Connecting the Congress: A Study of Cosponsorship Networks (original) (raw)
Related papers
Legislative Cosponsorship Networks in the U.S. House and Senate
In the US House and Senate, each piece of legislation is sponsored by a unique legislator. In addition, legislators can publicly express support for a piece of legislation by cosponsoring it. The network of sponsors and cosponsors provides information about the underlying social networks among legislators. I use a number of statistics to describe the cosponsorship network in order to show that it behaves much differently than other large social networks that have been recently studied. In particular, the cosponsorship network is much denser than other networks and aggregate features of the network appear to be influenced by institutional arrangements and strategic incentives. I also demonstrate that a weighted closeness centrality measure that I call "connectedness" can be used to identify influential legislators.
Community Structure in Congressional Cosponsorship Networks
We study the United States Congress by constructing networks between Members of Congress based on the legislation that they cosponsor. Using the concept of modularity, we identify the community structure of Congressmen, as connected via sponsorship/cosponsorship of the same legislation, to investigate the collaborative communities of legislators in both chambers of Congress. This analysis yields an explicit and conceptually clear measure of political polarization, demonstrating a sharp increase in partisan polarization which preceded and then culminated in the 104th Congress (1995-1996), when Republicans took control of both chambers. Although polarization has since waned in the U.S. Senate, it remains at historically high levels in the House of Representatives.
We examine the social network structure of Congress from 1973-2004. We treat two Members of Congresas directly linked if they have cosponsored a bill together. We then construct explicit networks for each year using data from all forms of legislation, including resolutions, public and private bills, and amendments. We show that Congress exemplifies the characteristics of a "small world" network and that the varying small world properties during this time period are strongly related to the number of important bills passed.
Measurement and theory in legislative networks: The evolving topology of Congressional collaboration
Social Networks, 2014
The examination of legislatures as social networks represents a growing area of legislative scholarship. We examine existing treatments of cosponsorship data as constituting legislative networks, with measures aggregated over entire legislative sessions. We point out ways in which the adoption of models from the social networks literature directly to legislative networks aggregated over entire sessions could potentially obscure interesting variation at different levels of measurement. We then present an illustration of an alternative approach, in which we analyze disaggregated, dynamic networks and utilize multiple measures to guard against overly measure-dependent inferences. Our results indicate that the cosponsorship network is a highly responsive network subject to external institutional pressures that more aggregated analyses would overlook.
A network analysis of committees in the U.S. House of Representatives
Computing Research Repository, 2005
Network theory provides a powerful tool for the representation and analysis of complex systems of interacting agents. Here we investigate the United States House of Representatives network of committees and subcommittees, with committees connected according to "interlocks" or common membership. Analysis of this network reveals clearly the strong links between different committees, as well as the intrinsic hierarchical structure within the House as a whole. We show that network theory, combined with the analysis of roll call votes using singular value decomposition, successfully uncovers political and organizational correlations between committees in the House without the need to incorporate other political information.
Networks in the Legislative Arena: How Group Dynamics Affect Cosponsorship
Legislative Studies Quarterly, 2011
In this study, we explore the determinants of cosponsorship activity within state legislatures. Previous literature has generally focused on individual level characteristics to explain legislative behavior, placing little emphasis on how collaboration and mutual interests shape the agenda-setting process. Utilizing a social dynamics framework, we develop and test a model of the interplay of the activities of sponsorship and cosponsorship that includes both individual-level and social network characteristics as determinants of agenda-setting behavior. We find several consistent factors that influence the frequency of activity: 1) ideological distance (the further the distance between the primary sponsor and a legislator, the less likely that legislator will cosponsor a measure) 2) the proximity of legislators' districts (legislators are more likely to cosponsor measures that are sponsored by legislators from neighboring districts) 3) homophily (legislators who share similar characteristics such as race, gender, and ethnicity are more likely to cosponsor each other's measures) and 4) transitivity (legislators who cosponsor the legislation sponsored by their colleagues are more likely to attract those colleagues as cosponsors on their own set of sponsored measures). Further, our analysis of network structure suggests that legislators in each state are organized into relatively small groups, exhibiting a "clique-like" quality, whereby members coalesce around several common traits and cosponsor each other's measures.
Explaining Policy Ties in Presidential Congresses: A Network Analysis of Bill Initiation Data
Political Studies, 2012
Policy networks formed by co-authoring and co-sponsoring bills reflect one of the most important types of connection legislators develop while in office. We expect that in presidential countries, the probability of a tie between two legislators should be influenced by partisan membership, territorial linkages and the policy areas in which they develop expertise. Given the complex nature of relational data and the particular characteristics of bill initiation networks, we propose a new approach – bootstrapping an exponential graph model using augmented data reflective of the frequency of ties – to address the challenges of thinning dense networks.
Journal of Complex Networks, 2016
We study community structure in time-dependent legislation cosponsorship networks in the Peruvian Congress, and we compare them briefly to legislation cosponsorship networks in the US Senate. To study these legislatures, we employ a multilayer representation of temporal networks in which legislators in each layer are connected to each other with a weight that is based on how many bills they cosponsor. We then use multilayer modularity maximization to detect communities in these networks. From our computations, we are able to capture power shifts in the Peruvian Congress during 2006-2011. For example, we observe the emergence of 'opportunists', who switch from one community to another, as well as cohesive legislative communities whose initial component legislators never change communities. Interestingly, many of the opportunists belong to the group that won the majority in Congress.
2011
Abstract This project examines how interest groups create partisan connections among US House members. Although the rise of ideologically motivated groups has been identified as a potential cause of legislative partisanship, there is very little research on how interest groups affect the nature of partisan coalitions. We consider how interest group donation strategies create connections between legislators and how the resulting networks affect the nature of lawmaking in the House.
Working paper. Carnegie Mellon …, 2008
Why do members of Congress choose to cosponsor legislation proposed by their colleagues? What can we learn from their patterns of cosponsorship? Legislative scholars are increasingly interested in understanding why member of Congress cosponsor legislation proposed by their colleagues, and in explaining the patterns of such cosponsorship. These are fundamentally questions about relationships, but, unfortunately, most methods of statistical analysis with which researchers, even methodologists, are familiar are ill-suited to relational data, in which observations are heavily interdependent. Previous empirical work on cosponsorship in the House and Senate has suered from two main aws. First, it has used statistical tools that ignore the systematic clustering of observations. Second, it has overemphasized large-scale inuences such as party and state or region, at the expense of more subtle social factors that operate at a lower order of magnitude.