The network analysis literature described above has mostly been developed in sociology and anthropology. In political science, a largely separate body of research has developed to study ‘‘policy networks.’’ The policy network literature itself arose at the conXuence of several streams of research. Among the earliest precursors to the policy network literature was Heclo and Wildavsky’s (1974) study of the British Treasury Department, which uncovered the importance of personal networks between civil servants and politicians as an important factor shaping policy decisions. In the USA, development of the policy network concept arose out of work on ‘‘sub-governments’’—the idea that policy-making and implementation were controlled by a select group of agencies, legislators, and interest groups. Working in this tradition, Heclo (1978) coined the term ‘‘issue network’’ to describe more diVuse forms of linkage than implied by the terms ‘‘sub-government’’ or ‘‘iron triangle.’’ A closely related stream of European work on policy networks grew out of studies of corporatism and interest intermediation (Katzenstein 1978; Lembruch 1984). A second stream of research arose from an international group of researchers studying complex interorganizational relationships in government in the 1970s (e.g. Hanf and Scharpf 1979). This work emphasized that policy- making and implementation required complex coordination and negotiation among many diVerent actors. A third stream of policy network research grew out of work on ‘‘community power studies,’’ which essentially examined the social structure of politics in cities. Work by Lauman and Pappi (1976), in particular, advanced this into the study of policy networks.
All of these approaches combine two somewhat opposed images of political organization and process: all of them stress that political structure and process is highly diVerentiated, comprising the participation of a diverse range of actors; the opposing image suggests that these actors are linked together around their mutual interest or interdependence in speciWc policy domains. Thus, the network approach has the advantage of representing the ideas of both pluralists (empha- sizing diVerentiation) and elite theorists (emphasizing connectivity).
The next generation of policy network research began to clarify diVerences internal to networks and to articulate mechanisms by which they worked. Notably, Rhodes (1985) distinguished Heclo’s concept of ‘‘issue networks’’ from ‘‘policy communities’’ in terms of the stability and restrictiveness of networks. He also articulated a ‘‘power-dependence’’ perspective that provided a framework for thinking about why and how networks were formed and how they operated. In a recent review of the policy network literature, Rhodes (2006) contrasts this ‘‘power-dependence’’ approach with the rational choice institutionalist approach to policy networks developed by Scharpf (1997).
Some of the policy network literature has drawn on the network analysis techniques described above. Laumann and Knoke’s (1987) massive study of Ameri- can policy networks and Knoke, Pappi, Broadbent, and Tsujinaka’s (1996) comparative study of labor policy networks oVer important examples.
