Person:

Mankiw, N

This paper surveys the research in the past decade on imperfect information models of aggregate supply and the Phillips curve. This new work has emphasized that information is dispersed and disseminates slowly across a population of agents who strategically interact in their use of information. We discuss the foundations on which models of aggregate supply rest, as well as the micro-foundations for two classes of imperfect information models: models with partial information, where agents observe economic conditions with noise, and models with delayed information, where they observe economic conditions with a lag. We derive the implications of these two classes of models for: the existence of a non-vertical aggregate supply, the persistence of the real effects of monetary policy, the difference between idiosyncratic and aggregate shocks, the dynamics of disagreement, and the role of transparency in policy. Finally, we present some of the topics on the research frontier in this area.

This paper is a contribution to the analysis of optimal monetary policy. It begins with a critical assessment of the existing literature, arguing that most work is based on implausible models of inflation-output dynamics. It then suggests that this problem may be solved with some recent behavioral models, which assume that price setters are slow to incorporate macroeconomic information into the prices they set. A specific such model is developed and used to derive optimal policy. In response to shocks to productivity and aggregate demand, optimal policy is price level targeting. Base drift in the price level, which is implicit in the inflation targeting regimes currently used in many central banks, is not desirable in this model. When shocks to desired markups are added, optimal policy is flexible targeting of the price level. That is, the central bank should allow the price level to deviate from its target for a while in response to these supply shocks, but it should eventually return the price level to its target path. Optimal policy can also be described as an elastic price standard: the central bank allows the price level to deviate from its target when output is expected to deviate from its natural rate.

Analyzing 50 years of inflation expectations data from several sources, we document substantial disagreement among both consumers and professional economists about expected future inflation. Moreover, this disagreement shows substantial variation through time, moving with inflation, the absolute value of the change in inflation, and relative price variability. We argue that a satisfactory model of economic dynamics must speak to these important business cycle moments. Noting that most macroeconomic models do not endogenously generate disagreement, we show that a simple sticky-information' model broadly matches many of these facts. Moreover, the sticky-information model is consistent with other observed departures of inflation expectations from full rationality, including autocorrelated forecast errors and insufficient sensitivity to recent macroeconomic news.

This paper develops and analyzes a general-equilibrium model with sticky information. The only rigidity in goods, labor, and financial markets is that agents are inattentive, sporadically updating their information sets, when setting prices, wages, and consumption. After presenting the ingredients of such a model, the paper develops an algorithm to solve this class of models and uses it to study the model's dynamic properties. It then estimates the parameters of the model using U.S. data on five key macroeconomic time series. It finds that information stickiness is present in all markets, and is especially pronounced for consumers and workers. Variance decompositions show that monetary policy and aggregate demand shocks account for most of the variance of inflation, output, and hours.

This paper assumes that a central bank commits itself to maintaining an inflation target and then asks what measure of the inflation rate the central bank should use if it wants to maximize economic stability. The paper first formalizes this problem and examines its microeconomic foundations. It then shows how the weight of a sector in the stability price index depends on the sector's characteristics, including size, cyclical sensitivity, sluggishness of price adjustment, and magnitude of sectoral shocks. When a numerical illustration of the problem is calibrated to U.S. data, one tentative conclusion is that a central bank that wants to achieve maximum stability of economic activity should use a price index that gives substantial weight to the level of nominal wages.

This paper examines a model of dynamic price adjustment based on the assumption that information disseminates slowly throughout the population. Compared with the commonly used sticky-price model, this sticky-information model displays three related properties that are more consistent with accepted views about the effects of monetary policy. First, disinflations are always contractionary (although announced disinflations are less contractionary than surprise ones). Second, monetary policy shocks have their maximum impact on inflation with a substantial delay. Third, the change in inflation is positively correlated with the level of economic activity.