YouTube’s stricter policies against election misinformation was followed by sharp drops in the prevalence of false and misleading videos on Facebook and Twitter, according to new research released Thursday, underscoring the video service’s power across social media.

Researchers at the Center for Social Media and Politics at New York University found a significant rise in election fraud YouTube videos shared on Twitter immediately after the Nov. 3 election. In November, those videos consistently accounted for about one-third of all election-related video shares on Twitter. The top YouTube channels about election fraud that were shared on Twitter that month came from sources that had promoted election misinformation in the past, such as Project Veritas, Right Side Broadcasting Network and One America News Network.

But the proportion of election fraud claims shared on Twitter dropped sharply after Dec. 8. That was the day that YouTube said it would remove videos that promoted the unfounded theory that widespread errors and fraud changed the outcome of the presidential election. By Dec. 21, the proportion of election fraud content from YouTube that was shared on Twitter had dropped below 20% for the first time since the election.