interpreting economic time series this paper explores some of the implications for econometric practice of the principle that people s observed behavior will change when their constraints change in dynamic contexts a proper definition of people s constraints includes among them laws of motion that describe the evolution of the taxes they must pay and the prices of the goods that they buy and sell changes in agents perceptions of these laws of motion or constraints will in general produce changes in the schedules that describe the choices they make as a function of the information that they possess until very recently received dynamic econometric practice ignored this principle the practice of dynamic econometrics should be changed so that it is consistent with the principle that people s rules of choice are influenced by their constraints this is a substantial undertaking and involves major adjustments in the ways that we formulate estimate and simulate econometric models

contagion as a wealth effect financial contagion is described as a wealth effect in a continuous time model with two risky assets and three types of traders noise traders trade randomly in one market long term investors provide liquidity using a linear rule based on fundamentals convergence traders with logarithmic utility trade optimally in both markets asset price dynamics are endogenously determined numerically as functions of endogenous wealth and exogenous noise when convergence traders lose money they liquidate positions in both markets this creates contagion in that returns become more volatile and more correlated contagion reduces benefits from portfolio diversification and raises issues for risk management during the f inancial panic associated with the default of the russian government in august 1998 and the subsequent collapse of the hedge fund long term capital management numerous hedge funds banks and securities firms tried simultaneously to reduce exposures to a variety of financial instruments such as russian bonds brazilian stocks u s mortgages spreads between on therun and off the run government securities and spreads between swaps and u s treasuries although the fundamental values of these positions would appear to have little correlation during this financial crisis the asset prices in these markets exhibited the following common empirical pattern 1 financial intermediaries suffered losses as prices moved against their positions 2 market depth and liquidity decreased simultaneously in several markets 3 the volatility of prices increased simultaneously in several markets and

a two person dynamic equilibrium under ambiguity this paper describes a pure exchange continuous time economy with two heterogeneous agents and complete markets a novel feature of the economy is that agents perceive some security returns as ambiguous in the sense often attributed to frank knight the equilibrium is described completely in closed form after identifying agents as countries the model is applied to address the consumption home bias and equity home bias puzzles 2002 elsevier science b v all rights reserved jel classi cation d81 g11 g12 g15

methods for robust control robust control allows policymakers to formulate policies that guard against model misspecification the principal tools used to solve robust control problems are state space methods see hansen l p sargent t j 2008 robustness princeton university press giordani p soderlind p 2004 solution of macromodels with hansen sargent robust policies some extensions journal of economic dynamics and control 28 12 2367 2397 in this paper we show that the structural form methods developed by dennis 2007 optimal policy rules in rational expectations models new solution algorithms macroeconomic dynamics 11 1 31 55 to solve control problems with rational expectations can also be applied to robust control problems with the advantage that they bypass the task often onerous of having to express the reference model in state space form in addition we show how to implement two different timing assumptions with distinct implications for the robust policy and the economy we apply our methods to a new keynesian dynamic stochastic general equilibrium model and find that robustness has important effects on policy and the economy

using asset prices to measure the cost of business cycles we measure the cost of consumption fluctuations using an approach that does not require the specification of preferences and instead uses asset prices we measure the marginal cost of consumption fluctuations the per unit benefit of a marginal reduction in consumption fluctuations expressed as a percentage of lifetime consumption we find that the gains from eliminating all consumption uncertainty are very large however for consumption fluctuations corresponding to business cycle frequencies we estimate the marginal cost to be between 0 08 percent and 0 49 percent of lifetime consumption

consensus consumer and intertemporal asset pricing with heterogeneous beliefs le fichier attache est egalement edite dans les cahier de la chaire les particuliers face aux risques de l institut de finance de dauphine cahier n 7 mars 2007

agricultural price distortions trends and volatility past and prospective thanks are due to the australian research council the rural industries research and development corporation and the world bank for financial assistance

asymmetric information and rational expectations when is it right to be wrong abstract in this paper we examine the effects of private agents being less than fully rational in their expectations we examine this in the context of monetary policy where the central bank may have uncertain preferences either by choice or by necessity the new feature is that we allow the public to react in two different ways they either form rational expectations and internalize the uncertainty about the central bank s preferences in full or alternatively and if this process of internalization is costly it forms a best guess regarding those preferences this implies a certainty equivalence strategy applied to the preference parameters as those parameters enter the decisions non linearly a systematic error emerges we examine the magnitude of the resulting error in inflation and output following the assumption of certainty equivalence under all reasonable levels of uncertainty this error turns out to be small but involves trading a deflation bias against the cost of gathering the information needed for the full information rational expectations solution

uncertainty and risk in financial markets this paper considers a general equilibrium model in which the distinction between uncertainty and risk is formalized by assuming agents have incomplete preferences over statecontingent consumption bundles as in bewley 1986 without completeness individual decision making depends on a set of probability distributions over the state space a bundle is preferred to another if and only if it has larger expected utility for all probabilities in this set when preferences are complete this set is a singleton and the model reduces to standard expected utility in this setting we characterize pareto optima and equilibria and show that the presence of uncertainty generates robust indeterminacies in equilibrium prices and allocations for any specification of initial endowments we derive comparative statics results linking the degree of uncertainty with changes in equilibria despite the presence of robust indeterminacies we show that equilibrium prices and allocations vary continuously with underlying fundamentals equilibria in a standard risk economy are thus robust to adding small degrees of uncertainty finally we give conditions under which some assets are not traded due to uncertainty aversion

