INTRODUCTION

As has been shown in the previous chapter, the study of cross‐national policy convergence is a highly popular research area in political science. Notwithstanding these far‐reaching research efforts, it is generally acknowledged that we still have a limited understanding of the causes and conditions of policy convergence.

It is the objective of this chapter to develop the theory further by a systematic discussion of the causal factors of policy convergence and by the formulation of general theoretical expectations on policy convergence for each factor. We proceed in the following steps. First, we briefly present the central aspects we distinguish for the assessment of policy convergence. In a second step, we identify and compare different causal factors of cross‐national policy convergence. Having elaborated on the major causes of policy convergence, however, we still know little about the conditions under which these factors actually lead to convergence. This is the objective of the third part of our analysis, in which we develop theoretical expectations for the different aspects of cross‐national policy convergence. These hypotheses form the background for the empirical study of environmental policy convergence in Europe presented in the following chapters. Specifications of these expectations in the form of testable hypotheses that relate to the different empirical models used in this study will be presented in the respective chapters (6 and 7).

HOW TO CONCEPTUALISE POLICY CONVERGENCE?

For the purpose of the underlying study, we define policy convergence