The Great Moderation in Micro Labor Earnings

John Sabelhaus, Jae Song , Journal of Monetary Economics 57(4) , 391-403 , May 2010.

Between 1980 and the early 1990s the variability of labor earnings growth rates across the prime-age working population fell significantly. This decline and timing are consistent with other macro and micro observations about growth variability that are collectively referred to as the “Great Moderation.” The variability of earnings growth is negatively correlated with age at any point in time, and the U.S. working age population got older during this period because the Baby Boom was aging. However, the decrease in variability was roughly uniform across all age groups, so population aging is not the source of the overall decline. The variance of log changes also declined at multi-year frequencies in such a way as to suggest that both permanent and transitory components of earnings shocks became more moderate. A simple identification strategy for separating age and cohort effects shows a very intuitive pattern of permanent and transitory shocks over the life cycle, and confirms that a shift over time in the stochastic process occurred even after controlling for age effects.

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