# George W. EvansUniversity of Oregon | UO · Department of Economics

George W. Evans

PhD, UC Berkeley, 1980

## About

161

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Introduction

**Skills and Expertise**

## Publications

Publications (161)

The impact of finite forecasting horizons on price dynamics is examined in a standard infinite-horizon asset-pricing model. Our theoretical results link forecasting horizon inversely to expectational feedback, and predict a positive relationship between expectational feedback and various measures of asset-price volatility. We design a laboratory ex...

In a broad class of non-linear representative agent models, represented by a system of difference equations, we replace rational expectations with linear forecast models conditioning on a predetermined set of regressors. Within this framework, a restricted perceptions equilibrium (RPE) corresponds to a forecast rule that is optimal within that clas...

Stagnation and fiscal policy are examined in a nonlinear stochastic New‐Keynesian model with adaptive learning. There are three steady states. The steady state targeted by policy is locally but not globally stable under learning. A severe pessimistic expectations shock can trap the economy in a stagnation regime, underpinned by a low‐level steady s...

Using the bounded rationality implementation developed in Evans et al. (2021) , we consider unemployment dynamics driven by aggregate productivity shocks within a McCall-type labor-search model. We find that bounded rationality magnifies the impact effect of a decline in productivity on unemployment. Boundedly rational agents are overly pessimistic...

We consider boundedly-rational agents in McCall's model of intertemporal job search. Agents update over time their perception of the value of waiting for an additional job offer using value-function learning. A first-principles argument applied to a stationary environment demonstrates asymptotic convergence to fully optimal decision-making. In envi...

We demonstrate existence, and stability under adaptive learning, of restricted perceptions equilibria in a nonlinear cobweb model.

We introduce a new class of solutions to nonlinear forward-looking models called near-rational sunspot equilibria (NRSE). NRSE are natural nonlinear extensions of the usual sunspot equilibria associated with the linearized version of the economy, and are near-rational in that agents use the optimal linear forecasting model when forming expectations...

We conduct experiments with human subjects in a model with a positive production externality in which productivity is a nondecreasing function of the average level of employment of other firms. The model has three steady states and a sunspot equilibrium that fluctuates between the high and low steady states. Steady states are payoff ranked: low val...

The conventional policy perspective is that lowering the interest rate increases output and inflation in the short run, while maintaining inflation at a higher level requires a higher interest rate in the long run. In contrast, it has been argued that a Neo‐Fisherian policy of setting an interest‐rate peg at a fixed higher level will increase the i...

The robustness of stability under learning to observability of exogenous shocks is examined. Regardless of observability assumptions, the minimal state variable solution is robustly stable under learning provided the expectational feedback is not both positive and large, while the nonfundamental solution is never robustly stable. Overlapping genera...

Within the standard RBC model we examine issues of expectational coordination on the unique rational expectations equilibrium. We show the sensitivity of agents' plans and decisions to their short-run and long-run expectations is too great to trigger eductive coordination in a world of rational agents who are endowed with knowledge of the economic...

Using the standard real business cycle model with lump-sum taxes, we analyze the impact of fiscal policy when agents form expectations using adaptive learning rather than rational expectations (RE). The output multipliers for government purchases are significantly higher under learning, and fall within empirical bounds reported in the literature, w...

This paper studies long-run inflation targets and stability in an imper-fect information environment. When central banks set an inflation target that is not fully communicated, agents draw inferences about inflation from recent data and remain alert to structural change in their econometric model by forming expectations from a forecasting model tha...

Ronald Coase wrote four articles on the cobweb model, or more
specifically on the so-called pig cycle. The focus was on practical policy: the
claim by the UK Reorganization Commission for Pigs and Pig Products, in their
1932 Report, that government intervention was needed to stabilize prices in the
pig industry. However, these papers co-authored wi...

Expectations are central to the determination of macroeconomic variables. Since the 1970s, 'adaptive expectations' have been replaced by 'rational expectations' (RE), with expectations modeled as optimal forecasts. Some economic models exhibit multiple RE, giving an independent role for expectations. The learning approach goes beyond RE to ask whet...

A restricted-perceptions equilibrium exists in which risk-averse agents believe stock prices follow a random walk with a conditional variance that is self-fulfilling. When agents estimate risk, bubbles and crashes arise. These effects are stronger when agents allow for ARCH in excess returns.

