Measurement and theory in legislative networks: The evolving topology of Congressional collaboration

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 direct application of models from the social networks literature 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.