Fact-checking is the act of checking factual information 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. Fact-checking may be done privately, such as when a magazine editor wants to verify the contents of a news article, either before or after publication. This is called internal fact-checking. Alternatively, the fact-checking analysis may be published, in which case it is called external fact-checking. 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. External post hoc fact-checking organizations first arose in the US in the early 2000s, though the concept first grew in relevance and spread to multiple countries during the 2010s. The US remains the largest market for fact-checking. 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.