Facebook Ad Policy Slashes “Fake News” Sharing by 75%, MIT Study Finds

Advertising revenue may power social media platforms, but it’s also fueling the spread of misinformation that threatens their business models and could trigger new regulatory measures, according to new research from MIT Sloan.

A study by MIT economist Catherine Tucker and Occidental College’s Lesley Chiou found a dramatic 75 percent reduction in fake news sharing on Facebook after the platform implemented a new advertising system designed to intercept false or misleading content.

The findings come at a critical time for social media companies. Facebook’s platform was allegedly used by Russian operatives attempting to influence the 2016 U.S. presidential election through propaganda campaigns, according to a February 2018 indictment from the U.S. Justice Department. These operatives reportedly created easily shareable content and then leveraged Facebook’s marketing tools to target users with strong opinions on polarizing issues.

To isolate the effectiveness of Facebook’s ad policy changes, the researchers examined how anti-vaccination misinformation spread on social media. They selected this topic because it was less likely to be affected by election news cycles, allowing for clearer measurement of the ban’s impact.

“A small fraction of authors account for a large majority of posts, which reinforces the concern that social media allows an individual to reach a wide audience and share information without editorial or fact-checking input,” the study noted.

The researchers discovered that Facebook groups facilitate the spread of misinformation through two primary mechanisms: they function as “echo chambers” where members reinforce each other’s views through likes and comments, and they serve as distribution channels when members share posts from the group to their broader networks.

After collecting data on anti-vaccination articles published to Facebook before and after the November 2016 advertising restrictions, the researchers compared the findings with Twitter, which made no changes to its ad policies during the same period. The contrast was stark—Facebook saw a 75 percent decrease in false content sharing compared to pre-ban levels.

“Our results suggest that advertising has a large influence on the spread of false news on social media,” the researchers concluded. “Approximately 75 percent of the popularity of fake news may be attributed to advertising. The policy measure of banning advertising of fake news presents an effective way of mediating the popularity of false information online.”

The study suggests that platforms could fight misinformation using the very advertising systems that helped propagate it. The researchers propose that negative advertising promoting false information could be counterbalanced by positive advertising designed to disseminate accurate information. However, Tucker noted that such an approach requires human judgment and is difficult to implement at scale.

The findings highlight the complex relationship between advertising practices and information quality on social platforms. While Facebook’s ad policy changes demonstrated effectiveness in reducing misinformation, the researchers cautioned that a comprehensive solution would need to address organic user sharing as well.

“The actions of platforms such as Facebook in regulating advertising do seem to have had an effect on the volume of fake news,” Tucker said. “However, our paper also emphasizes that in just focusing on ads and fake news, we are missing the bigger picture, which is the organic spread of misinformation by users themselves.”

This raises significant free speech considerations. “The popularity of fake news may occur in the absence of advertising, as users share articles with others in their social network,” Tucker added, “but working to stamp out misinformation in those posts runs into its own set of problems. Trying to regulate that seems to get us into very problematic First Amendment territory.”

As social media platforms continue grappling with their role in information distribution, this research suggests that advertising policy adjustments offer a promising but partial solution to the complex challenge of combating misinformation online.