Scholars have long been interested in how policies and ideas spread from one observation to another. Yet, the spatial and temporal dynamics of policy diffusion present unique challenges that empirical researchers often neglect. Scholars often use temporally lagged spatial lags (TLSL)—such as the number (or percentage) of prior adopters in a neighborhood—to test various mechanisms of delayed policy diffusion but are largely unaware of two under appreciated issues. First, the effects are not limited to one time period but persist over time by changing the future value of neighboring observations. Second, minor, yet common, choices in model specification—such as omitting spatially correlated and/or autoregressive covariates—can increase the risk of falsely inferring that the outcome is a result of spatial diffusion. Indeed, we offer two applications where small changes to the model specification of an otherwise well‐specified model result in drastically different inferences about policy diffusion. We argue that scholars should avoid haphazardly including TLSLs without considerable theoretical justification, and we conclude on an optimistic note by offering straightforward solutions and new software to address these issues.

Government agencies often encounter problems in service delivery when implementing public programs. This undermines effectiveness and raise questions about accountability. A central component of responsiveness and performance management is that agencies correct course when problems are identified. However, public agencies have an uneven record in responding to problems. In this paper we investigate whether, and to what extent, capacity both within the agency and within institutions performing oversight, improves agency responsiveness to poor performance indicators. Using panel data on eligibility determinations in the Social Security Disability program from U.S. state agencies from 1991-2015 and fixed effects regression, we find that indicators of agency and oversight capacity moderate the relationship between poor performance and improvement. Our results suggest that investments in building capacity not only within agencies, but also within elected institutions, are important for successful policy implementation. However, we find evidence that while agency capacity alone can improve responsiveness to poor performance, the effect of oversight capacity on improving performance requires high agency capacity.

Carolina. His research focuses on administrative oversight and intergovernmental program implementation. Jordan Butcher is an assistant professor of Political Science at Arkansas State University. Her research centers on government institutions and how they influence political careers.