The optimum quantity of debt
通过一个包含预防性储蓄和借贷约束的模型，发现美国当前债务水平与最优债务规模带来的福利差异很小，因此对高债务的担忧可能不必要。
We find that the welfare gains to being at the optimum quantity of debt rather than the current US level are small, and, therefore, concerns regarding the high level of debt in the US economy may be misplaced. This finding is based on a model of a large number of infinitely lived households whose saving behavior is influenced by precautionary saving motives and borrowing constraints. This model incorporates a different role for government debt than is found in standard models, and it captures different cost–benefit trade-offs. On the benefit side, government debt enhances the liquidity of households by providing an additional means of smoothing consumption and by effectively loosening borrowing constraints. On the cost side, the implied taxes have adverse wealth distribution and incentive effects. In addition, government debt crowds out capital via higher interest rates and lowers per capita consumption.