a dynamic structural model for stock return volatility and trading volume an examination is made of an adaptive beliefs model that is able to roughly reproduce the following features seen in the data 1 the autocorrelation functions of the volatility of returns and trading volume are positive with slowly decaying tails 2 the cross correlation function of volatility is approximately zero for squared returns with past and future volumes and is positive for squared returns with current volumes 3 abrupt changes in prices and returns occur that are hard to attach to news the last feature is obtained because the law of large numbers can fail in the large economy limit

equity premium and consumption sensitivity when the consumer investor allows for unfavorable circumstances abstract introducing one additional element due to possible misfortune to the return of each of two assets in the basic model of samuelson rev econom statist 51 1969 239 on optimum portfolio and consumption decisions this paper resolves both the excess equity premium and the excess consumption sensitivity puzzles this unified treatment provides a framework to study how important state variables will affect the change in aggregate consumption which is considered unpredictable in one formulation of the permanent income hypothesis the implications of the theory agree with empirical results reported here and elsewhere the theoretical framework appears to be simple and powerful as compared with alternative theories to explain the two puzzles

doubts or variability reinterpreting most of the market price of risk as a price of model uncertainty eradicates a link between asset prices and measures of the welfare costs of aggregate fluctuations that was proposed by hansen et al 1999 tallarini 2000 and alvarez and jermann 2004 prices of model uncertainty contain information about the benefits of removing model uncertainty not the consumption fluctuations that lucas 1987 2003 studied a max min expected utility theory lets us reinterpret tallarini s riskaversion parameter as measuring a representative consumer s doubts about the model specification we use model detection instead of risk aversion experiments to calibrate that parameter plausible values of detection error probabilities give prices of model uncertainty that approach the hansen and jagannathan 1991 bounds fixed detection error probabilities give rise to virtually identical asset prices as well as virtually identical costs of model uncertainty for tallarini s two models of consumption growth

a closed form solution for a model of precautionary saving this paper analyses life cycle consumption plans and distinguishes between temporal risk aversion and intertemporal substitution the results assume that felicity functions are quadratic and that income follows a linear model with normally distributed errors stochastic dynamic programming then yields closed loop linear decision rules certainty equivalence no longer holds but instead households play a min max strategy against nature one finds a rationale for precautionary saving and a larger sensitivity of changes in consumption to income innovations

learning under fear of floating in recent years a large fraction of economies overcame the fear of floating we study a model that describes the policy of a central bank uncertain about whether currency depreciations cause output to expand textbook model or contract balance sheet model we conclude that the movement away from fear of floating may not be explained by bayesian or robust policies when the private sector anticipates the central bank s policy and endogenously determines the model central banks may fall in a learning trap an increase in financial volatility provides an escape to such trap that replicates patterns in the data

would freeing up world trade reduce poverty and inequality the vexed role of agricultural distortions trade policy reforms in recent decades have sharply reduced the distortions that were harming agriculture in developing countries yet global trade in farm products continues to be far more distorted than trade in nonfarm goods those distortions reduce some forms of poverty and inequality but worsen others so the net effects are unclear without empirical modeling this paper summarizes a series of new economy wide global and national empirical studies that focus on the net effects of the remaining distortions to world merchandise trade on poverty and inequality globally and in various developing countries the global linkage model results suggest that removing those remaining distortions would reduce international inequality largely by boosting net farm incomes and raising real wages for unskilled workers in developing countries and would reduce the number of poor people worldwide by 3 percent the analysis based on the global trade analysis project model for a sample of 15 countries and nine stand alone national case studies all point to larger reductions in poverty especially if only the non poor are subjected to increased income taxation to compensate for the loss of trade tax revenue

discussion of robustness and pricing with uncertain growth hansen and sargent and a number of coauthors have recently initiated a research agenda that introduces the notion of robustness to model uncertainty or a concern with model misspecification into macroeconomics and finance methodologically they modify key techniques from the robust control literature in applied mathematics in order to allow for recursivity discounting and stochastic dynamics which are obvious ingredients of the conventional modeling paradigm in financial economics the fundamental idea behind robustness is that economic models are at best viewed as stylized approximations of reality rather than perfectly accurate descriptions thereof it is then natural to entertain the possibility that economic agents making decisions in these models share the concern for model misspecification that economists and econometricians routinely express when agents use a particular model as guidance in a dynamic decision problem and worry that this model might be misspecified one would expect them to insist on considering alternative models in order to obtain decision rules that not only work well when the particular baseline model is correct but that also perform reasonably well when the model is somewhat misspecified this is the sense in which the decision rule is designed to be robust the question of course is how agents go about considering alternative models and obtaining a robust decision rule given these alternative models in this article as in other work introducing robustness the agents are assumed to achieve robustness by considering a least favorable or worst case model that is similar to and statistically hard to distinguish from the baseline model worrying about a worst case distortion of the baseline model seems quite drastic first it should be emphasized that the least favorable model is endogenously selected from a set of models that are close to the baseline model where distance between models is measured by an entropy or likelihoodtype criterion and in accordance with a preference parameter that measures the strength of the preference for robustness 0 effectively the preference parameter 0 dictates how much confidence the decision maker has in the baseline model so that i indicates to what extent she is willing to consider 0

