Stock Prices and Monetary Policy. CEPS Working Document No. 304, September 2008

The question of whether central banks should target stock prices so as to prevent bubbles and crashes from occurring has been hotly debated. This paper analyses this question using a behavioural macroeconomic model. This model generates bubbles and crashes. It analyses how ‘leaning against the wind’ strategies, which aim to reduce the volatility of stock prices, can help in reducing volatility of output and inflation. We find that such policies can be effective in reducing macroeconomic volatility, thereby improving the trade-off between output and inflation variability. The strength of this result, however, depends on the degree of credibility of the inflation-targeting regime. In the absence of such credibility, policies aiming at stabilising stock prices do not stabilise output and inflation

Learning as a rational foundation for macroeconomics and finance

Expectations play a central role in modern macroeconomics. The econometric learning approach, in line with the cognitive consistency principle, models agents as forming expectations by estimating and updating subjective forecasting models in real time. This approach provides a stability test for RE equilibria and a selection criterion in models with multiple equilibria. Further features of learning – such as discounting of older data, use of misspecified models or heterogeneous choice by agents between competing models – generate novel learning dynamics. Empirical applications are reviewed and the roles of the planning horizon and structural knowledge are discussed. We develop several applications of learning with relevance to macroeconomic policy: the scope of Ricardian equivalence, appropriate specification of interest-rate rules, implementation of price-level targeting to achieve learning stability of the optimal RE equilibrium and whether, under learning, price-level targeting can rule out the deflation trap at the zero lower bound.cognitive consistency; E-stability; least-squares; persistent learning dynamics; business cycles; monetary policy; asset prices

Evidence from surveys of price-setting managers: Policy lessons and directions for ongoing research

Understanding the determinants of individual price setting behaviour is crucial for the formulation of monetary policy, especially in an economy experiencing ongoing structural change. These behavioural mechanisms play a fundamental role in influencing the characteristics of aggregate inflation and in determining how monetary policy affects inflation and real economic activity. Thus, this line of research can strengthen the conceptual foundations of general equilibrium models with sticky prices, enabling these models to provide monetary policymakers with an increasingly useful framework for interpreting and forecasting the evolution of the macroeconomy. In this paper, we introduce the Walrasian model as a benchmark for comparison, and we discuss the extent to which recent micro evidence on firms’ price setting behavior provides significant support for some basic elements of the New Keynesian perspective. We then proceed to analyze the implications of the micro evidence in distinguishing between competing theories of price stickiness. Finally, the paper concludes with some brief reflections about the lessons for monetary policy.

Booms and Busts: New Keynesian and Behavioral Explanations

Capitalism is characterized by booms and busts. Periods of strong growth in output alternate with periods of declines in economic growth. Every macro-economic theory should attempt to explain these endemic business cycle movements. In this paper I present two paradigms that attempt to explain these booms and busts. One is the DSGE-paradigm in which agents have unlimited cognitive abilities. The other paradigm is a behavioural one in which agents are assumed to have limited cognitive abilities. These two types of models produce a radically different macroeconomic dynamics. I analyze these differences. I also study the different policy implications of these two paradigms.DSGE-model, imperfect information, heuristics, animal spirits

Top-Down versus Bottom-Up Macroeconomics

I distinguish two types of macroeconomic models. The first type are top-down models in which some or all agents are capable of understanding the whole picture and use this superior information to determine their optimal plans. The second type are bottom-up models in which all agents experience cognitive limitations. As a result, these agents are only capable of understanding and using small bits of information. These are models in which agents use simple rules of behavior. These models are not devoid of rationality. Agents in these models behave rationally in that they are willing to learn from their mistakes. These two types of models produce a radically different macroeconomic dynamics. I analyze these differences.DSGE-model, imperfect information, heuristics, animal spirits

Notes on Agents¡¯ Behavioral Rules Under Adaptive Learning and Studies of Monetary Policy

These notes try to clarify some discussions on the formulation of individual intertemporal behavior under adaptive learning in representative agent models. First, we discuss two suggested approaches and related issues in the context of a simple consumption-saving model. Second, we show that the analysis of learning in the NewKeynesian monetary policy model based on ¡°Euler equations¡± provides a consistent and valid approach.Euler equation, NewKeynesian, Adaptive learning.

Central Bank Communication and Expectations Stabilization

This paper analyzes the value of communication in the implementation of monetary policy. The central bank is uncertain about the current state of the economy. Households and firms are uncertain about the statistical properties of aggregate variables, including nominal interest rates, and must learn about their dynamics using historical data. Given these uncertainties, when the central bank implements optimal policy, the Taylor principle is not sufficient for macroeconomic stability: for reasonable parameterizations self-fulfilling expectations are possible. To mitigate this instability, three communication strategies are contemplated: i) communicating the precise details of the monetary policy -- that is, the variables and coefficients; ii) communicating only the variables on which monetary policy decisions are conditioned; and iii) communicating the inflation target. The first two strategies restore the Taylor principle as a sufficient condition for stabilizing expectations. In contrast, in economies with persistent shocks, communicating the inflation target fails to protect against expectations driven fluctuations. These results underscore the importance of communicating the systematic component of monetary policy strategy: announcing an inflation target is not enough to stabilize expectations -- one must also announce how this target will be achieved.

Expectations, Learning and Monetary Policy: An Overview of Recent Research

Expectations about the future are central for determination of current macroeconomic outcomes and the formulation of monetary policy. Recent literature has explored ways for supplementing the benchmark of rational expectations with explicit models of expectations formation that rely on econometric learning. Some apparently natural policy rules turn out to imply expectational instability of private agents?learning. We use the standard New Keynesian model to illustrate this problem and survey the key results about interest-rate rules that deliver both uniqueness and stability of equilibrium under econometric learning. We then consider some practical concerns such as measurement errors in private expectations, observability of variables and learning of structural parameters required for policy. We also discuss some recent applications including policy design under perpetual learning, estimated models with learning, recurrent hyperinflations, and macroeconomic policy to combat liquidity traps and deflation.Imperfect knowledge, learning, interest-rate setting, fluctuations, stability, determinacy.