This paper argues that the primary objective of monetary policy should be long run price stability or at least a low average rate of in°ation. But there is also a welfare improving role for monetary policy in helping the economy adjust to nonpolicy shocks. This gives rise to a fundamental tension in the conduct of monetary policy. Understanding this tension is central to interpreting the qualitative properties of actual monetary policy, for evaluating its e®ects and for thinking about alternative institutions that would lead to better monetary policy. Is there a core of practical macroeconomics that we should all believe? 1 Given my limited space constraints, I won't try to discuss a top ten list of eternal macro truths. Nor will I discuss the importance of modelling macro phenomena using quantitative general equilibrium models. Instead I will approach the question from the perspective of stabilization policy. So de¯ned, my answer to the question is: Yes, there is a core of practical macro. And as regards stabilization policy, most of it has been learned in the past twenty eight years as

This paper analyzes the role of variable capital-utilization rates in propagating shocks over the business cycle. The model on which our analysis is based treats variable capital-utilization rates as a form of factor-hoarding. We argue that variable capital-utilization rates are a quantitatively important source of propagation to business-cycle shocks. With this additional source of propagation, the volatility of exogenous technology shocks needed to explain the observed variability in aggregate U.S. output is significantly reduced relative to standard real-business-cycle models.

Hours worked and the return to working are weakly correlated. Traditionally, the ability to account for this fact has been a litmus test for macroeconomic models. Existing real-business-cycle models fail this test dramatically. We modify prototypical real-business-cycle models by allowing government consumption shocks to influence labor-market dynamics. This modification can, in principle, bring the models into closer conformity with the data. Our empirical results indicate that it does.

This paper investigates whether there are simple versions of the permanent income hypothesis which are consistent with the aggregate U.S. consumption and output data. Our analysis is conducted within the confines of a simple dynamic general equilibrium model of aggregate real output, investment, hours of work and consumption. We study the quantitative importance of two perturbations to the version of our model which predicts that observed consumption follows a random walk: (i) changing the production technology specification which rationalizes the random walk result, and (ii) replacing the assumption that agents' decision intervals coincide with the data sampling interval with the assumption that agents make decisions on a continuous time basis. We find substantially less evidence against the continuous time models than against their discrete time counterparts. In fact neither of the two continuous time models can be rejected at conventional significance levels. The continuous time models outperform their discrete time counterparts primarily because they explicitly account for the fact that the data used to test the models are tine averaged measures of the underlying unobserved point-in-time variables. The net result is that they are better able to accommodate the degree of serial correlation present in the first difference of observed per capita U.S. consumption.

This paper investigates the sensitivity of Solow residual based measures of technology shocks to labor hoarding behavior. Using a structural model of labor hoarding and the identifying restriction that innovations to technology shocks are orthogonal to innovations in government consumption, we estimate the fraction of the variability of the Solow residual that is due to technology shocks. Our results support the view that a significant proportion of movements in the Solow residual are artifacts of labor hoarding behavior. Specifically, we estimate that the variance of innovations to technology is roughly 50 percent less than that implied by standard real business cycle models. In addition, our results suggest that existing real business cycle studies substantially overstate the extent to which technology shocks account for the variability of postwar aggregate U.S. output.

[We study the properties of the carry trade, a currency speculation strategy in which an investor borrows low-interest-rate currencies and lends high-interest-rate currencies. This strategy generates payoffs that are on average large and uncorrelated with traditional risk factors. We argue that these payoffs reflect a peso problem. The underlying peso event features high values of the stochastic discount factor rather than very large negative payoffs.]