Abstract not found

This paper reviews Bayesian methods that have been developed in recent years to estimate and evaluate dynamic stochastic general equilibrium (DSGE) models. We consider the estimation of linearized DSGE models, the evaluation of models based on Bayesian model checking, posterior odds comparisons, and comparisons to vector autoregressions, as well as the nonlinear estimation based on a second-order accurate model solution. These methods are applied to data generated from correctly specified and misspecified linearized DSGE models, and a DSGE model that was solved with a second-order perturbation method. (JEL C11, C32, C51, C52)

Abstract not found

This paper identifies optimal interest-rate rules within a rich, dynamic, general equilibrium model that has been shown to account well for observed aggregate dynamics in the postwar United States. We perform policy evaluations based on second-order accurate approximations to conditional and unconditional expected welfare. We require that interest-rate rules be operational, in the sense that they include as arguments only a few readily observable macroeconomic indicators and respect the zero bound on nominal interest rates. We find that the optimal operational monetary policy is a real-interest-rate targeting rule. That is, an interest-rate feedback rule featuring a unit inflation coefficient, a mute response to output, and no interest-rate smoothing. Contrary to existing studies, we find a significant degree of optimal inflation volatility. A key factor driving this result is the assumption of indexation to past inflation. Under indexation to long-run inflation the optimal inflation volatility is close to zero. Finally, we show that initial conditions matter for welfare rankings of policies. JEL

oPtimal monetary Policy in a neW keyneSian model

We consider a general class of nonlinear optimal policy problems involving forward-looking constraints (such as the Euler equations that are typically present as structural equations in DSGE models), and show that it is possible, under regularity conditions that are straightforward to check, to derive a problem with linear constraints and a quadratic objective that approximates the exact problem. The LQ approximate problem is computationally simple to solve, even in the case of moderately large state spaces and flexibly parameterized disturbance processes, and its solution represents a local linear approximation to the optimal policy for the exact model in the case that stochastic disturbances are small enough. We derive the second-order conditions that must be satisfied in order for the LQ problem to have a solution, and show that these are stronger, in general, than those required for LQ problems without forwardlooking constraints. We also show how the same linear approximations to the model structural equations and quadratic approximation to the exact welfare measure can be used to correctly rank alternative simple policy rules, again in the case of small enough shocks.

We study the the emergence of multiple equilibria in models with capital and bonds under various monetary and …scal policies. We show that the presence of capital is indeed another independent source of local and global multiplicites, even under active policies that yield local determinacy. We also show how a very similar mechanism generates multiplicities in models with bonds and distortionary taxation. We then explore the design of monetary policies that avoid multiple equilibria. We show that interest rate policies that respond to the output gap, while potentially a source of signi…cant ine ¢ ciencies, may be e¤ective in preventing multiple equilibria and costly oscillatory equilibrium dynamics.

Observed inflation targets around the industrial world are concentrated at two percent per year. This chapter investigates the extent to which the observed magnitudes of inflation targets are consistent with the optimal rate of inflation predicted by leading theories of monetary nonneutrality. We find that consistently those theories imply that the optimal rate of inflation ranges from minus the real rate of interest to numbers insignificantly above zero. Furthermore, we argue that the zero bound on nominal interest rates does not represent an impediment for setting inflation targets near or below zero. Finally, we find that central banks should adjust their inflation targets upward by the size of the quality bias in measured inflation only if hedonic prices are more sticky than are non-quality-adjusted prices.

This Working Paper should not be reported as representing the views of the IMF. The views expressed in this Working Paper are those of the author(s) and do not necessarily represent those of the IMF or IMF policy. Working Papers describe research in progress by the author(s) and are published to elicit comments and to further debate. This paper studies overborrowing, financial crises and macro-prudential policy in an equilibrium model of business cycles and asset prices with collateral constraints. Agents in a decentralized competitive equilibrium do not internalize the negative effects of asset fire-sales on the value of other agents ' assets and hence they borrow too much " ex ante, compared with a constrained social planner who internalizes these effects. Average debt and leverage ratios are slightly larger in the competitive equilibrium, but the incidence and magnitude of financial crises are much larger. Excess asset returns, Sharpe ratios and the market price of risk are also much larger. State-contigent taxes on debt and dividends of about 1 and-0.5 percent on average respectively support the planner’s allocations as a competitive equilibrium and increase

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