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...

Tech clusters like Silicon Valley play a central role for modern innovation, business competitiveness, and economic performance. This paper reviews what constitutes a tech cluster, how they function internally, and the degree to which policy makers can purposefully foster them. We describe the...

We study the relationship between ethnicity, occupational choice, and entrepreneurship. Immigrant groups in the United States cluster in specific business sectors. For example, Koreans are 34 times more concentrated in self employment for dry cleaning than other immigrant groups, and...

This research explores social networks and their relationship to access to health care among adult Mexican-Americans. We use data from the Medical Expenditure Panel Survey (MEPS) linked to data from the 2000 U.S. Census and other data sources. We analyze multiple measures of access to health...

We explore the links between social capital and labor market networks at the neighborhood level. We harness rich data taken from multiple sources, including matched employer-employee data with which we measure the strength of labor market networks, data on behavior such as voting patterns that...

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...

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...