The Optimum Quantity of Money: Theory and Evidence
提出一个计算最优通货膨胀税的通用模型，发现弗里德曼规则是否最优取决于货币需求规模弹性等可测变量，并用实证校准得出最优名义利率低于每年1%。
In this paper we propose a simple and general model for computing the \nRamsey optimal inflation tax, which includes several models from the \nprevious literature as special cases. We show that it cannot be claimed \nthat the Friedman rule is always optimal (or always non--optimal) on \ntheoretical grounds. The Friedman rule is optimal or not, depending on \nconditions related to the shape of various relevant functions. One \ncontribution of this paper is to relate these conditions to {\\it measurable} \nvariables such as the interest rate or the consumption elasticity of money \ndemand. We find that it tends to be optimal to tax money when there are \neconomies of scale in the demand for money (the scale elasticity is \nsmaller than one) and/or when money is required for the payment of \nconsumption or wage taxes. We find that it tends to be optimal to tax \nmoney more heavily when the interest elasticity of money demand is \nsmall. We present empirical evidence on the parameters that determine \nthe optimal inflation tax. Calibrating the model to a variety of empirical \nstudies yields a optimal nominal interest rate of less than 1\\%/year, \nalthough that finding is sensitive to the calibration.