Optimal Simple and Implementable Monetary and Fiscal Rules: Expanded Version

This paper computes welfare-maximizing monetary and fiscal policy rules in a real business cycle model augmented with sticky prices, a demand for money, taxation, and stochastic government consumption. We consider simple feedback rules whereby the nominal interest rate is set as a function of output and inflation, and taxes are set as a function of total government liabilities. We implement a second-order accurate solution to the model. Our main findings are: First, the size of the inflation coefficient in the interest-rate rule plays a minor role for welfare. It matters only insofar as it affects the determinacy of equilibrium. Second, optimal monetary policy features a muted response to output. More importantly, interest rate rules that feature a positive response to output can lead to significant welfare losses. Third, the welfare gains from interest-rate smoothing are negligible. Fourth, optimal fiscal policy is passive. Finally, the optimal monetary and fiscal rule combination attains virtually the same level of welfare as the Ramsey optimal policy.