Roy H. Webb

Defining and Improving the Accuracy of Macroeconomic Forecasts: Contributions from a VAR Model

Thirty years ago it appeared that the best strategy for improving economic forecasts was to build bigger, more detailed models. As the costs of computing plummeted, considerable detail was added to models and more elaborate statistical techniques became feasible.

Forecasts of Inflation from VAR Models

Why are forecasts of inflation from VAR models so much worse then their forecasts of real variables? This paper documents that relatively poor performance, and finds that the price equation of a VAR model fitted to U.S. postwar data is poorly specified. Statistical work by other authors has found that coefficients in such price equations may not be constant. Based on specific monetary actions, two changes in monetary policy regimes are proposed. Accounting for those two shifts yields significantly more accurate forecasts and lessens the evidence of misspecification.

Inadequate Tests of the Rationality of Expectations

In several recent articles, authors have regressed actual values of macroeconomic aggregates on predicted values and claimed that they were testing the rationality of expectations. This paper interprets those regressions as testing a joint hypothesis of imperfect information and rational expectations. An empirical method is proposed to separate the components of the joint hypothesis. Predictions from two major forecasting services are examined, and results are found that are consistent with rational expectations but inconsistent with the joint hypothesis. It is therefore argued that many purported tests of rational expectations are inadequate.