rules of thumb versus dynamic programming this paper studies decision making with rules of thumb in the context of dynamic decision problems and compares it to dynamic programming a rule is a fixed mapping from a subset of states into actions rules are compared by averaging over past experiences this can lead to favoring rules which are only applicable in good states correcting this good state bias requires solving the dynamic program we provide a generalframework and characterize the asymptotic properties we apply it to provide a candidate explanation for the sensitivity of consumption to transitory income jel eoo c63 c61 e21

four types of ignorance discussion this is a comment on hansen and sargent 2015 using a generalized one period setup i provide some intuition and perspective

aggregation over time and the inverse optimal predictor problem for adaptive expectations in continuous time this paper describes the continuous time stochastic process for money and inflation under which cagan s adaptive expectations model is optimal it then analyzes how data formed by sampling money and prices at discrete points in time would behave this abstract was borrowed from another version of this item

agents as empirical macroeconomists thomas j sargent s contribution to economics thomas j sargent has fundamentally changed and in the words of art rolnick who interviewed him in 2010 irrevocably transformed the field of macroeconomics whether as sole author as co author with collaborators as an author influenced by others or as a teacher of the profession influencing others this paper is about his contribution to our field the nobel memorial prize to thomas j sargent and christopher a sims has been awarded for the empirical research on cause and effect in the macroeconomy or more broadly for macroeconometrics one often likes to distinguish between theorists on the one hand and empiricists and econometricians on the other thomas j sargent holds a unique position in between a key theme in a large part of his work has been to put the agents in his model on equal footing with the econometrician who is observing data from the model i e to assume that agents are themselves empirical macroeconomists or macroeconometricians in this paper i use this theme to examine his work and his contributions to the study of economics

risk ambiguity and the exercise of employee stock options abstract we investigate the importance of ambiguity or knightian uncertainty in executives stock option exercise decisions we develop an empirical estimate of ambiguity and include it in regression models alongside the traditional measure of risk equity volatility we show that each variable has a significant effect on the timing of option exercises with volatility causing executives to hold options longer to preserve option value and ambiguity increasing the tendency for executives to exercise early

stochastic control for economic models past present and the paths ahead abstract on the 30th anniversary of a meeting between engineers and economists at princeton university to discuss the potential application of stochastic control methods to economics this paper provides a review of past present and paths ahead the events surrounding some of the key developments of the past are described along with a discussion of the present state of the research and of paths for future research the paper is structured around the primary methods for solving quadratic linear economic stochastic control models namely open loop classical control handcrafted feedback rules optimal feedback min max control optimal feedback rules with parameter uncertainty and dual control the paper also includes a discussion of software developments in economic stochastic control modeling

robustness information processing constraints and the current account in small open economies article i nfo in this paper we examine the effects of two types of induced uncertainty model uncertainty due to robust ness rb and state uncertainty due to finite information processing capacity called rational inattention or ri on consumption and the current account we show that the combination of rb and ri improves the model s predictions for i the contemporaneous correlation between the current account and income and ii the volatility and persistence of the current account in small open emerging and developed economies in addition we show that the two informational frictions improve the model s ability to match the impulse response of consumption to income and the relative volatility of consumption to income growth

the credibility revolution in empirical economics how better research design is taking the con out of econometrics since edward leamer s memorable 1983 paper let s take the con out of econometrics empirical microeconomics has experienced a credibility revolution while leamer s suggested remedy sensitivity analysis has played a role in this we argue that the primary engine driving improvement has been a focus on the quality of empirical research designs the advantages of a good research design are perhaps most easily apparent in research using random assignment we begin with an overview of leamer s 1983 critique and his proposed remedies we then turn to the key factors we see contributing to improved empirical work including the availability of more and better data along with advances in theoretical econometric understanding but especially the fact that research design has moved front and center in much of empirical micro we offer a brief digression into macroeconomics and industrial organization where progress by our lights is less dramatic although there is work in both fields that we find encouraging finally we discuss the view that the design pendulum has swung too far critics of design driven studies argue that in pursuit of clean and credible research designs researchers seek good answers instead of good questions we briefly respond to this concern which worries us little

robust control of forward looking models abstract this paper shows how to formulate and compute robust ramsey aka stackelberg plans for linear models with forward looking private agents the leader and the followers share a common approximating model and both have preferences for robust decision rules because both doubt the model since their preferences differ the leader s and followers decision rules are fragile to different misspecifications of the approximating model we define a stackelberg equilibrium with robust decision makers in which the leader and follower have different worst case models despite sharing a common approximating model to compute a stackelberg equilibrium we formulate a bellman equation that is associated with an artificial single agent robust control problem the artificial bellman equation contains a description of implementability constraints that include euler equations that describe the worst case analysis of the followers as an example the paper analyzes a model of a monopoly facing a competitive fringe

