Methodology

The PopuList uses an expert-informed qualitative classification approach. Country experts were asked to assess whether parties can be classified as populist, far left, far right and/or euroskeptic on the basis of party documents, public rhetoric, and political behaviour. Final classifications were determined through an iterative process involving expert consultation, internal review, and cross-national consistency checks by the PopuList team.

The PopuList does not measure degrees of populism or extremism. Instead, it provides categorical classifications based on whether parties meet the minimum criteria associated with these concepts.

Party Classification

To classify parties, we employ the method of ‘Expert-Informed Qualitative Comparative Classification’ (EiQCC). We developed this method to classify political parties in a systematic yet context-sensitive way. The approach combines comparative political analysis with the context-based expertise of country specialists. We first establish clear conceptual definitions and coding criteria. We then conduct initial classifications of parties across countries and time periods, drawing on party manifestos, speeches, secondary literature, and other relevant materials. These preliminary classifications are subsequently cross-validated by national experts with detailed contextual knowledge of the parties and countries involved. Disagreements are discussed collectively until consensus is reached.

EiQCC seeks to balance consistency across cases with sensitivity to national political contexts. The approach aims to maximize both conceptual validity and cross-national comparability while acknowledging that party classification inevitably involves interpretive judgment. Coding decisions are continuously reviewed and updated when new information becomes available. For a more detailed discussion of the method, see the accompanying article.

Inclusion Criteria

Parties are included if they have won at least one seat or at least 2 percent of the vote in national parliamentary elections since 1989. Parties voted into office before 1989 that fell below this threshold in subsequent elections have not been examined by the experts.

Consulted Experts

Tarik Abou-Chadi, Koen Abts, Kathrin Ackermann, Alexandre Afonso, Julian Aichholzer, Tjitske Akkerman, Daniele Albertazzi, Andrea, Kai Arzheimer, Paris Aslanidis, Daunis Auers, Ilze Balcere, Tim Bale, Eirikur Bergmann, Laurent Bernhard, Niklas Bolin, Lenka Bustikova, Paul Carls, Filipe Carreira da Silva, Elisabeth Carter, Neil Carter, Matteo Cavallaro, Giorgos Charalambous, Petar Cholakov, Flemming Juul Christiansen, Léonie de Jonge, Neil Dooley, Martin Eiermann, Sarah Engler, Zsolt Enyedi, John Fitzgibbon, Maria Sigridur Finnsdottir, Rob Ford, Eva Gaigalniece, Pietro Castelli Gattinara, Vasiliki Georgiadou, Sergiu Gherghina, Raul Gomez, Matthew Goodwin, Marijana Grbesa, Petra Guasti, Isabelle Guinaudeau, Eelco Harteveld, Mark Harwood, Tim Haughton, Vlastimil Havlik, Reinhard Heinisch, Ivan Hrstic, Carlo Invernizzi-Accetti, Gilles Ivaldi, Kristof Jacobs, Anders Jupskas, Mindaugas Jurkynas, Kirsti M. Jylhä, Petr Kaniok, Andres Kasekamp, Giorgos Katsambekis, Yiannos Katsourides, Elina Kestilä, Alena Kluknavská, Péter Krekó, Algis Krupavicius, Roman Kuhar, Iasonas Lamprianou, Levi Littvay, Luke March, Nonna Mayer, Aleš Michal, Duncan McDonnell, Susi Meret, Thomas Meyer, Michael Minkenberg, Benjamin Moffitt, Aurelien Mondon, Cristian Norocel, Jonathan Olsen, Eoin O’Malley, Mojca Pajnik, Teun Pauwels, Lorenzo Pregliasco, Maria Popova, Paula do Espírito Santo, Bartek Pytlas, Luis Ramiro, Marko Ribač, Lamprini Rori, Saskia Ruth-Lovell, Jens Rydgren, Berto Salaj, Susana Salgado, Antonella Seddone, Allan Sikk, Sorina Soare, Sofia Typaldou, Maria Spirova, Bram Spruyt, Ben Stanley, Yannis Stavrakakis, Dragomir Stoyanov, Paul Sum, Ivan Tranfić, Jogilė Ulinskaitė, Ingrida Unikaitė-Jakuntavičienė, Davide Vampa, Sofia Vasilopoulou, Gerrit Voerman, Christos Vrakopoulos, Markus Wagner, Paul Webb, Annika Werner, Jakub Wondreys, Tuukka Ylä-Anttila, Andrej Zaslove, Ľubomír Zvada, Mattia Zulianello, Ólafur Þórður Harðarson.

Research Assistants

The PopuList would not have been possible without the support of several excellent research assistants who have contributed to the project over the years. Many thanks to Luke Fischer, Hannes Bey, Martin Widdig, and Philipp Mendoza for their hard work and dedication.

References

  • Döring, H., & Manow, P. (2024). ParlGov 2024 Release [Dataset]. Harvard Dataverse.
    https://doi.org/10.7910/DVN/2VZ5ZC
  • Krause, W., Döring, R., Stoppe, J. (2025). PPEG – Political Parties, Presidents, Elections and Governments, Version 2025v1 [Dataset]. WZB Berlin, Harvard Dataverse.
    https://doi.org/10.7910/DVN/5OAH7P
  • March, L. (2012). Radical Left Parties in Europe. London: Routledge.
  • Mudde, C. (2007). Populist Radical Right Parties in Europe. Cambridge: Cambridge University Press.
  • Mudde, C. (2004). The Populist Zeitgeist. Government and Opposition, 39(4), 541–563.
  • Nordsieck, W. (n.d.). Parties and Elections in Europe. Retrieved May 27, 2026, from
    http://www.parties-and-elections.eu/
  • Rooduijn, Matthijs, Andrea L.P. Pirro, Daphne Halikiopoulou, Caterina Froio, Stijn van Kessel, Sarah L. de Lange, Cas Mudde, and Paul Taggart (2023). The PopuList: A Database of Populist, Far-Left, and Far-Right Parties Using Expert-Informed Qualitative Comparative Classification (EiQCC). British Journal of Political Science, 1–10. https://doi.org/10.1017/S0007123423000431
  • Taggart, P., & Szczerbiak, A. (2004). Contemporary Euroscepticism in the party systems of the European Union candidate states of Central and Eastern Europe. European Journal of Political Research, 43(1), 1–27.
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