Digitization has led to product proliferation, straining traditional institutions for product discovery; but digitization has also spawned crowd-based rating systems. We compare the relative impacts of professional critics and crowd-based Amazon star ratings on consumer welfare in book...

We examine the effect of consumer reviews on relative sales of books on Amazon.com and BarnesandNoble.com. We find that 1) reviews are overwhelmingly positive at both sites, but there are more reviews and longer reviews at Amazon.com, 2) an improvement in a book's reviews leads to an increase in...

This paper studies the economic effects of endorsements. In the publishing sector, endorsements from the Oprah Winfrey Book Club are found to be a business stealing form of advertising that raises title level sales without increasing the market size. The endorsements decrease aggregate adult...

Online reviews are a powerful means of propagating the reputations of products, services, and even employers. However, existing research suggests that online reviews often suffer from selection bias--people with extreme opinions are more motivated to share them than people with moderate...

We investigate the informativeness of hygiene signals in online reviews, and their effect on consumer choice and restaurant hygiene. We first extract signals of hygiene from Yelp. Among all dimensions that regulators monitor through mandated restaurant inspections, we find that reviews are more...

We study the nature of peer effects in the market for new cell phones. Our analysis builds on de-identified data from Facebook that combine information on social networks with information on users' cell phone models. To identify peer effects, we use variation in friends' new phone acquisitions...

Social media data presents challenges for forecasters since one must convert text into data and deal with issues related to these measures being collected at different frequencies and volumes than traditional financial data. In this paper, we use a deep learning algorithm to measure sentiment...

Because consumer reviews leverage the wisdom of the crowd, the way in which they are aggregated is a central decision faced by platforms. We explore this "rating aggregation problem" and offer a structural approach to solving it, allowing for (1) reviewers to vary in stringency and accuracy, (2)...

How should policymakers disseminate information: by broadcasting it widely (e.g., via mass media), or letting word spread from a small number of initially informed "seed" individuals? While conventional wisdom suggests delivering information more widely is better, we show theoretically and...

We study the causal effect of social media on ethnic hate crimes and xenophobic attitudes in Russia using quasi-exogenous variation in social media penetration across cities. Higher penetration of social media led to more ethnic hate crimes, but only in cities with a high pre-existing level of...