rational beliefs or distorted beliefs the equity premium puzzle and micro survey data 1 introductionsince shiller 1982 and mehra and prescott 1985 questioned why the gap between the rates of returns from stocks and bonds is so large the equity premium puzzle has attracted the attention of many economists the numerous explanations for the puzzle that have been put forth can be categorized into three approaches the first approach is to explain the puzzle under full rationality by introducing more complex utility functions epstein and zin 1989 and weil 1989 use a utility function that breaks the tight relation between the risk aversion coefficient and the elasticity of intertemporal substitution constantinides 1990 introduces the utility function with habit formation to the literature and campbell and cochrane 1999 succeed in explaining the equity premium puzzle and stock return predictability by making use of a particular variant of habit formation the second approach is to see the puzzle as being a result of distorted beliefs while maintaining the traditional power utility function rietz 1988 shows that the puzzle can be explained if consumers believe that a disastrous situation has a higher probability of arising than the historical data imply recently cecchetti lam and mark 2000 also succeeded in matching the first and second moments of the equity premium and the predictability of stock returns by assuming that the representative consumer with the traditional power utility function has distorted beliefs of a particular kind that lead him her to expect that both expansions and contractions end more quickly than the data suggest the third approach is to see the puzzle as being a result of market frictions such as borrowing constraints and short sale constraints heaton and lucas 1996 show the potential of this approach and luttmer 1999 estimates the magnitude of such frictions using the first order conditions from utility maximization however because of the success of campbell and cochrane 1999 and cecchetti lam and mark 2000 in explaining various aspects of the asset pricing phenomena including the equity premium puzzle this paper mainly focuses on an investigation of the first two approaches with the use of survey forecasts 1 in spite of the success of both approaches the puzzle has not yet been resolved because both approaches use completely different mechanisms to explain the puzzle we still do not know which one provides a better description of the cause of the puzzle in other words because the stylized facts in the financial market can be explained by both models it is hard for economists to judge which is the correct mechanism by looking at financial and consumption data 2 hence the main purpose of this paper is to derive different implications of consumers expectations from both models and to examine which implication is supported more through an investigation of the survey forecasts because campbell and cochrane s model retains rational expectations whereas cecchetti lam and mark s model is based on distorted beliefs the two models implications for survey forecasts will differ whereas campbell and cochrane 1999 would predict that survey forecasts are rational cecchetti lam and mark 2000 would claim that forecasts are excessively pessimistic over expansions and excessively optimistic over contractions using the livingston survey forecasts for the standard and poor s 500 index which is managed by the federal reserve bank of philadelphia this paper conducts a test of these implications to check whether the expected excess returns from the survey forecasts are rational a panel data model allowing a four dimensional structure for forecast errors individual bias business cycle effect aggregate shocks and idiosyncratic errors is analyzed 3the test results seem to support the model of cecchetti lam and mark 2000 the expected equity premium implied by the survey forecasts is on average lower than the actual realized equity premium during the sample period

the real bills doctrine versus the quantity theory a reconsideration two competing monetary policy prescriptions are analyzed within the context of overlapping generations models the real bills prescription is for unfettered private intermediation or central bank operations designed to produce the effects of such intermediation the quantity theory prescription in contrast is for restrictions on private intermediation designed to separate money from credit although our models are consistent with quantity theory predictions about money supply and price level behavior under these two policy prescriptions the models imply that the quantity theory prescription is not pareto optimal and the real bills prescription is

a theory of rational addiction we develop a theory of rational addiction in which rationality means a consistent plan to maximize utility over time strong addiction to a good requires a big effect of past consumption of the good on current consumption such powerful complementarities cause some steady states to be unstable they are an important part of our analysis because even small deviations from the consumption at an unstable steady state can lead to large cumulative rises over time in addictive consumption or to rapid falls in consumption to abstention our theory also implies that cold turkey is used to end strong addictions that addicts often go on binges that addicts respond more to permanent than to temporary changes in prices of addictive goods and that anxiety and tensions can precipitate an addiction

model misspecification and underdiversification in this paper we study intertemporal portfolio choice when an investor accounts explicitly for model misspecification we develop a framework that allows for ambiguity about not just the joint distribution of returns for all stocks in the portfolio but also for different levels of ambiguity for the marginal distribution of returns for any subset of these stocks we find that when the overall ambiguity about the joint distribution of returns is high then small differences in ambiguity for the marginal return distribution will result in a portfolio that is significantly underdiversified relative to the standard mean variance portfolio

saving and liquidity constraints this paper is concerned with the theory of saving when consumers are not permitted to borrow and with the ability of such a theory to account for some of the stylized facts of saving behavior the models presented in the paper seem to account for important aspects of reality that are not explained by traditional life cycle models copyright 1991 by the econometric society

humans environment and economies from vicious relationships to virtuous responsibility abstract the debates questioning the meaning of growth point to a need for a more holistic understanding of human beings and of the economic actor fundamental to economic theory and practice this contribution turns to virtue ethics in order to reframe the self in more reflexive relational and environmental terms we explore the significance of understanding humans sense of responsibility that is quintessentially relational and of their capacity and need to relate to nature as well as community and society we begin by reviewing the main arguments in the thriving debate in ecological economics around what the characteristics of the human being can contribute to implement an ecologically sustainable development our aim is then to draw a link between this debate and that of virtue ethics that leads to a different understanding of the human being of what can contribute to individual wellbeing and a good life responsibility we argue is not only a value but a virtue that enables individuals to find meaning in acting responsibly towards the environment emphasising the multiple benefits that arise from framing good lives in active terms we conclude reflecting on the challenges to and implications of our proposition for government institutions particularly education

precautionary saving and consumption smoothing across time and possibilities this paper examines how aversion to risk and aversion to intertemporal substitution determine the strength of the precautionary saving motive in a two period model with selden kreps porteus preferences for small risks we derive a measure of the strength of the precautionary saving motive which generalizes the concept of prudence introduced by kimball 1990b for large risks we show that decreasing absolute risk aversion guarantees that the precautionary saving motive is stronger than risk aversion regardless of the elasticity of intertemporal substitution holding risk preferences fixed the extent to which the precautionary saving motive is stronger than risk aversion increases with the elasticity of intertemporal substitution we derive sufficient conditions for a change in risk preferences alone to increase the strength of the precautionary saving motive and for the strength of the precautionary saving motive to decline with wealth within the class of constant elasticity of intertemporal substitution constant relative risk aversion utility functions these conditions are also necessary

