Precautionary Savings and the Permanent Income Hypothesis
推导了无限期寿命消费者在非多样化劳动收入不确定性下的最优消费显式解，假设跨期替代弹性恒定且绝对风险厌恶恒定，为预防性储蓄动机提供了简洁表达。
This paper derives the explicit solution of a dynamic stochastic optimal consumption problem for infinitely-lived agents whose preferences exhibit, in the presence of non-diversifiable labour income uncertainty, a constant elasticity of intertemporal substitution and constant absolute risk aversion. The constancy of the elasticity of intertemporal substitution, which implies that marginal utility at zero consumption is infinite, guarantees that the non-negativity constraint on consumption is never binding along the optimal path. The assumption of constant absolute risk aversion allows an explicit computation of human wealth, and provides a simple representation of the precautionary savings motive.