Bounded Rationality in Macroeconomics

Fiscal and Monetary Stabilization Policy at the Zero Lower Bound: Consequences of Limited Foresight

(with Yinxi Xie)

Prepared for the Carnegie-Rochester-NYU Conference on “Central Banking in the 2020s and Beyond”

revised, August 2020
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Abstract: This paper reconsiders the degree to which macroeconomic stabilization is possible when the zero lower bound is a relevant constraint on the effectiveness of conventional monetary policy, under an assumption of bounded rationality. In particular, we reconsider the potential role of countercyclical fiscal transfers as a tool of stabilization policy. Because Ricardian Equivalence no longer holds when planning horizons are finite (even when relatively long), we find that fiscal transfers can be a powerful tool to reduce the contractionary impact of an increased financial wedge during a crisis, and can even make possible complete stabilization of both aggregate output and inflation under certain circumstances, despite the binding lower bound on interest rates. However, the power of such policies depends on the degree of monetary policy accommodation. We also show that a higher level of welfare is generally possible if both monetary and fiscal authorities commit themselves to history-dependent policies in the period after the financial disturbance that causes the lower bound to bind has dissipated.

Robustly Optimal Monetary Policy in a New Keynesian Model with Housing

(with Klaus Adam)

NBER Working Paper no. 26833, March 2020
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Abstract:  We analytically characterize optimal monetary policy for an augmented New Keynesian model with a housing sector. With rational private sector expectations about housing prices and inflation, optimal monetary policy can be characterized by a standard “target criterion” in terms of inflation and the output gap, that makes no reference to housing prices. If instead the policymaker is concerned with potential departures of private sector expectations from rational ones, and seeks a policy that is robust against such possible departures, then the optimal target criterion will also depend on housing prices. For empirically realistic cases, robustness requires
the central bank to “lean against” housing prices, i.e., to adopt a stance that is projected to undershoot (overshoot) its normal targets for inflation and the output gap following unexpected housing price increases (decreases). Notably, robustly optimal policy does not require that the central bank distinguish between “fundamental” and “non-fundamental” movements in housing prices.

Policy Options at the Zero Lower Bound When Foresight is Limited

Published,  AEA Papers and Proceedings, 2019
(with Yinxi Xie)
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Abstract:    We reconsider several monetary and fiscal policies that have been proposed as tools of stabilization policy when conventional interest-rate policy is constrained by the zero lower bound on interest rates, assuming that households and firms are capable of explicit forward planning over only a limited horizon. The predicted effects of all of the policies are somewhat different than under rational expectations, but credible announcements about future policy can still influence behavior, and there is if anything an even stronger case for pursuing systematic policies outside crisis periods in order to shape expectations during a crisis.

Monetary Policy Analysis When Planning Horizons Are Finite

Published,  AEA Papers and Proceedings, 2019
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Abstract: It is common to analyze the effects of alternative possible monetary policy commitments under the assumption of optimization under rational (or fully model-consistent) expectations. This implicitly assumes unrealistic cognitive abilities on the part of economic decision makers. The relevant question, however, is not whether the assumption can be literally correct, but how much it would matter to model decision making in a more realistic way. A model is proposed, based on the architecture of artificial intelligence programs for problems such as chess or go, in which decision makers look ahead only a finite distance into the future, and use a value function learned from experience to evaluate situations that may be reached after a finite sequence of actions by themselves and others. Conditions are discussed under which the predictions of a model with finite-horizon forward planning are similar to those of a rational expectations equilibrium, and under which they are instead quite different. The model is used to re-examine the consequences that should be expected from a central-bank commitment to maintain a fixed nominal interest rate for a substantial period of time. “Neo-Fisherian” predictions are shown to depend on using rational expectations equilibrium analysis under circumstances in which it should be expected to be unreliable.

Are Low Interest Rates Deflationary? A Paradox of Perfect Foresight Analysis

Published,  American Economic Review, 2019
(with Mariana Garcia-Schmidt)
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Additional material in September 2015 draft

