The volatility of U.S. real GDP growth since 1984 has been markedly lower than that over the previous quarter-century. In this paper, we utilize frequency-domain and VAR methods to distinguish among several competing explanations for this phenomenon: improvements in monetary policy, better business practices, and a fortuitous reduction in exogenous disturbances. We find that reduced innovation variances account for much of the decline in aggregate output volatility. Our results support the "good-luck" hypothesis as the leading explanation for the decline in aggregate output volatility, although "good-practices" and "good-policy" are also contributing factors. Applying the same methods to consumer price inflation, we find that the post-1984 decline in inflation volatility can be attributed largely to improvements in monetary policy.

We examine the extent of downward nominal wage rigidity using the microdata underlying the BLS employment cost index--an extensive, establishment-based dataset with detailed information on wage and benefit costs. We find stronger evidence of downward nominal wage rigidity than did previous studies using panel data on individuals. Firms appear able to circumvent part, but not all, of this rigidity by varying benefits: Total compensation displays modestly less rigidity than do wages alone. Given our estimated amount of rigidity, a simple model predicts that the disinflation over the 1980s would have raised equilibrium unemployment notably. This prediction stands in contrast to the actual behavior of unemployment over this period: The addition of a term capturing the cost of rigidity (that rises as inflation falls) has no additional explanatory power in a standard Phillips Curve equation.

The volatility of U.S. real GDP growth since 1984 has been markedly lower than that over the previous quarter-century. In this paper, we utilize frequency-domain and VAR methods to distinguish among several competing explanations for this phenomenon: improvements in monetary policy, better business practices, and a fortuitous reduction in exogenous disturbances. We find that reduced innovation variances account for much of the decline in aggregate output volatility. Our results support the "good-luck" hypothesis as the leading explanation for the decline in aggregate output volatility, although "good-practices" and "good-policy" are also contributing factors. Applying the same methods to consumer price inflation, we find that the post-1984 decline in inflation volatility can be attributed largely to improvements in monetary policy.