can learning affect exchange rate behavior the case of the dollar in the early 1980 s this paper demonstrates that a change in parameters of the money market that is not immediately understood will affect the behavior of exchange rate forecast errors while the market is learning the analysis is applied to the behavior of u s dollar german mark forecast errors during the early 1980 s when the market appeared to systematically underpredict the strength of the dollar consistent with this observation empirical estimates of implied forecast errors based upon bayesian learning suggest that forecast errors would have been on average negative during the period as the market came to realize the increase in u s money demand

solving exchange rate puzzles with neither sticky prices nor trade costs we present a simple framework in which both the exchange rates disconnect and forward bias puzzles are simultaneously resolved the flexible price two country monetary model is extended to include a consumption externality with habit persistence habit persistence is modeled using campbell cochrane preferences with deep habits along the lines of the work of ravn schmitt grohe and uribe by deep habits we mean habits defined over goods rather than countries the model is simulated using the artificial economy methodology it offers a neo classical explanation of the meese rogoff puzzle and mimics the failure of fundamentals to explain nominal exchange rates in a linear setting finally the model naturally generates the negative slope in the standard forward market regression

learning and control in a changing economic environment abstract in this paper we investigate optimal bayesian learning and control with lagged dependent variables and time varying unknown parameters we assess both the performance of alternative decision rules as in the computationally oriented dual control literature as well as the dynamics of learning and convergence of beliefs as in the more theoretically oriented bayesian learning literature our numerical results indicate that the optimal decision rule involves a noticeable degree of experimentation for moderate to large levels of uncertainty in most situations though the optimal rule will remain less activist than a certainty equivalent rule and induce gradualism exceptions occur when the process to be controlled is near the deterministic steady state in this situation we find that the decision maker will repeatedly undertake costly experiments the extent of optimal experimentation is lower if the unknown parameter is perceived to vary over time in contrast to the fixed parameter case however parameter uncertainty is continually renewed and the incentive to experiment never ceases

predictability in financial markets what do survey expectations tell us abstract there is widespread evidence of excess return predictability in financial markets for the foreign exchange market a number of studies have documented that the predictability of excess returns is closely related to the predictability of expectational errors of excess returns in this paper we investigate the link between the predictability of excess returns and expectational errors in a much broader set of financial markets using data on survey expectations of market participants in the stock market the foreign exchange market the bond market and money markets in various countries the results are striking first in markets where there is significant excess return predictability expectational errors of excess returns are predictable as well with the same sign and often even with similar magnitude this is the case for foreign exchange stock and bond markets second in the only market where excess returns are generally not predictable the money market expectational errors are not predictable either these findings suggest that an explanation for the predictability of excess returns must be closely linked to an explanation for the predictability of expectational errors

stabilization theory and policy 50 years after the phillips curve this paper discusses the impact of a w h phillips seminal work in macroeconomic stabilization policy on subsequent developments in that field we begin by reviewing the various stabilization rules adopted by phillips and show how these relate to optimal stabilization rules that emerge from linear quadratic optimization problems most of the early st abilization literature was associated with backward looking variables the development of rational expectations in the 1960 s and 1970 s posed a challenge for stabilization policy this arose from the role of forward looking inflationary expectations in the phillips curve and the effect this had on the design of optimal stabilization rules through issues such as the lucas critique and the time consistency of policy we also briefly comment on a long standing debate pertaining to the merits of fixed policy rules versus discretionary or optimal policy the latter part of the paper discusses some of the more contemporary aspects of stabilization policy thereby serving to illustrate the durability of phillips contributions

cost uncertainty and unilateral abatement unilateral abatement is sometimes advocated in order to set a good example that will make other countries follow the aim of this paper is to investigate whether existence of correlated cost uncertainty provides an incentive for a country to undertake unilateral abatement the theoretical model is driven by two main mechanisms first a learning effect as the follower country might reduce its risk premium as it can observe the cost level in the leader country second there is the public good effect i e the marginal benefit of abatement declines when abatement is a public good and other countries contribute to pollution reductions results shows that unilateral abatement would be efficient in reducing uncertainty about the unit costs of abatement if a country with low cost uncertainty would undertake abatement first while a country with initially high cost uncertainty would follow however countries may prefer to act simultaneously because of the larger uncertainties that are inherent in a sequential game

