Riskless interest rates fell in the wake of the financial crisis and have remained low. We explore a simple explanation: This recession was perceived as an extremely unlikely event before 2007. Observing such an episode led all agents to re-assess macro risk, in particular, the probability of...

A representative investor does not know which member of a set of well-defined parametric "structured models'' is best. The investor also suspects that all of the structured models are misspecified. These uncertainties about probability distributions of risks give rise to components of...

The largest economic cost of the COVID-19 pandemic could arise from changes in behavior long after the immediate health crisis is resolved. A potential source of such a long-lived change is scarring of beliefs, a persistent change in the perceived probability of an extreme, negative shock in the...

This paper explores two perspectives on the rational expectations hypothesis. One perspective is that of economic agents in such a model, who form inferences about the future using probabilities implied by the model. The other is that of an econometrician who makes inferences about the...

The Great Recession was a deep downturn with long-lasting effects on credit markets, labor markets and output. While narratives about what caused the recession abound, the persistence of GDP below its pre-crisis trend is puzzling. We propose a simple persistence mechanism that can be easily...

We must infer what the future situation would be without our interference, and what changes will be wrought by our actions. Fortunately, or unfortunately, none of these processes is infallible, or indeed ever accurate and complete. Knight (1921)