money as a medium of exchange in an economy with artificially intelligent agents abstract we study the exchange economies of kiyotaki and wright 1989 in which agents must use a commodity or fiat money as a medium of exchange if trade is to occur our agents are artificially intelligent and are modeled as using classifier systems to make decisions in the assignment of credit within the classifier systems we introduce some innovations designed to study sequential decision problems in a multi agent environment for most economies that we have simulated trading and consumption patterns converge to a stationary nash equilibrium even if agents start with random rules in economies with multiple equilibria the only equilibrium that emerges in our simulations is the one in which goods with low storage costs play the role of medium of exchange i e the fundamental equilibrium of kiyotaki and wright

escaping nash inflation an ordinary differential equation ode gives the mean dynamics that govern the convergence to self confirming equilibria of self referential systems under discounted least squares learning another ode governs escape dynamics that recurrently propel away from a self confirming equilibrium in a model with a unique self confirming equilibrium the escape dynamics make the government discover too strong a version of the natural rate hypothesis the escape route dynamics cause recurrent outcomes close to the ramsey commitment inflation rate in a model with an adaptive government

interest on reserves abstract in a general equilibrium setting we study versions of the proposal to pay interest on reserves at the market rate we argue that the proposal makes the demand for total reserves indeterminate whether interest is paid on total reserves or on required reserves only one consequence is that tax financing of the proposal gives rise to a continuum of equilibria equilibria which differ in real returns and consumption allocations another consequence is that financing through earnings on the central bank s portfolio either gives rise to an equilibrium with a zero nominal interest rate or to no equilibrium

a model of commodity money abstract commodity money is modeled as one or two of the capital goods in a one consumption good and one or two capital good overlapping generations model among the topics addressed using versions of the model are i the nature of the inefficiency of commodity money ii the validity of quantity theory predictions for commodity money systems iii the circumstances under which one commodity emerges naturally as the commodity money iv the role of inside money money backed by private debt in commodity money systems and v the circumstances under which a government can choose the commodity to serve as the commodity money

convergence of least squares learning in environments with hidden state variables and private information we study the convergence of recursive least squares learning schemes in economic environments in which there is private information the presence of private information leads to the presence of hidden state variables from the viewpoint of particular agents by applying theorems of ljung we extend some of our earlier results to characterize conditions under which a system governed by leastsquares learning will eventually converge to a rational expectations equilibrium we apply insights from the learning results to formulate and compute the equilibrium of a version of townsend s model

a general equilibrium analysis of foreign exchange shortages in a developing economy an acute shortage of foreign exchange has been a recurring problem for many developing economies this paper reexamines the foreign exchange gap issue and the debate between structuralists and neoclassicists by providing a quantitative assessment of the role of different assumptions about the values of key trade elasticities it also seeks to complement the existing descriptive analysis of the consequences of alternative adjustment mechanisms with a quantitative analysis that indicates the relative importance of different behavioural assumptions and policy regimes the empirical analysis is based on a computable general equilibrium model which is walrasian in spirit and captures price mechanisms market interactions and structural interdependence in a non linear multisector framework the analysis lends support to the structuralist view that it is not sufficient to look at problems of adjustment only at the macroeconomic level

agricultural trade distortions during the global financial crisis the authors are grateful for financial support from the australian research council rural industries research and development corporation and world bank

ecological economics as a policy science rhetoric or commitment towards an improved decision making process on sustainability abstract with sustainability issues currently attracting increasing political and policy attention this paper examines the impact of the rise of ecological economics in the policy world and its potential influence on the decision making process this study emphasises that ecological economics development is coevolved with and modified to fit specific social economic political and cultural contexts as a policy science ecological economics is context sensitive and action oriented explaining why it is so and what to do about it has become imperative for ecological economists this paper attempts to address the questions such as what are the macroeconomic conditions and political processes that make the formulation and implementation of ecological economic policy possible how should this alternative social reality engage with the dominant decision making process does ecological economics provide the necessary means for prescribing policy measures to achieve sustainable development endeavouring to understand these dimensions of ecological economics has been a dynamic social process and understanding this complex process might provide an opportunity to bridge the divide between policy rhetoric and reality in practice rather than maintain the status quo in order to achieve an improved decision making process on sustainability it highlights the imperative to explicitly study the institutional setting through which sustainable development policy discourse is mediated

solutions to the crisis the green new deal degrowth and the solidarity economy alternatives to the capitalist growth economy from an ecofeminist economics perspective this article deals with three approaches conceived as alternative approaches to the capitalist growth economy the green new deal degrowth and the solidarity economy ecofeminist economics has much to offer to each of these approaches but these contributions remain as of yet unrealized the green new deal largely represents the green economy which holds economic success as contingent upon the ecological restructuring of industrial production the degrowth approach more fundamentally raises questions concerning the relationship between material prosperity and individual and social well being the principles of the solidarity economy involve the immediate implementation of the principles of self determination and cooperation none of these approaches takes into account the claims of ecofeminist economics and none of them clearly view gender equity as essential to economic change the three approaches are however deeply gendered in the sense that they are implicitly based on assumptions concerning women s labor in the sphere of social reproduction this article demonstrates how each approach can be improved upon by the integration of ecofeminist economic principles in order to achieve economic change that also meets claims for gender equity