coupled economic ecological systems with slow and fast dynamics modelling and analysis method the purpose of this article is to contribute to the exploration of non convex dynamics in coupled human nature systems we study welfare issues associated with the management of a human nature complex adaptive system with a threshold and a stochastic driver we exemplify with a specific system where we link changes in the number and diversity of birds to the abundance of a pest insects that causes damages to goods and services valuable to human beings we present a method that simplifies the analysis and helps us discuss different management models that combine direct and indirect controls of the pest this allows us to show that 1 the choice of control method depends in a highly non linear way on biodiversity characteristics and 2 the socially optimal outcome may not be reachable using price instruments hence the price vs quantity debate needs to be revisited using a complex adaptive system lens

carry trades order flow and the forward bias puzzle we investigate the relation between foreign exchange fx order flow and the forward bias we outline a decomposition of the forward bias according to which a negative correlation between interest rate differentials and order flow creates a time varying risk premium consistent with that bias using 10 years of data on fx order flow we find that more than half of the forward bias is accounted for by order flow with the rest being explained by expectational errors we also find that carry trading increases currency crash risk in that order flow generates negative skewness in fx returns

differences in beliefs and currency risk premiums this paper studies the importance of heterogeneous beliefs for the dynamics of asset prices we focus on currency markets where the absence of short selling constraints allows us to perform sharper tests of theoretical predictions using a unique data set with detailed information on foreign exchange forecasts we construct an empirical proxy for differences in beliefs we show that this proxy has a strong effect on the implied volatility of currency options beyond the volatility of macroeconomic fundamentals we document that differences in beliefs impact also on the shape of the implied volatility smile on the volatility risk premiums and on future currency returns

an empirical study of portfolio balance and information effects of order flow on exchange rates abstract we propose a simple structural model of exchange rate determination which is inspired by the analytical framework recently forward by bacchetta and van wincoop 2006 and allows us to disentangle the portfolio balance and information effects of order flow on exchange rates we estimate this model employing an innovative transaction data set that covers all indirect foreign exchange transactions completed in the usd eur market via ebs and reuters between august 2000 and january 2001 our results indicate that the strong contemporaneous correlation between order flow and exchange rates is largely due to portfolio balance effects this result also appears to carry through the four fx intervention events that appear in our sample

intraday patterns in fx returns and order flow using a comprehensive high frequency foreign exchange dataset we present evidence of time of day effects in foreign exchange returns through a significant tendency for currencies to depreciate during local trading hours we confirm this pattern across a range of currencies and time zones we also find that this pattern is reflected in order flow and suggest that both patterns relate to the tendency of market participants to be net purchasers of foreign exchange in their own trading hours data from a single market maker appears to corroborate that interpretation

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

risk uncertainty and exchange rates this paper is motivated by two facts failure of log linear empirical exchange rate models of the 1970 s and the observed variability of risk premiums in the forward market rational maximizing models predict that changes in conditional variances of monetary policies government spendings and income growths affect risk premiums and induce conditional volatility of exchange rates i examine theoretically how changes in these exogenous conditional variances affect the level of the current exchange rate and attempt to quantify the extent that this channel explains exchange rate volatility using autoregressive conditional heteroscedastic models

threshold effects and incentives for the conservation of biodiversity biological diversity is a central component of the stock of natural capital on which all economic development is based other things being equal loss of biologically diversity implies loss of development potential and its conservation through sustainable use or outright protection implies the protection of that potential one characteristics of biodiversity loss of especial importance is that biodiversity loss more than any other current environmental problem is associated with ecological threshold effects the paper explores the implication of this characteristics for the properties of a biodiversity conservation strategy

