Benjamin D. Keen

What is a realistic value for price adjustment costs in New Keynesian models

Rotembergs (1982) price adjustment costs framework is a popular sticky price specification; yet, the data provides little information on the magnitude of those costs. This article finds a plausible range of parameterizations for those price adjustment costs. Our results show that the specific size of the price adjustment costs depends on the average markup of price over real marginal cost and the average time firms wait to reoptimize their price. In particular, the price adjustment costs are higher when the average markup is lower and the mean time between price reoptimizations is longer.

The Zero Lower Bound, the Dual Mandate, and Unconventional Dynamics

This paper examines monetary policy when it is constrained by the zero lower bound (ZLB) on the nominal interest rate. Our analysis uses a nonlinear New Keynesian model with technology and discount factor shocks. Specifically, we investigate why technology shocks may have unconventional effects at the ZLB, what factors affect the likelihood of hitting the ZLB, and the implications of alternative monetary policy rules. We initially focus on a New Keynesian model without capital (Model 1) and then study that model with capital (Model 2). The advantage of including capital is that it introduces another mechanism for intertemporal substitution that strengthens the expectational effects of the ZLB. Four main findings emerge: (1) In Model 1, the choice of output target in the Taylor rule may reverse the effects of technology shocks when the ZLB binds; (2) When the central bank targets steady-state output in Model 2, a positive technology shock at the ZLB leads to more pronounced unconventional dynamics than in Model 1; (3) The presence of capital changes the qualitative effects of demand shocks and alters the impact of a monetary policy rule that emphasizes output stability; and (4) In Model 1, the constrained linear solution is a decent approximation of the nonlinear solution, but meaningful differences exist between the solutions in Model 2.

Monetary Policy and Natural Disasters in a DSGE Model

In the immediate aftermath of Hurricane Katrina, speculation arose that the Federal Reserve might respond by easing monetary policy. This article uses a dynamic stochastic general equilibrium (DSGE) model to investigate the appropriate monetary policy response to a natural disaster. We show that the standard Taylor rule response in models with and without nominal rigidities is to increase the nominal interest rate. That finding is unchanged when we consider the optimal policy response to a disaster. A nominal interest rate increase following a disaster mitigates both temporary inflation effects and output distortions that are attributable to nominal rigidities.

Inflation risk and optimal monetary policy

This paper shows that the optimal monetary policies recommended by New Keynesian models still imply a large amount of inflation risk. We calculate the term structure of inflation uncertainty in New Keynesian models when the monetary authority adopts the optimal policy. When the monetary policy rules are modified to include some weight on a price path, the economy achieves equilibria with substantially lower long-run inflation risk. With either sticky prices or sticky wages, a price path target reduces the variance of inflation by an order of magnitude more than it increases the variability of the output gap.

The Zero Lower Bound and the Dual Mandate

This article uses a DSGE framework to evaluate the role of monetary policy in determining the likelihood of encountering the zero lower bound. We find that the probability of experiencing episodes of being at zero lower bound depends almost exclusively on the monetary policy rule. A policy rule, such as the one proposed by Taylor (1993) which is based on the dual mandate is highly likely to lead to episodes of zero short-term interest rates if the central bank is not committed to its inflation target. Our results on nominal interest rate and inflation dynamics do not depend on the particular mechanism that makes monetary policy have real effects. The key and necessary assumption is that expectations are forward looking. The bottom line in models in which monetary policy can influence the real economy is that a central bank must be committed to a long-run average-inflation objective if it wishes to achieve a dual mandate while avoiding the zero lower bound.

THE SIGNAL EXTRACTION PROBLEM REVISITED: A NOTE ON ITS IMPACT ON A MODEL OF MONETARY POLICY

This paper develops a dynamic stochastic general equilibrium (DSGE) model with sticky prices and sticky wages, in which agents have imperfect information on the stance and direction of monetary policy. Agents respond by using Kalman filtering to unravel persistent and temporary monetary policy changes in order to form optimal forecasts of future policy actions. Our results show that a New Keynesian model with imperfect information and real rigidities can account for several key effects of an expansionary monetary policy shock: the hump-shaped increase in output, the delayed and gradual rise in inflation, and the fall in the nominal interest rate.

Monetary policy and natural disasters in a DSGE model: how should the Fed have responded to Hurricane Katrina?

In the immediate aftermath of Hurricane Katrina, speculation arose that the Federal Reserve might respond by easing monetary policy. This paper uses a dynamic stochastic general equilibrium (DSGE) model to investigate the appropriate monetary policy response to a natural disaster. We show that the standard Taylor (1993) rule response in models with and without nominal rigidities is to increase the nominal interest rate. That finding is unchanged when we consider the optimal policy response to a disaster. A nominal interest rate increase following a disaster mitigates both temporary inflation effects and output distortions that are attributable to nominal rigidities.

FORWARD GUIDANCE AND THE STATE OF THE ECONOMY: FORWARD GUIDANCE

This paper analyzes forward guidance in a nonlinear model with a zero lower bound (ZLB) on the nominal interest rate. Forward guidance is modeled with news shocks to the monetary policy rule, which capture innovations in expectations from central bank communication about future policy rates. Whereas most studies use quasi‐linear models that disregard the expectational effects of hitting the ZLB, we show how the effectiveness of forward guidance nonlinearly depends on the state of the economy, the speed of the recovery, the degree of uncertainty, the policy shock size, and the forward guidance horizon when households account for the ZLB.

U.S. monetary policy: a view from macro theory

We use a dynamic stochastic general equilibrium model to address two questions about U.S. monetary policy: 1) Can monetary policy elevate output when it is below potential? and 2) Is the zero lower bound a trap? The model’s answer to the first question is yes it can, but the effect is only temporary and probably not welfare enhancing. The answer to the second question is more complicated because it depends on policy. It also depends on whether it is the inflation rate or the real interest rate that will adjust over the longer run if the policy rate is held near zero for an extended period. We use the Fisher equation to analyze possible outcomes for situations where the central bank has promised to keep the interest rate near zero for an extended period.

Taylor-Type Rules and Permanent Shifts in Productivity Growth

This paper examines the impact of a permanent shock to the productivity growth rate in a New Keynesian model when the central bank does not immediately adjust its policy rule to that shock. Our results show that inflation and productivity growth are negatively correlated at business cycle frequencies when the central bank follows a Taylor-type policy rule that targets the output gap. We then demonstrate that inflation is more stable after a permanent productivity shock when monetary policy targets the output growth rate (not the output gap) or the price-level path (not the inflation rate). As for the welfare implications, both the output growth and price-level path rules generate much less volatility in output and inflation after a productivity shock than occurs with the Taylor rule.