B.J.Pol.S. Page 1 of 26 Copyright © Cambridge University Press, 2018. This is an Open Access article, distributed under the terms of the Creative Commons Attribution licence (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted re-use, distribution, and reproduction in any medium, provided the original work is properly cited. doi:10.1017/S0007123418000017 Review Article: A Structured Review of Semi- Presidential Studies: Debates, Results and Missing Pieces JENNY ÅBERG AND THOMAS SEDELIUS* This study maps the general lines of semi-presidential research with regard to theory, topics and methods. It identifies research gaps and provides recommendations for future studies. The review includes a general screen- ing of 327 publications covering the period 1970–2015, and a close reading of sixty-five selected publications. The findings suggest that the inconsistent use of regime type definitions has limited the possibilities for general- izations. The study tracks the influence of some seminal articles, as well as the recent trend of focusing on the role and powers of the president. The article calls for more studies beyond Europe, and suggests that the field would benefit from including Historical and Normative Institutionalism. Finally, it suggests the need for studies on public administration that are relevant to the functioning of semi-presidential government. Keywords: constitutions; democracy; democratization; political institutions; regime type; review; semi-presidentialism. In the wake of the Soviet Union’s collapse, the number of countries with a semi-presidential form of government rose sharply. There are currently more than fifty such countries, spread across Western and Eastern Europe as well as Asia and Africa. 1 Found in many transitional countries and nascent democracies, semi-presidentialism has drawn interest among scholars, particularly in connection to the prospects for democracy’s consolidation and duration. 2 Although the term semi-presidentialism first appeared in the 1970s, its definition is still debated. 3 Consequently, lists of semi-presidential countries have varied considerably between studies. 4 In the late 1990s, Robert Elgie 5 defined semi-presidentialism as a system with a popularly elected president and a prime minister whose government is accountable to a parliament. Based on a series of formal and institutional measures, Elgie’s definition yields a clear-cut sample of semi- presidential countries, and it quickly gained prominence in the field. 6 * School of Education, Health and Social Studies, Dalarna University (emails: jae@du.se; tse@du.se). We wish to thank Cecilia Arensmeier and Erik Hysing and our colleagues at the research seminars in Political Science and Sociology at Dalarna University and Örebro University. At various stages, they provided most valuable feedback on earlier drafts of this article. We are also grateful to the three anonymous reviewers at the British Journal of Political Science. Their comments helped to substantially improve the manuscript during its latter stages. The research was funded by the Swedish Research Council under the granted project ‘Semi-Presidentialism and Governability in Transitional Regimes’, project no. VR 2014-1260. Data replication sets are available at https://dx. doi.org/10.7910/DVN/0OM2WP and online appendices at https://doi.org/10.1017/S0007123418000017. 1 There is also one semi-presidential country in Latin America: Peru. 2 Elgie 1999; Elgie 2015. 3 Duverger introduced the concept in his 1970 book Institutions politiques et Droit constitutionnel [Political Insitutions and Consitutional Law]. 4 Elgie 2004; Elgie 2015. 5 Elgie 1999. 6 Schleiter and Morgan-Jones 2009a.