Daniel J. Mallinson
Since the 1960s, political scientists from across the globe have been studying how and why policies spread. This substantial body of research begs the question, what have we learned? My project aims to answer that question, at least in part. It finds both substantial growth in the literature and gaps that remain to be filled.
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