In monetary unions, a time inconsistency problem in monetary policy leads to a novel type of free-rider problem in the setting of non-monetary policies. The free-rider problem leads union members to pursue lax non-monetary policies that induce the monetary authority to generate high inflation....

In standard monetary policy approaches, interest-rate rules often produce indeterminacy. A sophisticated policy approach does not. Sophisticated policies depend on the history of private actions, government policies, and exogenous events and can differ on and off the equilibrium path. They can...

The classic optimal currency area criterion is that countries with more correlated shocks are better candidates to form a union. We show that when countries have credibility problems this simple criterion must be changed: Symmetric countries gain credibility when joining the union only when the...

We propose a simple method to help researchers develop quantitative models of economic fluctuations. The method rests on the insight that many models are equivalent to a prototype growth model with time-varying wedges which resemble productivity, labor and investment taxes, and government...

We provide an introduction to optimal fiscal and monetary policy using the primal approach to optimal taxation. We use this approach to address how fiscal and monetary policy should be set over the long run and over the business cycle. We find four substantive lessons for policymaking: Capital...