“…And how can the conceptual framework of populism be operationalized using valid and reliable empirical evidence? Researchers have used several alternative techniques to classify political parties including (i) identifying “ party families ” according to shared names (Mair and Mudde, 1998); (ii) comparing members of transnational organizational affiliations; (iii) discourse analysis of the rhetorical language used in leadership speeches and social media (Aalberg et al, 2017; Bonikowski and Gidron, 2016; Duina and Carson, 2019; Hart, 2020; Hawkins, 2009; Hawkins et al, 2019a; Kelly, 2019; Kreis, 2017; Lamont et al, 2017); (iv) hand and digitalized content analysis of the texts of programmatic party platforms, exemplified by the Comparative Manifesto Project (CMP) (Budge and Farlie, 1983; Budge et al, 2001; Klingemann et al, 2006; Laver, 2000; Rooduijn and Pauwels, 2011); (v) analysis of roll-call votes by legislators (Poole and Rosenthal, 2001); (vi) surveys of political elites such as elected representatives, parliamentary candidates, activists, and party members (Bailer, 2014; Katz and Wessels, 1999; van Haute and Gauja, 2015); (vii) mass surveys gathering citizen’s estimates of party issue positions and their own policy preferences, as well as measuring populist attitudes (Akkerman et al, 2014), and (viii) using expert surveys to identify party ideological values and issue positions (Bakker et al, 2015; Benoit and Laver, 2006; Castles and Mair, 1984; Meijers and Zaslove, 2020). Reviews suggest that each approach has different pros and cons (Laver, 2001; Mair, 2001; Ware, 1996).…”