The Role of Models and Probabilities in the Monetary Policy Process

The primary models in use as part of the policy process in central banks are deeply flawed, both from the point of view of econometric analysis and from the point of view of economic theory. "Subjective" approaches to forecasting play a major role in policy formation in every central bank, and data on the forecasting record of FRB nonmodel forecasts shows that they are excellent forecasts by several measures. Academic research on econometric method and on macroeconomic theory has not provided much guidance for model builders who need to contribute to policy analysis in real time. Policy discussion at central banks uses the language of Bayesian decision theory -putting postsample probabilities on models, generating probability distributions for future values of variables that reflect uncertainty about parameter values and subjective judgment, weighing expected losses of alternative courses of action. But the standard toolkit of econometrics does not connect to this way of thinking about probability. There is some reason to hope for improvement before long.