RPC-Lex: A dictionary to measure German right-wing populist conspiracy discourse online.

We describe a novel computational dictionary for the study of right-wing populist conspiracy discourse (RPC) on the internet, specifically in the context of contemporary German politics. After first presenting our definition of conspiracy discourse and grounding it in antecedent research on mediated rhetoric at the intersection of right-wing populism and conspiracy theory, we proceed by outlining our approach to dictionary construction, relying on a combination of manual and automated methods. We validate our dictionary via parallel manual coding of 2,500 sentences using the categories contained in the dictionary as labels and compare the consensus result with the label assigned to each sentence by the dictionary, achieving satisfactory results. We then test our approach on two different datasets composed of alternative news articles and Facebook comments that spread conspiracy theories. Finally, we summarize our observations both on the methodological premises of the approach and on the object of populist right-wing conspiracy discourse and its dynamics more broadly. We close with an outlook on the potentials and limitations of the dictionary-based approach and future directions in applications of content analysis to the study of conspiracy discourse.