caution and probing in a macroeconomic model abstract this paper reports on the application of an adaptive dual control technique to a small macroeconometric model of the u s economy both monetary and fiscal policy variables are used in the model the experiments find that probing and active learning will occur in small macroeconometric models but that unrealistically high terminal period penalties on state deviations are required before it appears

the implications of first order risk aversion for asset market risk premiums abstract in an effort to explain simultaneously the excess return predictability observed in equity bond and foreign exchange markets we incorporate preferences exhibiting first order risk aversion into a general equilibrium two country monetary model when we calibrate the model to us and japanese data we find that first order risk aversion substantially increases excess return predictability however this increased predictability is insufficient to match the data we conclude that the observed patterns of excess return predictability are unlikely to be explained purely by time varying risk premiums generated by highly risk averse agents in a complete markets economy

the economics of dead zones linking externalities from the land to their consequences in the sea the purpose of this review and analysis is to provide a basic understanding of the issues related to worldwide hypoxic zones and the range of economic questions sorely in need of answers we begin by describing the causes and extent of hypoxic zones worldwide followed by a review of the evidence concerning ecological effects of the condition and impacts on ecosystem services we describe what is known about abatement options and cost effective policy design before turning to an analysis of the large seasonally recurring hypoxic zone in the gulf of mexico we advance the understanding of this major ecological issue by estimating the relationship between pollutants nutrients and the areal extent of the hypoxic zone this production function relationship suggests that both instantaneous and legacy contributions of nutrients contribute to annual predictions of the size of the zone highlighting concerns that ecologists have raised about lags in the recovery of the system and affirms the importance of multiple nutrients as target pollutants we conclude with a discussion of critical research needs to provide input to policy formation

on the biasedness of forward foreign exchange rates irrationality or risk premia in this article the authors reconsider the k a froot and j a frankel 1989 results on the sources of forward discount bias they question the economic validity of some estimation restrictions that they impose and thus are led to question some of their results the authors employ a new exchange rate survey database that includes european monetary system currencies and use univariate and pooling estimation techniques that impose fewer restrictions than those of froot and frankel to test their hypotheses they find that the bias in the forward discount is attributable to both the failure of rational expectations and the existence of time varying risk premia copyright 1994 by university of chicago press

optimal pricing of environmental and natural resource use with stock externalities abstract underlying some of the most pressing environmental problems are the interlinked resource and environmental stock externalities with threshold effects using a simple dynamic model it is shown how in the face of such externalities the static market based policy instruments such as pigouvian taxes should be modified it is shown that even if for an initial period there is going to be no pollution stock damage the optimal policy still requires that abatement begins immediately and at increasing rates simulation of the model for the case of fossil fuel burning and the consequent global warming shows that the optimal carbon tax and therefore the optimal control strategy is particularly sensitive to changes in the marginal abatement cost and the level of fossil fuel demand policy simulations contrast the optimal control policy with and estimate the welfare losses from alternative policies deriving from arbitrary tax paths the latter include i a no tax policy ii a constant carbon tax rate iii the european community s proposed carbon tax path and iv a delayed optimal tax path

changing beliefs and systematic rational forecast errors with evidence from foreign exchange this paper addresses a new interpretation to the appearance in the early 1980s of systematic errors in forecasting the dollar exchange rate following a change in the process of a fundamental variable market participants revise their beliefs about the process using bayes rule since the market does not immediately recognize the change forecast errors are on average wrong during a period when the market is rationally learning for conservative parameter values the learning behavior of the dollar exchange rate in the early 1980s appears consistent with about half of the dollar s underprediction implied by the forward market copyright 1989 by american economic association

anomalies foreign exchange most all behavior can be explained by assuming that agents have stable well defined preferences and make rational choices consistent with those preferences in markets that eventually clear an empirical result qualifies as an anomaly if it is difficult to rationalize or if implausible assumptions are necessary to explain it within the paradigm this column will present a series of such anomalies readers are invited to suggest topics for future columns by sending a note with some reference to or better yet copies of the relevant research comments on anomalies printed here are also welcome the address

