The Diffusion of Impact Assessment Practices in Europe

The diffusion of the use of various forms of impact assessments (IAs) in different political settings and legal traditions illustrates the great malleability of the tool. This diversity is not only reflected in the adoption of different models of IA across the various jurisdictions examined, but also in the way this practice is effectively implemented. Factors explaining the various types of IA implemented in various European jurisdictions include the patterns of diffusion from one country to another, the interaction of politics with expert knowledge and the prevailing “evidence eco-system” in each jurisdiction. In this study we explore diffusion patterns, not only in terms of the adoption of the tool of IA, but also in terms of the specific types of IA implemented. We do so by introducing a taxonomy developed with the purpose to describe the interaction of politics and expertise in each jurisdiction. The last part of the chapter empirically connects the diffusion process with the type of IA prevalent in a jurisdiction