The Effect of Social Media on Elections: Evidence from the United States

Abstract

We study how social media affects election outcomes. We exploit variation in the number of Twitter users across U.S. counties based on early adoption among participants of the 2007 South by Southwest (SXSW) festival—a key event in Twitter's rise to popularity. We show that this variation, which remains predictive of Twitter use a decade later, is unrelated to electoral outcomes before the platform's mass adoption. Our results suggest that exposure to Twitter lowered the Republican vote share in the 2016 presidential election but had limited effects on turnout and vote shares in House and Senate races as well as previous presidential elections. Analyzing two sources of survey data indicates the effects are driven by independent and moderate voters. Our results are consistent with the idea that Twitter's relatively liberal content can persuade voters to alter their views.

Keywords: Social media, Twitter, US Election