optimal management with potential regime shifts we analyze how the threat of a potential future regime shift affects optimal management we use a simple general growth model to analyze four cases that involve combinations of stock collapse versus changes in system dynamics and exogenous versus endogenous probabilities of regime shift prior work in economics has focused on stock collapse with endogenous probabilities and reaches ambiguous conclusions on whether the potential for regime shift will increase or decrease intensity of resource use and level of resource stock we show that all other cases yield unambiguous results in particular with endogenous probability of regime shift that affects system dynamics the potential for regime shift causes optimal management to become precautionary in the sense of maintaining higher resource stock levels

optimal regulation of eutrophying lakes fjords and rivers in the presence of threshold effects eutrophication is a biological process that has an unfavorable economic impact on the economic value of the water basins it affects eutrophication depends on thresholds effects and optimal policies for the regulation of eutrophication must take this into account such optimal policies are derived in the present article by utilizing a novel technique in optimal control theory this technique facilitates a proper analysis of deterministic stock pollutants with thresholds effects a topic it is argued has been poorly understood in the literature copyright 2001 oxford university press

active learning a correction these changes stem from a bug which we discovered recently in the measurement error section of the passive learning part of our adaptive control code dual thus the results for the macrae model in section 2 of the paper are not affected because it does not include measurement error also the mean values in the first table above are not altered for the active learning and certainty equivalence solutions but rather only for the passive learning solution the modified results reported above show that the passive learning solutions to the single control variable abel model performed relatively worse than in our earlier report

the short run volatility of money stock targeting abstract the altered allocations of money market volatility obtained by alternative monetary policy procedures are illustrated by stochastic simulations of a staff monthly model the results indicate the nature of the tradeoff between short run volatility in the money stock and in the funds rate that is available to money stock targeting procedures

foreign exchange rate expectations micro survey data this paper analyzes the panel data of biweekly surveys on the yen dollar exchange rate expectations of forty four institutions for two years and contains four major findings first market participants are heterogeneous that is significant individual effects exist in their expectation formation second the individual effects have a characteristic of wishful expectations exporters expect yen depreciation and importers expect yen appreciation relative to others third many violate the rational expectations hypothesis fourth forecasts with long horizons show less yen appreciation than those with short horizons cross equation constraints implied by the consistency of the forecast term structure are strongly rejected in the data copyright 1990 by american economic association

is it risk explaining deviations from uncovered interest parity abstract this paper analyzes ex ante returns to forward speculation and asks if these returns can be explained by models of a foreign exchange risk premium after presenting evidence that both nominal and real expected speculative profits are nonzero the paper examines if real returns to forward speculation are consistent with consumption based models of risk premia estimates of the conditional covariance between real speculative returns and real consumption growth are presented and like ex ante returns to forward speculation they exhibit statistically significant fluctuations over time and often change sign

mitigation of the lucas critique with stochastic control methods abstract lucas in brunner k meltzer a h eds the phillips curve and the labor markets supplementary series to the journal of monetary economics 1976 pp 19 46 pointed out that when optimization is performed on a deterministic macro model the resulting policy may not reflect the true optimal solution private agents may react to announced policies and consequently model parameters will start to drift the aim of this paper is to develop a methodology for deriving an optimal policy in the presence of rational expectations and parameter drift this drift is captured by a stochastic optimization framework with time varying parameters the resulting optimal policy is capable of tracking changes in the parameters due to policy changes a numerical example illustrates how the methodology provides a way to mitigate the effects of the lucas critique

fixed versus flexible lessons from ems order flow abstract we extend the literature on regime dependent volatility in two ways first our microstructural model provides a qualitatively new explanation second we test implications of our model using europe s recent shift to rigidly fixed rates ems to emu in the model shocks to order flow induce more volatility under flexible rates because the elasticity of speculative demand is endogenously low leading to pronounced portfolio balance effects new data on ff dm transactions show that order flow had persistent effects on the exchange rate before emu parities were announced after announcement the ff dm rate was decoupled from order flow as the model predicts

