Diffusion or Confusion? Modeling Policy Diffusion with Discrete Event History Data

In a review of the literature on policy diffusion in the states, Berry and Berry (1999) conclude that the “gold standard ” methodological approach to the empirical modeling of these processes is discrete event history analysis. I concur, but find that the literature largely ignores several important issues in the proper specification of these models, including choice of functional form, modeling different mechanisms of diffusion, modeling duration dependence, and spatial autocorrelation in the cross-sections. I use data from Berry and Berry’s (1990) classic study of the diffusion of state lotteries to suggest possible improvements to this research