The Life Cycle Hypothesis and Rational Expectations: Some Further Empirical Results

Abstract

In an innovative and important paper Hall (1978) demonstrated that the assumption of rational expectations when applied to the life cycle or permanent income hypothesis would, given a number of further assumptions such as constancy of the real rate of interest, imply that real consumption follows a martingale. Thus in logarithmslog C - log C- 1 = α + ∊where C is real consumer expenditure, α is a constant which allows for real growth in the economy and ∊ is a white noise error term.Hall presented empirical evidence for the U.S. economy which was broadly consistent with the hypothesis. However, subsequent work by a number of authors (eg Muellbauer (1983) and Hendry and von Ungern-Sternberg (1980)) appears to be inconsistent with the hypothesis. Past values of economic variables, such as consumption or income, are significant determinants of the first difference of the logarithm of consumption which violates the hypothesis.