adaptive control in the presence of time varying parameters in the previous chapters two strands of literature have been brought together the first strand is the research on time varying parameters following a return to normality model viz harvey and phillips 1982 and swamy and tinsley 1980 1 the second strand is the work on adaptive control in the tradition of tse and bar shalom 1973 and kendrick 1981 as indicated in chapter 2 given a time horizon of t periods the goal was to find the values of control variables for period 0 period 1 and so on until period t 1 which minimized the objective functional or cost to go in an adaptive control framework for each period in the time horizon say period t several trial or search values of the controls were tried 2 the optimal cost to go associated with each search control was then calculated following kendrick 1981 ch 10 the computations performed at time t were organized in three steps first the nominal value for the parameters for period t through t was computed using their estimates for time t 1 and their expected law of motion the first search control was also selected then the search for the optimal control was carried out this step included a use the search control and the nominal value for the parameters to get the projected states and covariances in period t 1 b get the nominal path for the states and controls for the period t 1 through t by solving the certainty equivalence ce problem with the projected states as the initial condition c compute the riccati matrices for periods t 1 t d update and project the covariances from period t 1 given t i e the covariance seen at point a above to t 1 e calculate the approximate cost to go for the period t through t f choose a new search control and repeat a f until all search points are evaluated g select the control which yields the minimum cost after the selected control was applied to the system and the process moved one step forward in time the estimates of the states and parameters were updated

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

learning by doing and the value of optimal experimentation abstract recent research on learning by doing has provided the limit properties of beliefs and actions for a class of learning problems in which experimentation is an important aspect of optimal decision making however under these conditions the optimal policy cannot be derived analytically because bayesian learning about unknown parameters introduces a nonlinearity in the dynamic optimization problem this paper utilizes numerical methods to characterize the optimal policy function for a learning by doing problem that is general enough for practical economic applications the optimal policy is found to incorporate a substantial degree of experimentation under a wide range of initial beliefs about the unknown parameters dynamic simulations indicate that optimal experimentation dramatically improves the speed of learning and the stream of future payoffs furthermore these simulations reveal that a policy which separates control and estimation and does not incorporate experimentation frequently induces a long lasting bias in the control and target variables while these sequences tend to converge steadily under the optimal policy they frequently exhibit non stationary behavior when estimation and control are treated separately

expectation errors in the foreign exchange market abstract a unified theoretical model is developed showing that forecasting errors can be explained by both informational rigidities and portfolio shifts this is applied to the brl usd exchange rate forecasting errors using a unique data set of daily consensus forecasts along with order flow derived from the fx futures market the results strongly support the theory

the returns to currency speculation in emerging markets the carry trade strategy involves selling forward currencies that are at a forward premium and buying forward currencies that are at a forward discount we compare the payoffs to the carry trade applied to two different portfolios the first portfolio consists exclusively of developed country currencies the second portfolio includes the currencies of both developed countries and emerging markets our main empirical findings are as follows first including emerging market currencies in our portfolio substantially increases the sharpe ratio associated with the carry trade second bid ask spreads are two to four times larger in emerging markets than in developed countries third and most dramatically the payoffs to the carry trade for both portfolios are uncorrelated with returns to the u s stock market this abstract was borrowed from another version of this item

active learning monte carlo results abstract the revival of interest in learning in stochastic control models invites the examination of some unanswered issues from earlier work following in the tradition of prescott and macrae we consider active learning to examine the question of when these methods are superior to passive learning in the earlier literature it was not possible to address this question because computer speeds were not great enough however modern supercomputers make it possible to reopen this issue in this paper we will examine two well known stochastic control models the macrae model and the abel model although no general conclusions can be drawn the results from the macrae model and the abel model indicate that in certain cases active learning may be superior to passive learning and certainty equivalence in the almost all cases we have analyzed so far active learning is superior to passive learning which in turn is superior to certainty equivalence