For any project-related inquiries, please write an e-mail to


This page lists the project publications as well as selected other publications making use of the EUPLEX dataset.

Project publications

Hurka, S., Haag, M. and Kaplaner, C. (2021) Policy complexity in the European Union, 1993-today: introducing the EUPLEX dataset. Journal of European Public Policy.
doi: 10.1080/13501763.2021.1938174 PDFReplication material (.zip) Dataset

Abstract: Despite its importance for the sustainability of democratic governance, policy complexity is still an understudied phenomenon. What makes policies complex? Why are some policies more complex than others? And what are the consequences of this complexity for the political, economic and societal level? These questions still lack answers, which is both due to a lack of conceptual clarity and a lack of suitable data. In order to tackle these challenges, we introduce the EUPLEX dataset, comprising information on the complexity of more than 6,000 policy proposals adopted by the European Commission between 1993 and today. Relying on automated methods of data collection and natural language processing, EUPLEX allows us to compare the complexity of Commission proposals over time, across policy domains, and institutional and political configurations. The dataset will be updated continuously in the future as new policy proposals become available and is available free-of-charge to the research community.

Adam, C., Hurka, S., Knill, C. and Steinebach, Y. (2021) On democratic intelligence and failure: The vice and virtue of incrementalism under political fragmentation and policy accumulation. Governance.
doi: 10.1111/gove.12595

Abstract: The vice and virtue of incrementalism have been the subject of a long‐standing academic debate. This debate, however, lacks a dynamic perspective that analyzes how the transformation of politics—mainly in the form of increasing levels of political fragmentation within decision‐making arenas and increasing complexity of policy‐mixes—affects the role of incrementalism. We argue that both of these trends make the virtues of incrementalism politically even more valuable than they have always been. At the same time, this proliferation of incrementalism comes at the costs of overlooked second‐order effects. Since the empirical reality of incrementalism is primarily one that results in incremental policy accumulation, it continuously adds implementation burdens, enhances the demandingness of substantive policy debate, and makes effective science communication more difficult. Thereby, accumulative incrementalism becomes one source of pressure on three cornerstones of legitimate governance: effective policy implementation, sophisticated policy debate, and evidence‐based policymaking.

Hurka, S. and Steinebach, Y. (2020) Legal Instrument Choice in the European Union. Journal of Common Market Studies.
doi: 10.1111/jcms.13068 PDF

Abstract: Regulations and directives are the central legal instruments used by the EU. In some instances, the Commission is not legally required to choose a specific legal instrument, but can make this decision autonomously. However, we know surprisingly little about the factors that influence this decision. Based on an original dataset of all directives and regulations proposed by the European Commission in ordinary legislative procedures between 2009 and 2018, we find that the choice of a legal instrument is strongly determined by prior policy decisions and varies systematically across policy areas depending on the extent to which they have traditionally been addressed under the co‐decision procedure. In addition, we find that the Commission's use of regulations increases under conditions of increased euroscepticism, indicating that instead of granting dissenting member states more room to manoeuvre, the Commission prefers to keep them on a short leash.

Hurka, S. and Haag, M. (2020) Policy complexity and legislative duration in the European Union. European Union Politics, 21(1), 87–108.
doi: 10.1177/1465116519859431 PDFReplication material (.zip) LSE EUROPP article

Abstract: This article investigates the impact of policy complexity on the duration of legislative negotiations in the European Union employing survival analysis. We conceptualize policy complexity as a three-dimensional construct encompassing structural, linguistic and relational components. Building on this conceptual framework, we measure the complexity of 889 Commission proposals published under the ordinary legislative procedure between 2009 and 2018. Controlling for institutional and political drivers of legislative duration identified by previous studies, we show that different types of policy complexity influence the duration of the decision-making process in the European Union to varying degrees, at different points in time and partially in unexpected ways. On a general level, our study highlights that developing a better understanding of the origins and consequences of policy complexity in the European Union is a key task for scholars of European integration.