This paper discusses the recent literature on the role of the state in economic development. It concludes that government incentives to enact sound policies are key to economic success. It also discusses the evidence on what happens after episodes of economic and political liberalizations,...

Partly motivated by the recent antitrust investigations concerning Google, we develop a leverage theory of tying in two-sided markets. We analyze incentives for a monopolist to tie its monopolized product with another product in a two-sided market. Tying provides a mechanism to circumvent the...

We consider dynamic competition among platforms in a market with network externalities. A platform that dominated the market in the previous period becomes "focal" in the current period, in that agents play the equilibrium in which they adopt the focal platform whenever such equilibrium exists....

Non-pecuniary incentives motivated by insights from psychology ("nudges") have been shown to be effective tools to change behavior in a variety of fields. An often unanswered question relevant for public policy is whether these promising interventions can be scaled up. In cooperation with a...

Social interactions are considered pivotal to agglomeration economies. We explore a unique dataset on mobile phone calls to examine how distance and population density shape the structure of social interactions. Exploiting an exogenous change in travel times, we show that distance is highly...

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...

We test for the distributional effects of regulation and entry in the mobile telecommunications sector in a highly unequal country, South Africa. Using six waves of a consumer survey of over 134,000 individuals between 2009-2014, we estimate a discrete-choice model allowing for...

In this paper, we use a unique dataset on switching between mobile handsets in a sample of about 8,623 subscribers using tariffs without handset subsidies from a single mobile operator on a monthly basis between July 2011 and December 2014. We estimate a discrete choice model in which we account...

Religious adherence has been hard to study in part because it is hard to measure. We develop a new measure of religious adherence, which is granular in both time and space, using anonymized mobile phone transaction records. After validating the measure with traditional data, we show how it can...

As is now well documented, aid is given for both political as well as economic reasons. The conventional wisdom is that politically-motivated aid is less effective in promoting developmental objectives. We examine the ex-post performance ratings of World Bank projects and generally find that...