Research Publication

November 2009 | Article

Doubts or Variability?

Francisco Barillas, Lars Peter Hansen, Thomas J. Sargent

Reinterpreting most of the market price of risk as a price of model uncertainty eradicates a link between asset prices and measures of the welfare costs of aggregate fluctuations that was proposed by Hansen, Sargent, and Tallarini [17], Tallarini [30], Alvarez and Jermann [1]. Prices of model uncertainty contain information about the benefits of removing model uncertainty, not the consumption fluctuations that Lucas [22] and [23] studied. A max–min expected utility theory lets us reinterpret Tallarini’s risk-aversion parameter as measuring a representative consumer’s doubts about the model specification. We use model detection instead of risk-aversion experiments to calibrate that parameter. Plausible values of detection error probabilities give prices of model uncertainty that approach the Hansen and Jagannathan [11] bounds. Fixed detection error probabilities give rise to virtually identical asset prices as well as virtually identical costs of model uncertainty for Tallarini’s two models of consumption growth.

Journal: Journal of Economic Theory|Volume: 144|Issue Number: 6|Pages: 2388-2418|Tags: Risk, Robustness and Ambiguity|Export BibTeX >
  title={Doubts or Variability?},
  author={Barillas, Francisco and Hansen, Lars Peter and Sargent, Thomas J},
  journal={journal of economic theory},