This paper considers a long-term relationship between two agents who both undertake a costly action or investment that together produces a joint benefit. Agents have an opportunity to expropriate some of the joint benefit for their own use. Two cases are considered: (i) where agents are risk...

I provide a typology of social capital, breaking it down into seven more fundamental forms of capital: information capital, brokerage capital, coordination and leadership capital, bridging capital, favor capital, reputation capital, and community capital. I discuss how most of these forms of...

We study how the introduction of microfinance changes the networks of interactions among 16476 households in 75 Indian villages, and develop a new dynamic model of network formation to explain the empirical findings. None of the villages were exposed to microfinance by 2006, and 43 villages were...

A critical element of word of mouth (WOM) or buzz marketing is to identify seeds, often central actors with high degree in the social network. Seed identification typically requires data on the full network structure, which is often unavailable. We therefore examine the impact of WOM seeding...

I discuss economic and social sources of inequality and elaborate on the role of social networks in inequality, economic immobility, and economic inefficiencies. The lens of social networks clarifies how the entanglement of people's information, opportunities, and behaviors with those of their...

We study the consequences of job markets' heavy reliance on referrals. Referrals screen candidates and lead to better matches and increased productivity, but disadvantage job-seekers who have few or no connections to employed workers, leading to increased inequality. Coupled with homophily,...

We show that prominent centrality measures in network analysis are all based on additively separable and linear treatments of statistics that capture a node's position in the network. This enables us to provide a taxonomy of centrality measures that distills them to varying on two dimensions:...

Can we identify the members of a community who are best- placed to diffuse information simply by asking a random sample of individuals? We show that boundedly-rational individuals can, simply by tracking sources of gossip, identify those who are most central in a network according to "diffusion...

We examine how participation in a microfinance program diffuses through social networks. We collected detailed demographic and social network data in 43 villages in South India before microfinance was introduced in those villages and then tracked eventual participation. We exploit exogenous...

When people coordinate their behaviors with their friends---choosing whether to adopt a new technology, to protest against a government, to attend university, etc.---divisions within a social network can result in people adopting different conventions of behavior in different parts of the...