Abstract: A prolonged period of extremely low nominal interest rates has not resulted in high inflation. This has led to increased interest in the “Neo-Fisherian” proposition according to which low nominal interest rates may themselves cause inflation to be lower. The fact that standard models of the effects of monetary policy have the property that perfect foresight equilibria in which the nominal interest rate remains low forever necessarily involve low inflation (at least eventually) might seem to support such a view. Here, however, we argue that such a conclusion depends on a misunderstanding of the circumstances under which it makes sense to predict the effects of a monetary policy commitment by calculating the perfect foresight equilibrium consistent with the policy. We propose an explicit cognitive process by which agents may form their expectations of future endogenous variables. Under some circumstances, such as a commitment to follow a Taylor rule, a perfect foresight equilibrium (PFE) can arise as a limiting case of our more general concept of reflective equilibrium, when the process of reflection is pursued sufficiently far. But we show that an announced intention to fix the nominal interest rate for a long enough period of time creates a situation in which reflective equilibrium need not resemble any PFE. In our view, this makes PFE predictions not plausible outcomes in the case of policies of the latter sort. According to the alternative approach that we recommend, a commitment to maintain a low nominal interest rate for longer should always be expansionary and inflationary, rather than causing deflation; but the effects of such “forward guidance” are likely, in the case of a long-horizon commitment, to be much less expansionary or inflationary than the usual PFE analysis would imply.

Macroeconomic Analysis without the Rational Expectations Hypothesis

Revised January 2013
Published in Annual Review of Economics, 2013
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Abstract: This paper reviews a variety of alternative approaches to the specification of the expectations of economic decisionmakers in dynamic models, and reconsiders familiar results in the theory of monetary and fiscal policy when one allows for departures from the hypothesis of rational expectations. The various approaches are all illustrated in the context of a common model, a log-linearized New Keynesian model in which both households and firms solve infinite-horizon decision problems; under the hypothesis of rational expectations, the model reduces to the standard “3-equation model” used in studies such as Clarida et al. (1999). The alternative approaches considered include rationalizable equilibrium dynamics (Guesnerie, 2008); restricted perceptions equilibria (Branch, 2004); decreasing-gain and constant-gain variants of least-squares learning dynamics (Evans and Honkapohja, 2001); rational belief equilibria (Kurz, 2012); and near-rational expectations equilibria (Woodford, 2010). Issues treated include Ricardian equivalence; the determinacy of equilibrium under alternative interest-rate rules; non-fundamental sources of aggregate instability; the tradeoff between inflation stabilization and output-gap stabilization; and the possibility of a “deflation trap.”

Robustly Optimal Monetary Policy in a Microfounded New Keynesian Model

Revised November 2011
(With Klaus Adam)
Published in Journal of Monetary Economics, 2012
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Abstract: We consider optimal monetary stabilization policy in a New Keynesian model with explicit microfoundations, when the central bank recognizes that private-sector expectations need not be precisely model-consistent, and wishes to choose a policy that will be as good as possible in the case of any beliefs close enough to model-consistency. We show how to characterize robustly optimal policy without restricting consideration a priori to a particular parametric family of candidate policy rules. We show that robustly optimal policy can be implemented through commitment to a target criterion involving only the paths of inflation and a suitably defined output gap, but that a concern for robustness requires greater resistance to surprise increases in inflation than would be considered optimal if one could count on the private sector to have “rational expectations.”

Robustly Optimal Monetary Policy with Near-Rational Expectations

revised August 2009
Published in American Economic Review, 2010
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Additional material in December 2006 draft.

Abstract: The paper considers optimal monetary stabilization policy in a forward looking model, when the central bank recognizes that private-sector expectations need not be precisely model-consistent, and wishes to choose a policy that will be as good as possible in the case of any beliefs that are close enough to model-consistency. It is found that commitment continues to be important for optimal policy, that the optimal long-run inflation target is unaffected by the degree of potential distortion of beliefs, and that optimal policy is even more history-dependent than if rational expectations are assumed.

Information-Constrained State-Dependent Pricing

Revised June 2009
Published in Journal of Monetary Economics, 2009
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Abstract: I present a generalization of the standard (full-information) model of state dependent pricing in which decisions about when to review a firm’s existing price must be made on the basis of imprecise awareness of current market conditions. The imperfect information is endogenized using a variant of the theory of “rational inattention” proposed by Sims (1998, 2003, 2006). This results in a one-parameter family of models, indexed by the cost of information, which nests both the standard state-dependent pricing model and the Calvo model of price adjustment as limiting cases (corresponding to a zero information cost and an unboundedly large information cost respectively). For intermediate levels of the information cost, the model is equivalent to a “generalized Ss model” with a continuous “adjustment hazard” of the kind proposed by Caballero and Engel (1993a, 1993b), but provides an economic motivation for the hazard function and very specific predictions about its form. For high enough levels of the information cost, the Calvo model of price-setting is found to be a reasonable approximation to the exact equilibrium dynamics, except in the case of (infrequent) large shocks. When the model is calibrated to match the frequency and size distribution of price changes observed in microeconomic data sets, prices are found to be much less flexible than in a full-information state-dependent pricing model, and only about 20 percent more flexible than under a Calvo model with the same average frequency of price adjustment.