Credit Constraints, Learning and Aggregate Consumption Volatility

This paper documents three empirical facts. First, the volatility of consumption growth relative to income growth rose from 1947-1960 and then fell dramatically by 50 percent from the 1960s to the 1990s. Second, the correlation between consumption growth and personal income growth fell by about 50 percent over the same time period. Finally, the absolute deviation of consumption growth from its mean exhibits one break in U.S. data, and the mean of the absolute deviations has fallen by about 30 percent. First, I find that a standard dynamic, stochastic general equilibrium model is unable to explain these facts. Then, I examine the ability of two hypotheses: a fall in credit constraints and changing beliefs about the permanence of income shocks to account for these facts. I find evidence for both explanations and the beliefs explanation is more consistent with the data. Importantly, I find that estimated changes in beliefs about the permanence of income shocks have significant explanatory power for consumption changes.