How the Enlargement Affects European Union Legislative Process

This article contributes to the ongoing debate regarding the systemic impact of EU enlargements on the duration of the legislative process. Two methods, interrupted time series analysis and survival analysis (the Cox model), are used to show the effects of enlargements, using empirical data comprising EU secondary law directives and regulations. A key distinction of this study from most similar research lies in its focus on distinguishing between legislative and implementing acts, which mitigates the risk of conflating the analysis due to substantial differences in their adoption processes. The methodology and research design help us disentangle the enlargement effects from those of the Treaty reforms and other institutional and structural parameters of the EU decisionmaking process. The findings reveal a significant acceleration of the legislative process at the moment of the 2004 enlargement, essentially confirming our prior research results. The validity of our conclusions is substantially enhanced by the improvements in modeling techniques. The article also explores potential reasons for the acceleration of the legislative process and concludes that the most likely cause is the refinement of working methods in the Council.