Who Are Your Neighbors? The Role of Ideology and Decline of Geographic Proximity in the Diffusion of Policy Innovations

Abstract

States adopt policy innovations within the confines of a dynamic American federal system, but our study of policy diffusion tends to be fairly static. Single-policy studies incorporate temporal variation, but for only one innovation. Macro-level analyses examine broad patterns, but often by completely pooling across policy and time. This makes it difficult to identify how diffusion patterns change over time, though Walker's early work explicitly identified such temporal instability. This study specifically examines how neighbor and ideological cues change in importance over time using a dataset of 556 policies adopted from 1960 to 2014. While the findings demonstrate the generality of many key internal, external, and policy-level determinants of adoption, there is variation in these effects across time. Most important is the relative stability of ideological similarity between adopters and declining influence of contiguous neighbors. Further, political polarization plays a role in conditioning neighbor and ideological cues.

Policy Diffusion Results: A New Database for Systematic Review and Meta-Analysis

“…The true role of legislative professionalism, however, remains unclear in diffusion research. Large pooled event history models have found negative effects (Boehmke and Skinner 2012; Mallinson 2020b) or no effect (Mallinson 2019). Taken together, the above makes legislative professionalism a useful and interesting example of the meta-analysis capabilities of the PDR database.…”

Clarifying the Measurement of Relative Ideology in Policy Diffusion Research

“…Doing so effectively sets the origin of the measure at zero. The Online Appendix addresses another proposed approach (Hannah and Mallinson 2018; Mallinson 2019).…”

“…These are lessons that lawmakers draw from past adopting states regarding the political success of the policy, particularly from states that have a similar general ideological makeup. Subsequent evidence suggests that learning from ideological “neighbors” is just as important as learning from contiguous ones (Desmarais, Harden, and Boehmke 2015) and has become more important to the states over time (Mallinson 2019). Accurately understanding the role of ideology in shaping state innovation has both theoretical and substantive importance, particularly in an era of national gridlock where so much policy activity is occurring not in the federal government but in the states.…”

“…But there are variations in how this is applied in subsequent research. Though nearly as many papers use the alternative citizen ideology (Boushey 2016; Bradford and Bradford 2017; Bromley-Trujillo et al 2016; Hannah and Mallinson 2018; Mallinson 2019; Seljan and Weller 2011), Karch and Cravens (2014) use “policy mood” from Enns and Koch (2013), and Finger (2018) uses a measure of policy liberalism from Caughey and Warshaw (2016), as opposed to government or citizen liberalism.…”

“… 2. Few articles that use the measure discuss what was done for the first year (see Mallinson 2019; Hannah and Mallinson 2018; Cruz-Aceves 2018 for exceptions). …”