I conducted a meta-review of policy diffusion studies that focus on the American states. By casting a wide net using Google Scholar and Web of Science, I identified all (to my knowledge) studies published between 1990 and 2018 that referred to “policy diffusion” and “berry and berry.” Berry and Berry are important because their 1990 study of state lotteries introduced the unified model of policy diffusion. Essentially, this model combined the internal characteristics of states with influences external to the states to explain policy adoption. Over time, scholars also recognized that the attributes of the policy innovations themselves condition how far and how quickly they spread. Continue reading →
This quarter’s highlights collection focusses on the popular theme of policy diffusion, bringing new analyses offering fresh perspectives on this extensive area of scholarship.
In our first featured article on policy diffusion, Daniel Mallinson continues his efforts in offering the most comprehensive analysis to date on how policy innovation diffuses across American states. Although hundreds of articles have tackled the fundamental question of why innovative policies spread, none has fully grappled with the scope of their disparate results.
To fill that gap, this article presents a state-of-the-art systematic review and meta-analysis of how policy innovation flows from US state to US state and the average effects of commonly used variables in the study of policy diffusion. In doing so, it highlights important biases in the research and makes recommendations for addressing those biases and increasing international collaboration on policy innovation research and results. Continue reading →