Analytical expectational stability results are obtained for both Euler-equation and infinite-horizon adaptive learning in a simple stochastic growth model. The rational expectations equilibrium is stable under both types of learning, though there are important differences in the learning dynamics.

This chapter examines the central ideas about learning and bounded rationality for macroeconomics and finance. It first introduces the main methodological issues concerning expectation formation and learning before discussing the circumstances in which rational expectations may arise. It then reviews empirical work that applies learning to macroeco...

We examine global dynamics under infinite-horizon learning in New Keynesian models where the interest-rate rule is subject to the zero lower bound. As in Evans, Guse and Honkapohja (2008), the intended steady state is locally but not globally stable. Unstable deflationary paths emerge after large pessimistic shocks to expectations. For large expect...

Agents have two forecasting models, one consistent with the unique rational expectations equilibrium, another that assumes a time-varying parameter structure. When agents use Bayesian updating to choose between models in a self-referential system, we find that learning dynamics lead to selection of one of the two models. However, there are paramete...

Using the standard real business cycle model with lump-sum taxes, we analyze the impact of fiscal policy when agents form expectations using adaptive learning rather than rational expectations (RE). The output multipliers for government purchases are significantly higher under learning, and fall within empirical bounds reported in the literature (i...

A crucial challenge for economists is figuring out how people interpret the world and form expectations that will likely influence their economic activity. Inflation, asset prices, exchange rates, investment, and consumption are just some of the economic variables that are largely explained by expectations. Here George Evans and Seppo Honkapohja br...

Incorporating adaptive learning into macroeconomics requires assumptions about how agents incorporate their forecasts into their decision-making. We develop a theory of bounded rationality that we call finite-horizon learning. This approach generalizes the two existing benchmarks in the literature: Eulerequation learning, which assumes that consump...

What is the impact of surprise and anticipated policy changes when agents form expectations using adaptive learning rather than rational expectations? We examine this issue using the standard stochastic real business cycle model with lump-sum taxes. Agents combine knowledge about future policy with econometric forecasts of future wages and interest...

In Evans, Guse, and Honkapohja (2008) the intended steady state is locally but not globally stable under adaptive learning, and unstable deflationary paths can arise after large pessimistic shocks to expectations. In the current paper a modified model is presented that includes a locally stable stagnation regime as a possible outcome arising from l...

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 wit...

Within the standard RBC model we examine issues of expectational coordination on the unique rational expectations equilibrium. We show sensitivity of agents’ plans and decisions to their short‐run and long‐run expectations is too great to trigger eductive coordination in a world of rational agents who are endowed with knowledge of the economic stru...

Commitment in monetary policy leads to equilibria that are superior to those from optimal discretionary policies. A number of interest rate reaction functions and instrument rules have been proposed to implement or approximate commitment policy. We assess these optimal reaction functions and instrument rules in terms of whether they lead to an RE e...

In this paper we analyze a credit economy � la Kiyotaki and Moore [1997. Credit cycles. Journal of Political Economy 105, 211-248] enriched with learning dynamics, where both borrowers and lenders need to form expectations about the future price of the collateral. We find that under homogeneous learning, the MSV REE for this economy is E-stable and...

This paper shows that the Ricardian Equivalence proposition can continue to hold when expectations are not rational and are instead formed using adaptive learning rules. In temporary equilibrium, with given expectations, Ricardian Equivalence holds under the standard conditions for its validity under rational expectations. Furthermore, Ricardian Eq...

We study how the use of judgment or "add-factors" in forecasting may disturb the set of equilibrium outcomes when agents learn by using recursive methods. We isolate conditions under which new phenomena, which we call exuberance equilibria, can exist in a standard self-referential environment. Local indeterminacy is not a requirement for existence....

This article advocates a theory of expectation formation that incorporates many of the central motivations of behavioral finance theory while retaining much of the discipline of the rational expectations approach. We provide a framework in which agents, in an asset pricing model, underparameterize their forecasting model in a spirit similar to Hong...

We study the properties of the generalized stochastic gradient (GSG) learning in forward-looking models. GSG algorithms are a natural and convenient way to model learning when agents allow for parameter drift or robustness to parameter uncertainty in their beliefs. The conditions for convergence of GSG learning to a rational expectations equilibriu...

