Appendix B: Classifying European political parties

European political parties can be classified as populist using a three-measure consensus drawn from expert surveys, according to a new Pew Research Center methodology. The approach combines data from the 2024 Chapel Hill Expert Survey, the 2023 POPPA survey, and the PopuList 3.0 project to identify anti-elite parties across the continent [1]. The classification defines a party as populist when at least two of the three measures agree [1]. The 2024 Chapel Hill Expert Survey (CHES) polled 609 political scientists on the positions of 279 parties across all European Union member states except Luxembourg, plus Iceland, Norway, Switzerland, Turkey, and the United Kingdom [1]. CHES measures anti-elitism by averaging two variables: support for direct over representative democracy and the salience of anti-establishment rhetoric. Parties scoring 7.0 or higher on this average are considered populist [1]. The 2023 Populism and Political Parties Expert Survey (POPPA) asked 324 experts to rate 312 parties in 31 European countries [1]. Its populism measure averages five indicators, including the extent to which a party views politics as a moral struggle between good and evil and the degree to which it centers ordinary people against elites. A score of 7.0 or above on this composite index also flags a party as populist [1]. The third pillar, PopuList 3.0, relies on comparative and country experts to classify parties as populist, far right, or far left based on core ideological attributes. It considers parties that have won at least one seat or 2% of a national parliamentary election since 1989 [1]. The project is part of a broader landscape of democracy indices that quantitatively assess political systems, enabling researchers to study regime transformation processes through categorical or continuous measurements [3]. Beyond populism, the methodology sorts parties into left, right, or center using ideological scales. CHES uses the variable “LRGEN,” where 0 is extreme left and 10 is extreme right; parties below 4.5 are left, above 5.5 are right, and those in between are center [1]. POPPA confirms these ratings with its “LROVERALL” variable on the same 0-to-10 scale, achieving 100% agreement on the parties classified as populist [1]. Europe, a continent of about fifty sovereign states and roughly 745 million people as of 2021, has seen its political landscape shaped by centuries of ideological evolution, from the Enlightenment and industrial revolution to the Cold War division and subsequent integration [2]. The new classification framework arrives as right-wing populism has reshaped party identities elsewhere, including the United States, where the Republican Party has shifted toward populist and neo-nationalist positions since 2016 [4].