twitter ties between more than 7,000 interest groups and the legislators serving the eighth European Parliament (EP8). With the help of bipartite Exponential Random Graph Models (ERGMs), we examine the extent to which key characteristics of MEPs as political and policy actors shape interest groups’ decision about which legislators to follow on Twitter, while controlling for network- and actor-level factors. We thus contribute to the emerging and sparse literature on lobbying and social media in Europe and beyond, and the well-established research on the formation and dynamics of policy and political networks.