We survey the empirical literature in economics on the impact of media technologies on
social capital. Guided by a simple model of information and collective action, we cover a …

What role does propaganda play in the information politics of authoritarian societies, and
what is its relationship to censorship? What have we learned from rival accounts in recent …

This paper investigates the link between social media and hate crime. We show that
antirefugee sentiment on Facebook predicts crimes against refugees in otherwise similar …

We study how social media affects election outcomes in the United States. We use variation
in the number of Twitter users across counties induced by early adopters at the 2007 South …

How effective is fact checking in countervailing “alternative facts,” ie, misleading statements
by politicians? In a randomized online experiment during the 2017 French presidential …

This paper studies information diffusion in social media and the potential role of bots in
influencing public opinions. Using Twitter data on the 2016 EU Referendum (“Brexit”) and …

We study whether social media can amplify antiminority sentiment with a focus on Donald
Trump's political rise. Using an instrumental variable strategy based on Twitter's early …

In this paper, we document basic facts regarding public debates about controversial political
issues on Chinese social media. Our documentation is based on a dataset of 13.2 billion …

Can external threats strengthen group identity? A growing body of research in economics
emphasises the importance of cultural attributes such as identity for trust and cooperation …

We develop new tools for estimating the causal effects of treatments or instruments that
combine multiple sources of variation according to a known formula. Examples include …