We consider optimal monetary policy in New Keynesian models with inertia due to lagged effects of inflation and output. We characterize the conditions for the unconditionally optimal equilibrium and compare them with those identifying optimality from the timeless perspective. Implementation of optimal policy is considered via construction of suitab...

Following the introduction of inflation targeting and related monetary strategies, target inflation seems to have fallen to relatively low rates, about 2 to 3 per cent in many countries. This implies that large adverse shocks might push the economy into periods of deflation. This was clearly a major concern in the United States during the 2001 rece...

This article considers the interaction of optimal monetary policy and agents’ beliefs. We assume that agents choose their information acquisition rate by minimising a loss function that depends on expected forecast errors and information costs. Endogenous inattention is a Nash equilibrium in the information processing rate. Although a decline of po...

We examine global economic dynamics under infinite-horizon learning in a New Keynesian model in which the interest-rate rule is subject to the zero lower bound. As in Evans, Guse and Honkapohja, European Economic Review (2008), we find that under normal monetary and fiscal policy the intended steady state is locally but not globally stable. Unstabl...

Expectations play a central role in modern macroeconomic theories. The econometric learning approach models economic agents as forming expectations by estimating and updating forecasting models in real time. The learning approach provides a stability test for rational expectations and a selection criterion in models with multiple equilibria. In add...

We study how the use of judgment or “add-factors” in macroeconomic forecasting may disturb the set of equilibrium outcomes when agents learn using recursive methods. We examine the possibility of a new phenomenon, which we call exuberance equilibria, in the New Keynesian monetary policy framework. Inclusion of judgment in forecasts can lead to self...

This paper demonstrates that an asset pricing model with least-squares learning can lead to bubbles and crashes as endogenous responses to the fundamentals driving asset prices. When agents are risk-averse they need to make forecasts of the conditional variance of a stock's return. Recursive updating of both the conditional variance and the expecte...

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...

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...

We consider the robust stability of a rational expectations equilibrium, which we define as stability under discounted (constant gain) least-squares learning, for a range of gain parameters. We find that for operational forms of policy rules, ie rules that do not depend on contemporaneous values of endogenous aggregate variables, many interest-rate...

This paper reports on the findings of Evans, Guse, and Honkapohja (2007) concerning the global economic dynamics under learning in a New Keynesian model in which the interest rate rule is subject to the zero lower bound. Under normal monetary and fiscal policy, the intended steady state is locally but not globally stable. Large pessimistic shocks t...

Expectations play a key role in macroeconomics. The assumption of rational expectations has been recently relaxed by explicit models of forecasting and model updating. Rational expectations can be assessed for stability under various types of learning, with least squares learning playing a prominent role. In addition to assessing the plausibility o...

We examine global economic dynamics under learning in a New Keynesian model in which the interest-rate rule is subject to the zero lower bound. Under normal monetary and fiscal policy, the intended steady state is locally but not globally stable. Large pessimistic shocks to expectations can lead to deflationary spirals with falling prices and falli...

The impact of anticipated policy changes when agents form expectations using adaptive learning rather than rational expectations is considered. Agents are assumed to combine limited structural knowledge with a standard adaptive learning rule. These issues are analyzed using two well-known set-ups, an endowment economy and the Ramsey model. In our s...

I modify the uniform-price auction rules in allowing the seller to ration bidders. This allows me to provide a strategic foundation for underpricing when the seller has an interest in ownership dispersion. Moreover, many of the so-called "collusive-seeming" equilibria disappear.

By endowing his agents with simple forecasting models, or representations, M. Woodford ("Learning to Believe in Sunspots," Econometrica 58, 277-307, 1990) found that finite state Markov sunspot equilibria may be stable under learning. We show that common factor representations generalize to all sunspot equilibria the representations used by Woodfor...

This paper identifies two channels through which the economy can generate endogenous inflation and output volatility, an empirical regularity, by introducing model uncertainty into a Lucas-type monetary model. The equilibrium path of inflation depends on agents' expectations and a vector of exogenous random variables. Following Branch and Evans (20...

