Domestic politics and the diffusion of international policy innovations: How does accommodation happen?

What happens to policy innovations after they have been adopted? What factors account for subsequent changes to these policies? These are the research questions guiding this study on the spread of and subsequent changes to limit values for nitrogen oxide emissions from large combustion plants. By comparing the processes of diffusion and follow-up policy changes, we assess whether and how policy innovations translate into policy making. In so doing, we build on the literature on the determinants of policy diffusion and transfer. We employ original data on instances of policy adoption and policy change in 24 Organisation for Economic Co-operation and Development (OECD) countries over a period of thirty years (1976-2005). The data are analysed using semi-parametric event-history models. Our empirical findings show that both international and domestic factors account for the observed variation in our data regarding both first-time adoptions and post-adoption modifications. The results reveal that the subsequent tightening of emission standards faces greater obstacles than their mere diffusion (i.e., policy adoption). While international factors and supranational integration appear to impede the subsequent tightening of existing policies, international peer pressure is a strong predictor of an on-going regulatory commitment. Overall, adoption and accommodation processes seem to follow distinctive patterns, suggesting that a promising strategy in policy innovation research would involve differentiation between the first-time adoption and subsequent modification of policies.