Optimal monetary policy

Optimal monetary policy maximizes the welfare of a representative agent, given frictions in the economic environment. Constructing a model with two broad sets of frictions — costly price adjustment by imperfectly competitive firms and costly exchange of wealth for goods — we find optimal monetary policy is governed by two familar principles. ; First, the average level of the nominal interest rate should be sufficiently low, as suggested by Milton Friedman, that there should be deflation on average. Yet, the Keynesian frictions imply that the optimal nominal interest rate is positive. ; Second, as various shocks occur to the real and monetary sectors, the price level should be largely stabilized, as suggested by Irving Fisher, albeit around a deflationary trend path. (In modern language, there is only small “base drift” for the price level path as various shocks arise). Since expected inflation is roughly constant through time, the nominal interest rate must therefore vary with the Fisherian determinants of the real interest rate, i.e., with expected growth or contraction of real economic activity. ; Although the monetary authority has substantial leverage over real activity in our model economy, it chooses real allocations that closely resemble those that would occur if prices were flexible. In our benchmark model, we also find some tendency for the monetary authority to smooth nominal and real interest rates.Monetary policy

Optimal Inflation Policy

This paper considers the problem of optimal long run monetary policy. It shows that optimal inflation policy involves trading off two quite different considerations. First, increases in the rate of inflation tax the holding of many balances, leading to a deadweight loss as excessive resources are devoted to economizing on cash balances. Second, increases in the rate of inflation raise capital intensity. As long as the economy has a capital stock short of the golden rule level, increases in capita intensity raise the level of consumption. Ignoring the second consideration leads to the common recommendation that the money growth rate be set so that the nominal interest rate is zero. Taking it into account can lead to significant modifications in the "full liquidity rule." Inter-actions of inflation policy with financial intermediation and taxation are also considered. The results taken together suggest that inflation can have important welfare effects, and that optimal inflation policy is an empirical question, which depends on the structure of the economy.

Optimal Policy Projections

We outline a method to provide advice on optimal monetary policy while taking policymakers' judgment into account. The method constructs Optimal Policy Projections (OPPs) by extracting the judgment terms that allow a model, such as the Federal Reserve Board's FRB/US model, to reproduce a forecast, such as the Greenbook forecast. Given an intertemporal loss function that represents monetary policy objectives, OPPs are the projections - of target variables, instruments, and other variables of interest -that minimize that loss function for given judgment terms. The method is illustrated by revisiting the Greenbook forecasts of February 1997 and November 1999, in each case using the vintage of the FRB/US model that was in place at that time. These two particular forecasts were chosen, in part, because they were at the beginning and the peak, respectively, of the late 1990s boom period. As such, they differ markedly in their implied judgments of the state of the world, and our OPPs illustrate this difference. For a conventional loss function, our OPPs provide significantly better performance than Taylor-rule simulations.

Optimal Policy Projections

We outline a method to provide advice on optimal monetary policy while taking policymakers’ judgment into account. The method constructs optimal policy projections (OPPs) by extracting the judgment terms that allow a model, such as the Federal Reserve Board staff economic model, FRB/US, to reproduce a forecast, such as the Greenbook forecast. Given an intertemporal loss function that represents monetary policy objectives, OPPs are the projections — of target variables, instruments, and other variables of interest — that minimize that loss function for given judgment terms. The method is illustrated by revisiting the economy of early 1997 as seen in the Greenbook forecasts of February 1997 and November 1999. In both cases, we use the vintage of the FRB/US model that was in place at that time. These two particular forecasts were chosen, in part, because they were at the beginning and the peak, respectively, of the late 1990s boom period. As such, they differ markedly in their implied judgments of the state of the world in 1997 and our OPPs illustrate this difference. For a conventional loss function, our OPPs provide significantly better performance than Taylor-rule simulations.

Optimal maintenance strategies for systems with partial repair options and without assuming bounded costs

We study a repairable system with Markovian deterioration and partial repair options, carried out at fixed times $n=1,2,\ldots$ and look for optimal strategies under certain conditions. Two optimality criteria are considered: expected discounted cost and long-run average cost. Douer and Yechiali found conditions under which a policy in the class of generalized control limit policies is optimal. In this paper conditions are found under which an optimal policy is a control-limit policy. We explicitly explain how to derive this optimal policy; numerical examples are given, too

Unconditionally Optimal Monetary Policy

We develop a simple and intuitive approach for analytically deriving unconditionally optimal (UO) policies, a topic of enduring interest in optimal monetary policy analysis. The approach can be employed to both general linear-quadratic problems and to the underlying non-linear environments. We provide a detailed example using a canonical New Keynesian framework.Unconditional expectations, optimal monetary policy.

Pollution, mortality and optimal environmental policy

We study an overlapping generations economy in which environmental degradation results from economic activity and affects agents' uncertain lifetimes. Life expectancy depends positively on economic activity and negatively on the stock of pollution. This can make the growth-survival relationship convex over some region and lead to two non-trivial steady states, with one a poverty trap. Uniform abatement taxes can cause the poverty trap to widen while increasing incomes at the high steady state. We also study the properties and dynamics of an optimal second-best abatement tax. It is non-homogeneous and increasing in the capital stock, and leads to a variety of dynamic possibilities, including non-existence and multiplicity of steady states, and cycles around some of the steady states, where there were none under exogenous taxes. Thus, optimal taxes can be an independent source of non-linearities

An optimal repartitioning decision policy

A central problem to parallel processing is the determination of an effective partitioning of workload to processors. The effectiveness of any given partition is dependent on the stochastic nature of the workload. The problem of determining when and if the stochastic behavior of the workload has changed enough to warrant the calculation of a new partition is treated. The problem is modeled as a Markov decision process, and an optimal decision policy is derived. Quantification of this policy is usually intractable. A heuristic policy which performs nearly optimally is investigated empirically. The results suggest that the detection of change is the predominant issue in this problem

Openness and optimal monetary policy

We show that the composition of imports has important implications for the optimal volatility of the exchange rate. Using input-output data for 25 countries we document substantial differences in the import and non-tradable content of final demand components, and in the role played by imported inputs in domestic production. We build a business cycle model of a small open economy to discuss how the problem of the optimizing policy-maker changes endogenously as the composition of imports and of final demand is altered. Contrary to models where steady state trade openness is entirely characterized by home bias, we find that trade openness is a very poor proxy of the welfare impact of alternative monetary policies. Finally, we quantify the loss from an exchange rate peg relative to the Ramsey policy conditional on the composition of imports, using parameter values that are estimated from OECD input-output tables data. We find that the main determinant of the losses is the share of non-traded goods in final demand. JEL Classification: E52, E31, F02, F41Exchange Rate Regimes, international trade, Non-tradable Goods, Optimal Policy