Social media platforms are being accused of being at the root of a host of social ills: fake news, depression, political polarization, addiction, and other maladies. To test these assertions, Allcott and his team has been tracking the diffusion of misinformation on social media. Recently, they ran a large-scale randomized experiment in which we paid Facebook users to deactivate their accounts in the four weeks before the 2018 midterm elections. Professor Allcott will present results from these studies and other related work.