Recent U.S. Macroeconomic Stability: Good Policies, Good Practices, or Good Luck?
利用频域和VAR方法分析1984年后美国GDP增长波动性下降的原因，发现外部冲击减少（好运气）是主因，而好政策和好做法对通胀波动下降更重要。
The volatility of U.S. real GDP growth since 1984 has been markedlylowerthanoverthepreviousquartercentury.Weutilizefrequency-domain and VAR methods to distinguish among competing explanations for this reduction: 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, suggesting that good luck is the most likely explanation. Good practices and good policy appear to have played a more important role in explaining the post-1984 decline in the volatility of consumer price inflation. © 2004 President and Fellows of Harvard College and the Massachusetts Institute of Technology.