The Great Moderation and the Relationship between Output Growth and Its Volatility

This study examines the effect of the Great Moderation on the relationship between U.S. output growth and its volatility over the period 1947 to 2006. First, we consider the possible effects of structural change in the volatility process. In so doing, we employ GARCH-M and ARCH-M specifications of the process describing output growth rate and its volatility with and without a one-time structural break in volatility. Second, our data analyses and empirical results suggest no significant relationship between the output growth rate and its volatility, favoring the traditional wisdom of dichotomy in macroeconomics. Moreover, the evidence shows that the time-varying variance falls sharply or even disappears once we incorporate a one-time structural break in the unconditional variance of output starting 1982 or 1984. That is, the integrated GARCH effect proves spurious. Finally, a joint test of a trend change and a one-time shift in the volatility process finds that the one-time shift dominates.

Is the Great Moderation Ending? UK and US Evidence

The Great Moderation, the significant decline in the variability of economic activity, provides a most remarkable feature of the macroeconomic landscape in the last twenty years. A number of papers document the beginning of the Great Moderation in the US and the UK. In this paper, we use the Markov regime-switching models of Hamilton (1989) and Hamilton and Susmel (1994) to document the end of the Great Moderation. The Great Moderation in the US and the UK begin at different point in time. The explanations for the Great Moderation fall into generally three different categories -- good monetary policy, improved inventory management, or good luck. Summers (2005) argues that a combination of good monetary policy and better inventory management led to the Great Moderation. The end of the Great Moderation, however, occurs at approximately the same time in both the US and the UK. It seems unlikely that good monetary policy would turn into bad policy or that better inventory management would turn into worse management. Rather, the likely explanation comes from bad luck. Two likely culprits exist . energy-price and housing-price shocks.

The Great Moderation Flattens Fat Tails: Disappearing Leptokurtosis

Recently, Fagiolo et al. (2008) find fat tails of economic growth rates after adjusting outliers, autocorrelation and heteroskedasticity. This paper employs US quarterly real output growth, showing that this finding of fat tails may reflect the Great Moderation. That is, leptokurtosis disappears after GARCH adjustment once we incorporate the break in the variance equation.