Social media platforms ban users and remove posts to moderate their content. This "speech policing" remains controversial because little is known about its consequences and the costs and benefits for different individuals. I conduct two pre-registered field experiments on Twitter to examine the...

Infrastructure and its effects on economic growth, social welfare, and sustainability receive a great deal of attention today. There is widespread agreement that infrastructure is a key dimension of global development and that its impact reaches deep into the broader economy with important and...

Engel and Rogers (1996) find that crossing the US-Canada border can considerably raise relative price volatility and that exchange rate fluctuations explain about one-third of the volatility increase. In re-evaluating the border effect, this study shows that cross-country heterogeneity in price...

This paper uses a gravity framework to investigate the effects of distance as well as subnational and national borders in knowledge spillovers. Drawing on the NBER Patent Citations Database, we examine patent citations data at metropolitan level within the U.S. and the 38 largest patent-cited...

Why do borders still matter for economic activity? The reunification of Germany in 1990 provides a unique natural experiment for examining the effect of political borders on trade both in the cross-section and over time. With the fall of the Berlin Wall and the rapid formation of a political and...

Many studies have found that international borders represent large barriers to trade. But how do international borders compare to domestic border barriers? We investigate international and domestic border barriers in a unified framework. We consider a unique data set of exports from individual...

A large literature on border effects in the wake of McCallum (1995) documents the massive impact of borders on trade. However, all these studies suffer from an identification problem. Border effects are usually identified from cross-sectional variation alone. We do not know how trade would...