Conceptualizing Network Externalities in Policy Diffusion.

Since Walker(1969) and Gray(1970) have pioneered in diffusion and innovation, for recent decades, a lot of scholars have paid attention to policy diffusion. Even though a couple of studies investigate the mechanisms of policy diffusion (Berry and Berry, 1990:1999; Shipan and Volden, 2008; Brooks, 2007; Gray, 1973, Mintrom and Vergari, 1998), these existing literatures do not examine network effect in policy diffusion in detail. Therefore, this paper takes notice that there might be network externalities in policy diffusion mechanisms, and through network externalities we might investigate the dynamic change and its process due to network in policy diffusion in more detail. Network externalities can constrain or stimulate policy diffusion. Specifically, this paper tries to theoretically scrutinize whether there are network externalities and how they happen in policy diffusion mechanisms. Political scientists and public administrators have until now overlooked network externalities of public policy diffusion. In order to more systematically explore network effect in policy diffusion, overcoming the limitation of path dependency, this paper first incorporates both path dependency and network externalities in policy diffusion. And then, the authors then build a policy diffusion mechanism, considering network externalities. Based on this mechanism and the natures of policy diffusion, the authors build propositions to investigate the impact of network externalities on policy diffusion. Lastly, this paper closes with discussion and policy implication. ..PAT.-Unpublished Manuscript [ABSTRACT FROM AUTHOR]