Replication data for: 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.

在美国众议院与参议院中，每一项法案均由唯一的议员作为主提案人（sponsor）。此外，议员可通过联署法案，公开表达对该项法案的支持。主提案议员与联署议员构成的联署网络（cosponsorship network），能够反映议员之间潜藏的社会关联结构。本研究通过多项统计指标对该联署网络进行刻画，旨在证明其运行特征与近期学界已研究的其他大型社会网络存在显著差异。具体而言，该联署网络的密度远高于其他同类网络，且其整体结构特征似乎受到制度安排与策略动机的共同影响。此外，本研究还证明，一种被命名为“关联度（connectedness）”的加权接近中心性（weighted closeness centrality）指标，可用于识别具有影响力的议员。