Nonlinear income variance profiles and consumption inequality over the life cycle

In contrast to many other countries, consumption inequalities in Japan are not constant over household age but increase from around middle age--a fact first highlighted by Ohtake and Saito [Ohtake, F., Saito, M., 1998. Population aging and consumption inequality in Japan. Rev. Income Wealth 44, 361-381]. Given this information, we examine whether this phenomenon is consistent with the standard precautionary saving model developed by Carroll [Carroll, C.D., 1997. Buffer-stock savings and the life cycle/permanent income hypothesis. Quart. J. Econ. 62, 1-56]. Specifically, we investigate: (1) the degree of age dependence of idiosyncratic income risks; and (2) the importance of age dependence for the evolution of inequalities in consumption predicted by the household model of Carroll (1997). We find a strong age dependence of income risks, which creates a nonlinear age-variance profile of income, and the standard precautionary saving model is consistent with the observed consumption inequalities as long as we take the nonlinearity in age-variance profiles of income into account.