Measuring Populism in Political Parties: Appraisal of a New Approach

Populism has become a pervasive concept in political science research. However, a central and basic question remains unanswered: which European parties are more populist than others? Despite the increasing wealth of studies on populism in parties, we lack data that measures populism in political parties in a valid and precise manner, that recognizes that populism is constituted by multiple dimensions, and that ensures full coverage of all parties in Europe. In this article, we first appraise the weaknesses of existing approaches. Arguing that parties' populism should be measured as a latent construct, we then advocate a new approach to operationalizing and measuring populism in political parties using expert surveys. Relying on the Populism and Political Parties Expert Survey spanning 250 political parties in 28 European countries, we show that populism is best measured in a multi-dimensional and continuous manner. We subsequently illustrate the advantages of our approach for empirical analysis in political science.