Asset pricing theory has long recognized that financial markets compensate investors who are exposed to some components of uncertainty. This is where macroeconomics comes into play. The economy-wide shocks, the primary concern of macroeconomists, by their nature are not diversifiable. Exposures...

The standard theory of decision making under uncertainty advises the decision maker to form a statistical model linking outcomes to decisions and then to choose the optimal distribution of outcomes. This assumes that the decision maker trusts the model completely. But what should a decision...