We examine friendships and study partnerships among university students over several years. At the aggregate level, connections increase over time, but homophily on gender and ethnicity is relatively constant across time, university residences, and different network layers. At the individual...

We show that supply networks are inefficiently, and insufficiently, resilient. Upstream firms can expand their production capacity to hedge against supply and demand shocks. But the social benefits of such investments are not internalized due to market power and market incompleteness. Upstream...

Network diffusion models are used to study things like disease transmission, information spread, and technology adoption. However, small amounts of mismeasurement are extremely likely in the networks constructed to operationalize these models. We show that estimates of diffusions are highly...

To understand new information, we exchange models or interpretations with others. This paper provides a framework for thinking about such social exchanges of models. The key assumption is that people adopt the interpretation in their network that best explains the data, given their prior...

Adaptation to dynamic conditions requires a certain degree of diversity. If all agents take the best current action, learning that the underlying state has changed and behavior should adapt will be slower. Diversity is harder to maintain when there is fast communication between agents, because...

This paper explores how non-U.S. central banks behave when firms in their economies engage in currency mismatch, borrowing more heavily in dollars than justified by their operating exposures. We begin by documenting that, in a panel of 53 countries, central bank holdings of dollar reserves are...

This paper studies strategic decision making by a private currency ledger operator, which faces competition from public money and/or other ledgers. A monopoly ledger operator can incentivize contract enforcement across the financial sector by threatening exclusion, but it can also impose markups...

We provide a first look into the drivers of household cryptocurrency investing. Analyzing consumer transaction data for millions of U.S. households, we find that, except for high income early adopters, cryptocurrency investors resemble the general population. These investors span all income...

The evolution of the IMS and IFS in the past several hundred years can be viewed through the lens of the Copernican heliocentric system developed over 500 years ago. We trace out the evolution across regimes of the IMS and IFS in terms of network representations of the Copernican system. We...

I discuss private and central-bank-issued digital currencies, summarizing my prior research. I argue that prices of private digital currencies such as bitcoin follow random walks or, more generally, risk-adjusted martingales. For central bank digital currencies, I argue that they enhance the...