"This paper provides an introduction to predictable forecast uncertainty in empirical economic modelling. The sources of both predictable and unpredictable forecast uncertainty are categorized. Key features of predictable forecast uncertainty are illustrated by several analytical models, including static and dynamic models, and single-equation and multiple-equation models. Empirical models of the U.S. trade account, U.K. inflation, and U.K. real national income help clarify the issues involved"--Federal Reserve Board web site.