Many economic activities are embedded in networks: sets of agents and the (often) rivalrous relationships connecting them to one another. Input sourcing by firms, interbank lending, scientific research, and job search are four examples, among many, of networked economic activities. Motivated by...

Pharmaceutical companies' marketing efforts primarily target physicians, often through individual detailing that entails monetary or in-kind transfers. We study how peer influence broadens these payments' reach beyond the directly paid physicians. Combining Medicare prescriptions and Open...

We study factors influencing individuals' decisions to purchase Citibank stock during the 1920s. Ownership was encouraged by proximity to New York and higher wealth. Lack of familiarity was also an important barrier. The establishment of Citibank branches within a U.S. county or a foreign...

This appendix contains additional figures and tables referenced in the paper, but not included in the main figures and tables. It contains the geographic distribution of shareholders and a visualization of the business network. It includes alternative specifications for the county-level and...

Trade occurs between firms both across borders and within countries, and the vast majority of trade transactions includes at least one large firm with many trading partners. This paper reviews the literature on firm-to-firm connections in trade. A growing body of evidence coming from domestic...

The location of US multinational foreign R&D has shifted significantly to include emerging markets in addition to traditional Western R&D hubs, resulting in two challenges for multinationals: (1) how to transfer knowledge across geographic distances, and (2) how to facilitate learning when local...

We study factors influencing individuals' decisions to purchase Citibank stock during the 1920s. Ownership was encouraged by proximity to New York and higher wealth. Lack of familiarity was also an important barrier. The establishment of Citibank branches within a U.S. county or a foreign...

Networking and the giving and receiving of advice outside of one's own firm are important features of entrepreneurship and innovation. We study how immigrants and natives utilize the potential networking opportunities provided by CIC, formerly known as the Cambridge Innovation Center. CIC is...

This paper quantifies the origins of firm size heterogeneity when firms are interconnected in a production network. Using the universe of buyer-supplier relationships in Belgium, the paper develops a set of stylized facts that motivate a model in which firms buy inputs from upstream suppliers...

Selective contracting is an increasingly popular tool for reducing health care costs, but these savings must be weighed against consumer surplus losses from restricted access. In both public and private prescription drug insurance plans, issuers utilize preferred pharmacy networks to reduce drug...