Ranking algorithms are the information gatekeepers of the Internet era. We develop a stylized framework to study the effects of ranking algorithms on opinion dynamics. We consider rankings that depend on popularity and on personalization. We find that popularity driven rankings can enhance...

Social media are at the center of countless debates on polarization, misinformation, and even the state of democracy in various parts of the world. An essential feature of social media is the ranking algorithm that determines how content is presented to the users. This paper studies the dynamic...

This paper provides a simple theoretical framework to evaluate the effect of key parameters of ranking algorithms, namely popularity and personalization parameters, on measures of platform engagement, misinformation and polarization. The results show that an increase in the weight assigned to...

We provide evidence about voters’ response to crime control policies. We exploit a natural experiment arising from the Italian 2006 collective pardon releasing about one third of the prison population. The pardon created idiosyncratic incentives to recidivate across released individuals and...

We study voters’ response to public policies. We exploit a natural experiment arising from the Italian 2006 collective pardon that created idiosyncratic incentives to recidivate across released individuals and municipalities. We show that municipalities where resident pardoned individuals had...

What is the role of the media in coordinating and mobilizing insurgency against a foreign military occupation? We analyze this question in the context of the Nazi-fascist occupation of Italy during WWII. We study the effect of BBC radio counter-propaganda (Radio Londra) on the intensity of...

In response to the Covid-19 outbreak, among other previous "non-pharmaceutical interven-tions", on March 22, 2020 the Italian Government imposed an economic lockdown and ordered the closing of all non-essential economic activities. This paper estimates the causal effect of this measure on...

Tourism accounts for around one tenth of global GDP. We analyze the impact of entertainment media in drawing tourists to filming locations (media multiplier ) and, in turn, the effect of tourism on local economic development (tourism multiplier ). To assess the media multiplier, we employ a...

How does the internet affect young people’s mental health? We study this question in the context of Italy using administrative data on the universe of cases of mental disorders diagnosed in Italian hospitals between 2001 and 2013, which we combine with information on the availability of...

We investigate the reaction of Italian Members of Parliament to a rigorous fact-checking of their public statements. Our research design relies on a novel randomized field experiment in collaboration with the leading Italian fact-checking company. Our results show that politicians are responsive...