the economic crisis from a neoclassical perspective abstract this paper assesses the 2007 2009 recession using neoclassical business cycle theory i find that the 2007 2009 u s recession differs substantially from other postwar u s recessions and also from the 2008 recession in other countries in that lower labor input accounts for virtually all of the decline in income and output in the united states while lower productivity accounts for much of other u s recessions and the 2007 2009 recession in other countries i also find that existing classes of models including financial market imperfections models do not explain the u s recession this is because the 2007 2009 recession is almost exclusively related to what appear to be labor market distortions that drive a wedge between the marginal product of labor and the marginal rate of substitution between consumption and leisure a topic about which current classes of financial imperfection models are largely silent i discuss future avenues for developing this class of models and i consider alterna

recovery rates uncertainty certainly matters abstract previous studies identify default rate as the main systematic determinant of bond recovery rates we revisit this paradigm by investigating the impact of another factor economic uncertainty based on a wide sample of american default issues and relying on beta regression models well suited for the bounded heteroskedastic and skewed sample of recovery rates we analyze the determinants of recovery rate distributions we find economic uncertainty to be of paramount importance as it proves to be the most important systematic determinant of recovery rate distributions significant for both their mean and dispersion by contrast default rate remains a key determinant of the dispersion of these distributions but not for their means considering this evidence is critical to the sound implementation of stochastic recovery rate models used by financial institutions for the computation of regulatory capital

the term structure of interest rates in a dsge model with recursive preferences abstract a dynamic stochastic general equilibrium dsge model in which households have epstein and zin recursive preferences is solved with perturbation the parameters governing preferences and technology are estimated by maximum likelihood using macroeconomic data and the term structure of interest rates the estimates imply a large risk aversion an elasticity of intertemporal substitution higher than one and substantial adjustment costs furthermore the paper identifies the tensions within the model by estimating it on subsets of these data the analysis concludes by pointing out potential extensions that may improve the model s fit

feminism ecology and the philosophy of economics abstract the contemporary discipline of economics pays little heed to either the natural environment or to the work of women a review of the literature on the historical development of western concepts of self and science shows that this is not coincidental rather than suggesting that ecological economics reinforce the identification of women with nature however feminist thought suggests that dualistic thinking about men and women humans and nature can be should be replaced with a fuller picture of human identity and knowledge

portfolio choices and asset prices the comparative statics of ambiguity aversion we investigate the comparative statics of more ambiguity aversion as defined by klibanoff marinacci and mukerji 2005 in the context of the static two asset portfolio problem it is not true in general that more ambiguity aversion reduces the demand for the uncertain asset we exhibit some sufficient conditions to guarantee that ceteris paribus an increase in ambiguity aversion reduces the demand for the ambiguous asset and raises the equity premium for example this is the case when the set of plausible distributions of returns can be ranked according to the monotone likelihood ratio order we also show how ambiguity aversion distorts the price kernel in the alternative portfolio problem with complete markets for contingent claims

precautionary savings and the permanent income hypothesis this paper derives the explicit solution of a dynamic stochastic optimal consumption problem for infinitely lived agents whose preferences exhibit in the presence of non diversifiable labour income uncertainty a constant elasticity of intertemporal substitution and constant absolute risk aversion the constancy of the elasticity of intertemporal substitution which implies that marginal utility at zero consumption is infinite guarantees that the non negativity constraint on consumption is never binding along the optimal path the assumption of constant absolute risk aversion allows an explicit computation of human wealth and provides a simple representation of the precautionary savings motive

robustly strategic consumption portfolio rules with informational frictions this paper provides a tractable continuous time constant absolute risk aversion gaussian framework to explore how the interactions of fundamental uncertainty model uncertainty due to a preference for robustness and state uncertainty due to information processing constraints rational inattention affect strategic consumption portfolio rules and precautionary savings in the presence of uninsurable labor income specifically after solving the model explicitly i compute and compare the elasticities of strategic asset allocation and precautionary savings to risk aversion robustness and inattention furthermore for plausibly estimated and calibrated model parameters i quantitatively analyze how the interactions of model uncertainty and state uncertainty affect the optimal share invested in the risky asset and show that they can provide a potential explanation for the observed stockholding behavior of households with different education and income levels this paper was accepted by neng wang finance

between a rock and a soft place ecological and feminist economics in policy debates abstract the field of ecological economics includes both economic analysis on the one hand and discussions of normative values and visions for society on the other using feminist insights into cultural beliefs about the relative hardness and softness of these two sides this essay discusses how ecological economists can use this unique between space in order to better inform policy the current crisis of global climate change it is argued requires that economists move beyond modeling and measurement while ecological thinkers need to re examine beliefs about markets and profit

learning and asset prices under ambiguous information we propose a new modeling framework to study the asset pricing implications of learning under ambiguity aversion in a continuous time partial information lucas economy we characterize analytically equilibrium equity returns and make the following observations first learning under ambiguity aversion implies an equilibrium discount for ambiguity if and only if relative risk aversion is below one or equivalently the elasticity of intertemporal substitution eis is above one in this case ambiguity aversion increases conditional equity premia and volatilities second equilibrium interest rates are lower irrespective of risk aversion third no time invariant relation between excess returns and conditional variances exists therefore estimated relations between excess returns and equity conditional variances are highly time varying and have an indeterminate sign fourth estimates of the eis based on standard euler equations for equity returns are strongly downward biased in a setting of learning and ambiguity aversion therefore an eis well above one can be consistent with estimates of eis well below one fifth ambiguity does not resolve asymptotically finally using realistic model parameters we show that a low risk aversion and a moderate amount of ambiguity are consistent with the equity premium the low interest rate and the excess volatility puzzles