We analyze a monetary model with flexible labor supply, cash-in-advance constraints, and seigniorage- and tax-financed government spending. If the intertemporal elasticity of substitution of labor is greater than one, both determinate and indeterminate steady states exist. If the elasticity is less than one, there is a unique steady state, which ca...

We present a new application of Samuelson's Correspondence Principle to the analysis of comparative dynamics in stochastic rational expectations models. Our version, which we call the E-correspondence principle, applies to rational expectations equilibria that are stable under least squares and closely related learning rules. With this technique it...

We investigate both the rational explosive inflation paths studied by McCallum (2001), and the classification of fiscal and monetary policies proposed by Leeper (1991), for stability under least squares (LS) learning of the rational expectations equilibria (REE). Our first result is that the explosive fiscalist REE is not locally stable under LS le...

We show that if policymakers compute the optimal unconstrained interest-rate rule within a Taylor-type class, they may be led to rules that generate indeterminacy and/or instability under learning. This problem is compounded by uncertainty about structural parameters since an optimal rule that is determinate and stable under learning for one calibr...

We consider a linear univariate rational expectations model, with a predetermined variable, and study existence and stability of solutions driven by an extraneous finite-state Markov process. We show that when the model is indeterminate there exists a new class of k-state dependent sunspot equilibria in addition to the k-state sunspot equilibria (k...

Under rational expectations and risk neutrality the linear projection of exchange-rate change on the forward premium has a unit coefficient. However, empirical estimates of this coefficient are significantly less than one and often negative. We show that replacing rational expectations by discounted least-squares (or “perpetual”) learning generates...

This paper develops an adaptive learning formulation of an extension to the Ball, Mankiw and Reis (2005) sticky information model that incorporates endogenous inattention. We show that, following an exogenous increase in the policymaker's preferences for price vs. output stability, the learning process can converge to a new equilibrium in which bot...

We introduce the concept of Misspecification Equilibrium to dynamic macroeconomics. Agents choose between a list of misspecified econometric models and base their selection on relative forecast performance. A Misspecification Equilibrium is a stochastic process in which agents forecast optimally given their choices, with forecast model parameters a...

Commitment in monetary policy leads to equilibria that are superior to those from optimal discretionary policies. A number of interest-rate reaction functions and instrument rules have been proposed to implement or approximate commitment policy. We assess these rules in terms of whether they lead to a rational expectations equilibrium that is both...

A striking implication of the replacement of adaptive expectations by rational expectations was the “Lucas critique,” which showed that expectation parameters, and endogenous variable dynamics, depend on policy parameters. We consider this issue from the vantage point of bounded rationality, where for transparency we model bounded rationality by me...

Earlier studies of the seigniorage inflation model have found that the high-inflation steady state is not stable under learning. We reconsider this issue and analyze the full set of solutions for the linearized model. Our main focus is on stationary hyperinflationary paths near the high-inflation steady state. These paths are shown to be stable und...

One measure of the health of the Social Security system is the difference between the market value of the trust fund and the present value of benefits accrued to date. How should present values be computed for this calculation in light of future uncertainties? We think it is important to use market value. Since claims on accrued benefits are not cu...

We examine local strong rationality (LSR) in multivariate models with both forward-looking expectations and predetermined variables. Given hypothetical common knowledge restrictions that the dynamics will be close to those of a specified minimal state variable solution, we obtain eductive stability conditions for the solution to be LSR. In the sadd...

We consider a linear stochastic univariate rational expectations model, with a predetermined variable, and provide alternative representations of stationary sunspot equilibria (SSEs). For a strict subset of the parameter space there exist SSEs that are locally stable under least-squares learning provided agents use a common factor representation fo...

We examine existence and stability under learning of sunspot equilibria in a New Keynesian model incorporating inertia. Indeterminacy remains prevalent, stable sunspots abound, and inertia in IS and aggregate supply (AS) relations do not significantly impact the policy region containing stable sunspots.

We compare the performance of alternative recursive forecasting models. A simple constant gain algorithm, used widely in the learning literature, both forecasts well out of sample and also provides the best fit to the Survey of Professional Forecasters.

We consider inflation and debt dynamics under a global interest rate rule when private agents forecast using adaptive learning. Given the zero lower bound on interest rates, active interest rate rules are known to imply the existence of a second, low-inflation steady state. Under learning the economy can slip below this low-inflation steady state a...

