Online sources sometimes publish information that is false or intentionally misleading. We study the role of social networks and advertising on social networks in the dissemination of false news stories about childhood vaccines. We document that anti-vaccine Facebook groups disseminate false...

COVID-19 vaccines are widely available in wealthy countries, yet many people remain unvaccinated. Understanding the effectiveness -- or lack thereof -- of popular vaccination campaign strategies is therefore critical. In this paper, we report results from two studies that tested strategies...

Much debate exists around the impact that illegal file sharing may have on the creative industries. Similarly, opinions differ regarding whether the producers of artistic works should be forced to accept any weakening of intellectual property rights resulting from illegal file sharing, or if...

A bona fide currency functions as a medium of exchange, a store of value, and a unit of account, but bitcoin largely fails to satisfy these criteria. Bitcoin has achieved only scant consumer transaction volume, with an average well below one daily transaction for the few merchants who accept it....

We use aggregated data from Facebook to show that COVID-19 was more likely to spread between regions with stronger social network connections. Areas with more social ties to two early COVID-19 “hotspots” (Westchester County, NY, in the U.S. and Lodi province in Italy) generally had more...

We introduce a new measure of social connectedness between U.S. county-pairs, as well as between U.S. counties and foreign countries. Our measure, which we call the "Social Connectedness Index" (SCI), is based on the number of friendship links on Facebook, the world's largest online social...

We use 633 days of tweets about the Euro/dollar exchange rate to determine their information content and the profitability of trading based on Twitter Sentiment. We develop a detailed lexicon used by FX traders to translate verbal tweets into positive, negative and neutral opinions. The...

Developing country lenders are taking advantage of fintech tools to create fully digital loans on mobile phones. Using administrative and survey data, we study the take up and impacts of one of the most popular digital loan products in the world, M-Shwari in Kenya. While 34% of those eligible...

The rise of social media has provoked both optimism about potential societal benefits and concern about harms such as addiction, depression, and political polarization. In a randomized experiment, we find that deactivating Facebook for the four weeks before the 2018 US midterm election (i)...