on the relation between robust and bayesian decision making abstract this paper compares bayesian decision theory with robust decision theory where the decision maker optimizes with respect to the worst state realization for a class of robust decision problems there exists a sequence of bayesian decision problems whose solution converges towards the robust solution it is shown that the limiting bayesian problem displays infinite risk aversion and that decisions are insensitive robust to the precise assignment of prior probabilities this holds independently of whether the preference for robustness is global or restricted to local perturbations around some reference model

on the welfare costs of business cycle fluctuations and economic growth variation in the 20th century and beyond lucas 1987 has shown a surprising result in business cycle research the welfare cost of business cycles are very small our paper has several original contributions first in computing welfare costs we propose a novel setup that separates the eects of uncertainty stemming from business cycle uctuations and economic growth variation second we extend the sample from which to compute the moments of consumption the whole of the literature chose primarily to we gratefully acknowledge the comments of caio almeida carlos e da costa robert f engle pedro c ferreira antonio fiorencio rodolfo manuelli samuel pessoa and octavio tourinho on this or on earlier versions of this paper all errors are ours we thank cnpq brazil faperj and inct for nancial support y corresponding author

agricultural incentives in developing countries measuring the effect of sectoral and economywide policies the impact of sector specific direct and economywide indirect policies on agricultural incentives for 18 developing countries for the period 1975 84 are estimated the direct effect is measured by the proportional difference between the producer price and the border price adjusting for distribution storage transport and other marketing costs the indirect effect has two components 1 the impact of the unsustainable portion of the current account deficit and of industrial protection policies on the real exchange rate and thus on the price of agricultural commodities relative to nonagricultural nontradables and 2 the impact of industrial protection policies on the relative price of agricultural commodities to that of nonagricultural tradable goods the authors found that a in almost all cases the direct effect is equivalent to a tax on exportable goods and to a subsidy for importables b the indirect effect also taxes agriculture and dominates the direct effect and c the direct policies for both importables and exportables stabilize domestic producer prices

benefits from u s monetary policy experimentation in the days of samuelson and solow and lucas a policy maker knows two models of ination unemplo yment dynamics one implies an exploitable trade o the other does not the policy maker s prior probability over the two models is part of his state vector bayes law converts the prior probability into a posterior probability at each date and gives the policy maker an incentive to experiment for two models calibrated to u s data through the early 1960s we isolate the component of government policy that is due to experimentation by comparing the outcomes from two bellman equations the rst of which experiments and learns the second of which learns but doesn t experiment we interpret the second as an anticipated utility model and study how well its outcomes approximate those from the experiment and learn bellman equation the approximation is good for our calibrations the benets from purposeful experimentation are small

how robustness can lower the cost of discretion model uncertainty has the potential to change importantly how monetary policy is conducted making it an issue that central banks cannot ignore using a standard new keynesian business cycle model this paper analyzes the behavior of a central bank that conducts policy under discretion while fearing that its model is misspecified the main results are as follows first policy performance can be improved if the discretionary central bank implements a robust policy this important result is obtained because the central bank s desire for robustness directs it to assertively stabilize inflation thereby mitigating the stabilization bias associated with discretionary policymaking second the central bank s fear of model misspecification leads it to forecast future outcomes under the belief that inflation in particular will be persistent and have large unconditional variance raising the probability of extreme outcomes private agents however anticipating the policy response make decisions under the belief that inflation will be more closely stabilized that is more tightly distributed than under rational expectations finally as a technical contribution the paper shows how to solve with robustness an important class of linear quadratic decision problems

on the ideological foundations of environmental policy abstract this paper is an investigation into the philosophies of science inherent in the development of two schools of thought in environmental economics neoclassical and steady state analysis it attempts to gain clearer insight into the direction of inquiry and the policy options of each by contrasting their perspective metaeconomic structures the sets of first principles shaping theoretical development the ontology of steady state analysis while accepting the general principle of rationality differs from neoclassicism by including the ecological interaction of people with nature as an element of spicies being the cosmology of the two schools differs in the steady statists take the laws of thermodynamics and the principle of biospheric assimilation of first principles questions of absolute scarcity take primacy over the neoclassical focus on problems of relative scarcity in policy analysis consequently steady state theorists view the environment problem in its global dimensions over a longer time continuum the result is that steady state policy prescriptions are not necessarily market bound and may transcend the intstitutional arrangements common in western capitalist societies

historical roots for ecological economics biophysical versus allocative approaches abstract a number of economists today are aware that the results of their science are more or less at variance with concrete fact and are alive to the necessity of perfecting it they go wrong rather in their choice of means to that end they try obstinately to get from their science alone the materials they know are needed for a closer approximation to fact whereas they should resort to other sciences and go into them thoroughly not just incidentally for their bearing on the given economic problem until economic science is much farther advanced economic principles are less important to the economists than the reciprocal bearings of the results of economics and the results of the other social sciences many economists are paying no attention to such interrelations for mastery of them is a long and fatiguing task requiring an extensive knowledge of facts whereas anyone with a little imagination a pen and a few reams of paper can relieve himself of a chat on principles pareto 1935 para 2022

