The Diffusion of Policy Perceptions: Evidence from a Structural Topic Model

Abstract: Policy diffusion occurs when policies in one unit (e.g., states, cantons, cities) are influenced by the prior adoption of policies in other units. Although numerous studies have convincingly shown that policy adoption is a function of previous adoptions in other units, they have, with very few exceptions, generally ignored a crucial step in the diffusion process—namely, how political units perceive the policies that they are considering adopting. This policy perception plays a crucial role in linking the actions of previous units with the potential actions in other units. In this paper we focus on the link between prior adoptions and policy perceptions, both by identifying the mix of perceptions and by examining the link between prior adoptions and policy perceptions. We study these perceptions in the area of restrictions on smoking in U.S. states. Our analysis draws upon an original dataset of almost half a million articles published in thirty American newspapers between 1996 and 2014 and uses structural topic models to estimate how smoking bans have been perceived and how perceptions changes as a function of policy adoption in nearby states. We find that many of the most prominent topics are indeed a function of prior policy adoptions in other states.