Both Judge and Party? Investigating the Political Unbiasedness of Fact-checkers

This paper provides the first statistical study of political differences between fact-checkers. I collect a comprehensive dataset of articles published by the six main general-interest French fact-checkers up until July 2021 and identify the political orientations of entities that are fact-checked. French fact-checkers commit to non-partisanship. However, they are affiliated with a media outlet. I find differences in fact-checkers' political content, which reflect the media outlets' slant. This implies that fact-checkers are not politically neutral. In particular, they are less likely to fact-check ideologically aligned entities; when they do, they are more likely to select statements that they assess as correct. Moreover, fact-checkers with connections to the government fact-check the incumbent party less often. Finally, political differences increase before elections. Replicating the analysis for U.S. fact-checkers to test the external validity yields similar results.