export restrictions and price insulation during commodity price booms for individual countries variable trade barriers can be used to reduce the volatility of domestic relative to world prices if this is done by countries accounting for a large share of the market its effect is offset by increases in world price volatility this study shows the nature of the resulting collective action problem with the policy being ineffective on average in stabilizing domestic prices while increasing the volatility of the income transfers from terms of trade changes a simple approach to assessing the contribution of insulation to the price increases is developed and used with new estimates of agricultural distortions to assess its contribution to the price spikes in 1972 74 and 2006 08 for rice and wheat the analysis suggests that 45 percent of the increase in rice prices in 2006 08 and 30 percent of the increase in wheat prices was due to insulating behavior one sign of progress since 1972 74 was a substantial reduction in the extent of price insulating behavior by the industrial countries this provides little stabilizing benefit in the rice market because countries not classifying themselves at the world trade organization as developing account for only 3 percent of world rice consumption but it does offer some benefit for the wheat market where non developing countries account for 27 percent of consumption

the sensitivity of tests of the intertemporal allocation of consumption to near rational alternatives suppose a consumer sets consumption equal to income each period rather than following the optimal permanent income decision rule how much utility does he lose this paper finds that the answer is typically less than 10 cents 1 per quarter in environments specified by popular tests on aggregate data it includes calculations of the costs of excess sensitivity and excess smoothness to income and interest rate changes and the costs of ignoring information it concludes that the theory does not make predictions for aggregate tests that are robust to small costs such as information or transactions copyright 1989 by american economic association

robust permanent income and pricing i suppose there exists an extremely powerful and if i may so speak malignant being whose whole endeavours are directed toward deceiving me rene descartes meditations ii 1

a robust hansen sargent prediction formula this paper derives a formula for the optimal forecast of a discounted sum of future values of a random variable where optimal is defined in terms of the minimized h norm of the forecast error this problem reflects a preference for robustness in the presence of unstructured model uncertainty the paper shows that revisions of a robust forecast are more sensitive to new information and discusses the relevance of this result to previous findings of excess sensitivity of consumption and asset prices to new information 2001 elsevier science b v all rights reserved

cagan s model of hyperinflation under rational expectations this paper studies p cagan s model of the german hyperinflation under the hypothesis that adaptive expectations are rational it shows that inference about the key money demand elasticity parameter a is very senstitive to the specification of the dynamic interaction of the unobserved money demand shock with prices and money in particular if t j sargent s 1977 specification is modified then his basic conclusions are overturned identification of a does not require prior knowledge about the covariance of unobserved shock terms and d ata on the german hyperinflation imply a sharp not loose estimate of a which is of plausible magnitude finally informal tests indicate that modifying sargent s specification gives rise to improved model fit copyright 1987 by economics department of the university of pennsylvania and the osaka university institute of social and economic research association

a short note on updating the grilli and yang commodity price index the grilli and yang commodity price index is one of the most widely used commodity price series in the applied economics literature this note provides some practical advice on updating this data series by listing the base period index values identifying relevant data sources and describing a method for computing subindex weights in 1988 enzo grilli and maw cheng yang published their seminal article on the long run development of an index of 24 primary commodity prices gycpi deflated by an index of manufactured goods unit values the sample of average annual primary commodity prices covers about 54 percent of the primary commodity trade in the index reference period 1977 79 the deflators considered for manufacturing prices were the u s manufacturing price index usmpi and the manufacturing unit value index muv 1widely used and discussed the grilli and yang data set has been extended by a number of researchers the data have been employed in a variety of contexts in later studies thus the gycpi data continue to enjoy wide popularity in their own right and as a benchmark for new approaches to empirical studies

disasterization a simple way to fix the asset pricing properties of macroeconomic models a central difficulty in economics is to create a model with both good business cycle properties and asset pricing properties i show how to solve this difficulty by a simple portable modeling device the disasterization of models take an economy with good business cycle properties and create a new disasterized economy which is essentially identical to the original one except that disasters can destroy part of the capital stock and productivity in such a disasterized economy asset prices exhibit high and volatile risk premia but macro variables remain unchanged perturbations of this benchmark allow for feedback from finance to macro

robust control informational frictions and international consumption correlations abstract in this paper we examine the effects of model misspecification robustness or rb on international consumption correlations in an otherwise standard small open economy model with endogenous capital accumulation we show that in the presence of capital mobility in financial markets rb lowers the international consumption correlations by generating heterogeneous responses of consumption to productivity shocks across countries facing different macroeconomic uncertainty in addition we show that rb can also improve the model s predictions in three other moments of consumption dynamics the relative volatility of consumption to income the persistence of consumption and the correlation between consumption and output after calibrating the rb parameter using the detection error probabilities we show that the model can explain the observed international consumption correlations as well as the other consumption moments quantitatively finally we show that the main conclusions of our benchmark model do not change in an extension in which the agent cannot observe the state perfectly due to finite information processing capacity

induced uncertainty market price of risk and the dynamics of consumption and wealth abstract in this paper we examine the implications of model uncertainty or robustness rb for consumption and saving and the market price of uncertainty under limited information processing capacity rational inattention or ri first we show that ri by itself creates an additional demand for robustness that leads to higher induced uncertainty facing consumers second if we allow capacity to be elastic rb increases the optimal level of attention third we explore how the induced uncertainty composed of i model uncertainty due to rb and ii state uncertainty due to ri affects consumption and wealth dynamics the market price of uncertainty and the welfare losses due to incomplete information we find that induced uncertainty can better explain the observed consumption income volatility and market price of uncertainty low attention increases the effect of model misspecification