The rational expectations hypothesis swept through macroeconomics during the 1970s and permanently altered the landscape. It remains the prevailing paradigm in macroeconomics, and rational expectations is routinely used as the standard solution concept in both theoretical and applied macroeconomic modelling. The rational expectations hypothesis was...

We examine stability under learning of sunspot equilibria in Real Business Cycle type models with indeterminacies. Our analysis emphasizes the importance of examining alternative representations of sunspot solutions. A general bivariate reduced form contains parameter regions in which sunspots are stable under learning. However, for parameters rest...

"Nowhere does history indulge in repetitions so often or so uniformly as in Wall Street," observed legendary speculator Jesse Livermore. History tells us that periods of major technological innovation are typically accompanied by speculative bubbles as economic agents overreact to genuine advancements in productivity. Excessive run-ups in asset pri...

We consider the stability under adaptive learning of the complete set of solutions to the model when |β|>1. In addition to the fundamentals solution, the literature describes both finite-state Markov sunspot solutions and autoregressive solutions depending on an arbitrary martingale difference sequence. We clarify the relationships between these so...

Forward-looking monetary models with Taylor-type interest rate rules are known to generate indeterminacies, with a potential dependence on extraneous ‘sunspots,’ for some structural and policy parameters. We investigate the stability of these solutions under adaptive learning, focusing on ‘common factor’ or ‘resonance frequency’ representations in...

The title speaks for itself: This special issue focuses attention on dynamical models in which expectations matter and in which expectational coordination is not taken for granted. This is a subject that has generated a lot of research in the past 20 years; the sample of papers presented here is witness to the present activity and the ongoing progr...

We investigate local strong rationality (LSR) in a one-step-forward-looking univariate model with memory one. Eductive arguments are used to determine when common knowledge (CK) that the solution is near some perfect-foresight path is sufficient to trigger complete coordination on that path (i.e., the path is LSR). Coordination of expectations is s...

Using New Keynesian models, we compare Friedman's "k"-percent money supply rule to optimal interest rate setting, with respect to determinacy, stability under learning and optimality. First we review the recent literature: open-loop interest rate rules are subject to indeterminacy and instability problems, but a properly chosen expectations-based r...

A fundamentals based monetary policy rule, which would be the optimal monetary policy without commitment when private agents have perfectly rational expectations, is unstable if in fact these agents follow standard adaptive learning rules. This problem can be overcome if private expectations are observed and suitably incorporated into the policy ma...

We review the recent work on interest rate setting, which emphasizes the desirability of designing policy to ensure stability under learning. Appropriately designed expectations-based rules can yield optimal rational expectations (REs) equilibria that are both determinate and stable under learning. Some simple instrument rules and approximate targe...

Business cycles in different regions of the United States tend to synchronize. This study investigates the reasons behind this synchronization of business cycles and the consequent formation of a national business cycle. Trade between regions may not be strong enough for one region to "drive" business cycle fluctuations in another region. This stud...

We argue herein that there is a fundamental and an important difference between the market risk and the potential market risk in financial markets. We also argue that the spectrum of smooth Lyapunov exponents can be used in ([lambda],[sigma]2)-analysis, which is a method to measure and monitor these risks. The reason is that these exponents focus o...

"Nowhere does history indulge in repetitions so often or so uniformly as in Wall Street," observed legendary speculator Jesse Livermore. History tells us that periods of major technological innovation are typically accompanied by speculative bubbles as economic agents overreact to genuine advancements in productivity. Excessive run-ups in asset pri...

We develop a monetary model with flexible supply of labor, cash in advance constraints and government spending financed by seignorage. This model has two regimes. One regime is conventional with two steady states. The other regime has a unique steady state which can be determinate or indeterminate. In the latter case there exist sunspot equilibria...

We extend common factor analysis to a multi-dimensional setting by considering a bivariate reduced form consistent with many Real Business Cycle type models. We show how to obtain new representations of sunspots and find that there are parameter regions in which these sunspots are stable under learning. However, once the parameters are restricted t...

We consider a linear stochastic univariate rational expectations model, with a predetermined variable, and provide alternative representations of SSEs (stationary sunspot equilibria). For a strict subset of the parameter space there exist SSEs that are locally stable under least squares learning provided agents use a common factor representation fo...