Optimal monetary policy maximizes welfare, given frictions in the economic environment. Constructing a model with two sets of frictions - the Keynesian friction of costly price adjustment by imperfectly competitive firms and the Monetarist friction of costly exchange of wealth for goods - we...

A discretionary policymaker responds to the state of the economy each period. Private agents' current behavior determines the future state based on expectations of future policy. Discretionary policy thus can lead to dynamic complementarity between private agents and a policymaker, which in turn...

In a canonical staggered pricing model, monetary discretion leads to multiple private sector equilibria. The basis for multiplicity is a form of policy complementarity. Specifically, prices set in the current period embed expectations about future policy, and actual future policy responds to...

If monetary policy succeeds in keeping average inflation very low, nominal interest rates may occasionally be constrained by the zero lower bound. The degree to which this constraint has real implications depends on the monetary policy feedback rule and the structure of price-setting. Policy...

The analysis in Ball and Romer [1991] suggests that models with fixed costs of changing price may be rife with multiple equilibria; in their static model price adjustment is always characterized by strategic complementarity, a necessary condition for multiplicity. We extend Ball and Romer's...