Any label or text directly pointing out that content is potentially false based on fact-checker assessments

Reduce belief in and willingness to spread misleading or false content.

Across a number of survey experiment studies, researchers find mixed evidence that labeling misleading content with warnings based on professional fact-checkers' evaluations - for example “Disputed,” “Rated false,” or “False information checked by independent fact-checkers” - can reduce participants' willingness to share misinformation. Labels should also be used carefully as several studies suggest they have potential to backfire.

In one survey experiment, Mena (2020) found subjects were less likely to say they would share false news stories when they were labeled “Disputed by Snopes.com and PolitiFact”. (Note: All effects we include are statistically significant, unless otherwise stated.) Koch et al. (2023) likewise observed that embedding fact-check labels in a survey experiment reduced participants’ intentions of amplying (sharing or liking) flagged content. And Martel & Rand (2023) saw the same pattern in their analysis of 11 survey experiments conducted by their research lab; participants were less likely to say they would share stories that were labeled "False Information. Checked by independent fact-checkers". In a final experiment conducted on Facebook Messenger, however, Offer-Westort et al. (2023) observed no discernable effects of fact-checking labels on subjects' willingness to share false news posts either privately on Messenger or publicly on their Facebook feeds, whereas the researchers did by comparison see significant positive effects of "accuracy nudges". This final study was conducted in both a more ecologically valid setting and with users from the Global South (Nigeria and Kenya), and so calls into question the generalizability of the studies above.

There may be several other limitations to using fact-checking labels. One is the so-called implied truth effect: the presence of warnings on some news headlines implies to some participants that unlabeled content is more likely to be true (Pennycook et al., 2020). In contrast to the implied truth effect, other research suggests that because false news is extremely rare compared to true news, the presence of warnings may actually have the opposite effect, namely increasing general skepticism about all news (Hoes et al., 2023; van der Meer et al., 2023). Taken together, evidence suggests that labels may have negative indirect effects on unlabeled content, but that these effects may depend on the prevalence of false content.

In sum, there is mixed evidence of the effectiveness of fact-checking labels on reducing the spread of misinformation.  Labels may also have the undesirable indirect effect that, depending on the prevalence of fake news, they either increase the credibility of potentially false but unlabeled content (implied truth effect) or increase general skepticism toward all news.

Since social media users often do not investigate the truth of headlines and claims they see in their feeds, it is helpful to provide users with additional information to reduce the likelihood they will spread false news.

In this review we focus on the effectiveness of fact-checking labels on reducing the spread of misinformation and find mixed evidence. While not discussed here, there may however be evidence that labels reduce belief in false news (Clayton et al., 2020; Gaozhao, 2021, Porter & Wood, 2022).