Short-term collateralized debt, such as demand deposits and money market instruments - private money, is efficient if agents are willing to lend without producing costly information about the collateral backing the debt. When the economy relies on such informationally-insensitive debt, firms...

To understand how best to combat COVID-19, we must understand how deadly is the disease. There is a substantial debate in the epidemiological lit- erature as to whether the fatality rate is 1% or 0.1% or somewhere in between. In this note, I use an SIR model to examine why it is difficult to...

This note is intended to introduce economists to a simple SIR model of the progression of COVID-19 in the United States over the next 12-18 months. An SIR model is a Markov model of the spread of an epidemic in a population in which the total population is divided into categories of being...

I present a behavioral epidemiological model of the evolution of the COVID epidemic in the United States and the United Kingdom over the past 12 months. The model includes the introduction of a new, more contagious variant in the UK in early fall and the US in mid December. The model is...

I use a model of private and public behavior to mitigate disease transmission during the COVID pandemic over the past year in the United States to address two questions: What dynamics of infections and deaths should we expect to see from a pandemic? What are our options for mitigating the impact...

The CDC reports that 1.13 million Americans have died of COVID-19 through June of 2023. I use a model of the impact over the past three years of vaccines and private and public behavior to mitigate disease transmission during the COVID-19 pandemic in the United States to address two questions....

Pricing complementarities play a key role in determining the propagation of monetary disturbances in sticky price models. We propose a procedure to infer the degree of firm-level pricing complementarities in the context of a menu cost model of price adjustment using data on prices and market...

We characterize equilibria with endogenous debt constraints for a general equilibrium economy with limited commitment in which the only consequence of default is losing the ability to borrow in future periods. First, we show that equilibrium debt limits must satisfy a simple condition that...

We develop a stylized currency crises model with heterogeneous information among investors and endogenous determination of interest rates in a noisy rational expectations equilibrium. Our model captures three key features of interest rates: the opportunity cost of attacking the currency responds...

Global games of regime change -- that is, coordination games of incomplete information in which a status quo is abandoned once a sufficiently large fraction of agents attacks it -- have been used to study crises phenomena such as currency attacks, bank runs, debt crises, and political change. We...