Over the past thirty years, a great deal of business cycle research has been based on purely real models that abstract from the presence of nominal rigidities, and so (at least implicitly) assume that the Phillips curve is vertical. In this paper, I show that such models are fragile, in the...

In this paper, we measure the potential welfare gains from counter-cyclical policy in an economy with incomplete markets. In the course of conducting this measurement, we focus on two questions as central to the determination of those potential gains: (1) what is the likely effect of...

We develop a simple dynamic economic model of epidemic transmission designed to be consistent with widely used SIR biological models of the transmission of epidemics, while incorporating economic benefits and costs as well. Our main finding is that targeted testing and isolation policies deliver...

This paper presents a continuous-time model of sovereign debt. In it, a relatively impatient sovereign government's hidden type switches back and forth between a commitment type, which cannot default, and an optimizing type, which can default at any time, and assume outside lenders have...

This paper presents a continuous-time reputation model of sovereign debt allowing for both varying levels of partial default and full default. In it, a government can be a non-strategic commitment type, or a strategic opportunistic type, and a government's reputation is its equilibrium Bayesian...

Inherent in the definition of Pareto efficiency is the idea that, in dynamic environments, an individual is indexed by the history of events up to his birth (rather than, as usual, the date of birth). Here, we explore the implications of this natural formulation. The set of Pareto efficient...

We analyze a new class of equilibria that emerges when a central bank conducts monetary policy by setting an interest rate (as an arbitrary function of its available information) and letting the private sector set the quantity traded. These equilibria involve a run on the central bank's interest...

Early cash-in-advance models have the feature that the cash-in-advance constraint always binds, implying that the velocity of money is constant. Lucas (1984) and Svensson (1985) propose a change in information structure that potentially allows velocity to vary. By calibrating a version of these...

I reconsider the long-standing consensus view that macroeconomic stabilization should rely on monetary policy, not fiscal policy. I use an analytically tractable heterogeneous agent New Keynesian (HANK) model that is parameterized so as to admit a bubble in public debt. In this context, I show...

In this paper, we consider economies in which agents are privately informed about their skills, which are evolving stochastically over time. We require agents' preferences to be weakly separable between the lifetime paths of consumption and labor. However, we allow for intertemporal...