This paper examines fiscal policy forecasts prepared for the Federal Open Market Committee and its influence on U.S. monetary policy. The forecasts contain useful information beyond that in the CBO’s forecasts. Fiscal forecast errors are only weakly correlated with forecast errors for inflation and output growth, but those for the budget surplus are highly correlated with those for the unemployment rate and the output gap. Some fiscal variables can also account for a significant fraction of the “exogenous” changes in the federal funds rate target that Romer and Romer (2004) studied, consistent with the board’s statements on the importance of fiscal policy.

We examine the reliability of alternative output detrending methods, with special attention to the accuracy of real-time estimates of the output gap. We show that ex post revisions of the estimated gap are of the same order of magnitude as the estimated gap itself and that these revisions are highly persistent. Although important, the revision of published data is not the primary source of revisions in measured output gaps; the bulk of the problem is due to the pervasive unreliability of end-of-sample estimates of the trend in output. Multivariate methods that incorporate information from inflation to estimate the output gap are not more reliable than their univariate counterparts.