Classifying parties as populist Although experts generally agree that populist political leaders or parties display high levels of anti-elitism, definitions of populism vary. We use three measures to classify parties as populist: anti-elite ratings from the 2024 Chapel Hill Expert Survey (CHES), the 2023 Populism and Political Parties Expert Survey (POPPA) and the 2023 PopuList . We define a party as populist when at least two of these three measures classify it as such. CHES, which was conducted from October to December 2024, asked 609 political scientists specializing in political parties and European integration to evaluate the 2024 positions of 279 European political parties across all European Union member states, except for Luxembourg. The survey also gathered their views of parties in Iceland, Norway, Switzerland, Turkey and the United Kingdom.…