Fact-checker

Fact checking is the act of checking factual assertions in non-fictional text in order to determine the veracity and correctness of the factual statements in the text. This may be done either before (ante hoc) or after (post hoc) the text has been published or otherwise disseminated.

Ante hoc fact-checking (fact checking before dissemination) aims to remove errors and allow text to proceed to dissemination (or to rejection if it fails confirmations or other criteria). Post hoc fact-checking is most often followed by a written report of inaccuracies, sometimes with a visual metric from the checking organization (e.g., Pinocchios from The Washington Post Fact Checker, or TRUTH-O-METER ratings from PolitiFact). Several organizations are devoted to post hoc fact-checking, such as FactCheck.org and PolitiFact.

Research on the impact of fact-checking is relatively recent but the existing research suggests that fact-checking does indeed correct misperceptions among citizens, as well as discourage politicians from spreading misinformation.

One study finds that fact-checkers PolitiFact, FactCheck.org, and Washington Post's Fact Checker overwhelmingly agree on their evaluations of claims.

However, a study by Morgan Marietta, David C. Barker and Todd Bowser found "substantial differences in the questions asked and the answers offered." They concluded that this limited the "usefulness of fact-checking for citizens trying to decide which version of disputed realities to believe."

A paper by Chloe Lim, Ph.D. student at Stanford University, finds little overlap in the statements that fact-checkers check. Out of 1065 fact-checks by PolitiFact and 240 fact-checks by The Washington Post's Fact-Checker, there were only 70 statements that both fact-checkers checked. The study found that the fact-checkers gave consistent ratings for 56 out of 70 statements, which means that one out every five times, the two fact-checkers disagree on the accuracy of statements.

Studies of post hoc fact checking have made clear that such efforts often result in changes in the behavior, in general, of both the speaker (making them more careful in their pronouncements) and of the listener or reader (making them more discerning with regard to the factual accuracy of content); observations include the propensities of audiences to be completely unswayed by corrections to errors regarding the most divisive subjects, or the tendency to be more greatly persuaded by corrections of negative reporting (e.g., "attack ads"), and to see minds changed only when the individual in error was someone reasonably like-minded to begin with.

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