Is there convergence in convergence research? an overview of empirical studies on policy convergence

Abstract In this review, we portray findings and conceptualizations of selected empirical studies on policy convergence and related concepts. The article reveals that there is no homogenous picture of policy convergence: Although frequently observed, empirical studies often disagree as to its extent. The representation of policy fields, geographical regions and periods analysed differ, which makes an overall assessment of policy convergence impossible. The comparability is further constrained by differences in the operationalization and research methods applied by scholars in this field. Whereas many studies concentrate on the analysis of causal factors for policy convergence, we argue that the degree and level of convergence also deserve attention. Keywords: Comparative politicsconceptualizationempirical researchpolicy convergencepolicy diffusionpolicy transfer Acknowledgements The authors would like to thank Christoph Knill, Kerstin Tews and Helge Jörgens for helpful comments, insights and assistance relating to this article. However, the authors alone are responsible for the arguments made and for any errors or omissions contained herein. Michael Dobbins, Jale Oenel and Natascha Warta deserve credit for assistance in general and language editing. Notes 1. By related concepts of policy convergence, we mean policy diffusion, policy transfer, policy learning and isomorphism (see Knill Citation2005). 2. We applied an encompassing search procedure using several bibliographical databases, including the SSCI. We also checked the literature quoted in other studies (especially reviews). Thereby we ended up with about 450 studies of general interest (not only empirical research) which we scrutinized in more detail. Key words for searching were ‘policy convergence’, ‘policy divergence’, ‘policy diffusion’, ‘policy transfer’, ‘policy learning’, ‘lesson drawing’ and ‘isomorphism’. Empirical studies which address policy convergence issues but cannot be found with those key words, i.e. those in comparative politics in general dealing with the topic, might have been overlooked. Research published up to the middle of 2004 was considered. 3. Hence, we selected only literature dealing with policies at the national level. 4. We are aware that this phenomenon (large versus small-n studies) differentiates qualitative and quantitative literature; however, we treat these studies as comparable while bearing in mind their respective advantages and disadvantages. 5. See Holzinger and Knill Citation(2005) for the concept of the level of convergence. 6. See, for example, Tews et al. (Citation2003: 574) who define ‘regulatory’ and ‘ideational’ competition as the two main international driving mechanisms for convergence. 7. See Holzinger and Knill (Citation2005 ) for the concept of the degree of convergence. 8. The concept we introduce here was already applied by Howlett (Citation2000: 306, 309) and named ‘strong convergence’. However, Howlett refers to Unger and van Waarden Citation(1995) as a source for this term although those authors mean something different, namely the approximation of two countries' policies towards each other, not towards another policy (model) (Unger and van Waarden Citation1995: 3).