A Theory of the Consumption Function, With and Without Liquidity Constraints
论证现代随机消费模型比完美预见模型更符合弗里德曼的永久收入假说，能解释高边际消费倾向、高贴现率和预防性行为，并指出预防性储蓄与流动性约束效果难以区分。
This paper argues that the modern stochastic consumption model, in which impatient consumers face uninsurable labor income risk, matches Milton Friedman's (1957) original description of the Permanent Income Hypothesis much better than the perfect foresight or certainty equivalent models did. The model can explain the high marginal propensity to consume, the high discount rate on future income, and the important role for precautionary behavior that were all part of Friedman's original framework. The paper also explains the relationship of these questions to the Euler equation literature, and argues that the effects of precautionary saving and liquidity constraints are often virtually indistinguishable.