Bias in Fact Checking?: An Analysis of Partisan Trends Using PolitiFact Data

Fact checking is one of many tools that journalists use to combat the spread of fake news in American politics. Like much of the mainstream media, fact checkers have been criticized as having a left-wing bias. The efficacy of fact checking as a tool for promoting honesty in public discourse is dependent upon the American public’s belief that fact checkers are in fact objective arbiters. In this way, discovering whether this partisan bias is real or simply perceived is essential to directing how fact checkers, and perhaps the mainstream media at large, can work to regain the trust of many on the right. This paper uses data from PolitiFact, one of the most prominent fact checking websites, to analyze whether or not this bias exists. Prior research has shown that there is a selection bias toward fact checking Republicans more often and that they on average receive worse ratings. However, few have examined whether this differential treatment can be attributed to partisan bias. While it is not readily apparent how partisan bias can be objectively measured, this paper develops and tests some novel strategies that seek to answer this question. I find that among PolitiFact’s most prolific fact checkers there is a heterogeneity in their relative ratings of Democrats and Republicans that may suggest the presence of partisanship.