The Problem of Interdependence in Subnational Public Policy Comparisons: A Meta-analysis of Mechanisms of Diffusion

The question of interdependence is a crucial problem of the comparative method, which is particularly relevant for the comparison of subnational public policies. The phenomena to be compared, instead of consisting of independent analytical units, are likely to influence each other. This contribution reviews existing approaches to examine interdependent decision making, with special attention for the differences between subnational and international public policies. The empirical literature on policy diffusion will be investigated through a meta-analysis of the “necessary conditions” for different diffusion mechanisms. To this end, a sample of empirical studies is examined with fuzzy-set analysis, and illustrated with some examples.