learning to believe in sunspots a number of authors have shown that competitive economies may possess sunspot equilibria that is rational expectations equilibria in which purely extrinsic uncertainty affects equilibrium prices and allocations 2 such results demonstrate that it does not require a lack of faith in the rationality of market participants to believe that competitive markets may be subject to purely speculative fluctuations driven solely by expectations 3 the mere existence of sunspot equilibria as solutions to a system of marketclearing conditions however might not be judged sufficient to indicate that competitive markets with rational participants could ever be subject to speculative instability the sunspot equilibria represent states of affairs in which agents act differently in the case of different realizations of the sunspot variable and it is rational for each agent to do so but it might be thought unlikely that the beliefs of all the participants in the market could ever come to be coordinated so as to bring about an equilibrium of that kind it is rational to believe that sunspots convey information about future states of affairs once the economy is in a sunspot equilibrium but why would rational agents ever begin to believe in such a thing so as to create the conditions under which the belief is rational in order to address such a question one must go beyond the mere statement of the conditions for equilibrium and discussion of what states of affairs satisfy them one must specify an explicit dynamic process according to which the beliefs of agents adjust when out of equilibrium any exercise of this kind is necessarily unsatisfactory as there is no univocal meaning for the postulate of rational behavior outside of an equilibrium it may well be the case that

habit persistence money and overlapping generations abstract this paper provides a comprehensive characterization of the stationary and non stationary monetary equilibria in a two period pure exchange overlapping generations model with multiplicative habit persistence preferences somewhat surprisingly the upshot is that multiplicative habit persistence preferences do not affect the qualitative properties of the dynamical system in these models in addition the qualitative properties of models with subtractive and multiplicative habits are largely similar any possibility of cyclical fluctuations beyond periodicity two is also ruled out

stability of functional rational expectations equilibria abstract in this paper we examine a representative agent forecasting prices in a first order self referential overlapping generations model we first consider intermediate stage learning where agents update the forecasting rule every m periods we show that in theory and simulations the learning rule does not converge to the rational expectations equilibrium ree we next consider two stage learning where agents learn the functional mapping between the current forecast function and the previous forecast function we show that in theory and simulations the two stage learning rule converges to the ree journal of economic literature classifications numbers c62 c63 d83

a simple model of growth cycles with technology choice abstract in this study we develop a simple computable overlapping generations model that exhibits endogenous fluctuations the key assumption is that a firm can choose from multiple technologies of production since the model reduces to a piecewise linear map on the unit interval it allows us to conduct an in depth analysis of its dynamic properties particularly this piecewise linearization reveals the ability of the model to exhibit periodic attracting cycles of an arbitrarily large period as well as non periodic attractors furthermore it is demonstrated that the occurrence of periodic patterns is completely characterized by the rotation number or the devil s staircase

does working from home work evidence from a chinese experiment about 10 of us employees now regularly work from home wfh but there are concerns this can lead to shirking from home we report the results of a wfh experiment at ctrip a 16 000 employee nasdaq listed chinese travel agency call center employees who volunteered to wfh were randomly assigned to work from home or in the office for 9 months home working led to a 13 performance increase of which about 9 was from working more minutes per shift fewer breaks and sick days and 4 from more calls per minute attributed to a quieter working environment home workers also reported improved work satisfaction and experienced less turnover but their promotion rate conditional on performance fell due to the success of the experiment ctrip rolled out the option to wfh to the whole firm and allowed the experimental employees to re select between the home or office interestingly over half of them switched which led to the gains from wfh almost doubling to 22 this highlights the benefits of learning and selection effects when adopting modern management practices like wfh

public health spending old age productivity and economic growth chaotic cycles under perfect foresight abstract this paper analyses the dynamics of a double cobb douglas economy with overlapping generations and public health investments that affect the supply of efficient labour of the old aged it is shown that the positive steady state of the economy is unique moreover we provide necessary and sufficient conditions for the emergence of endogenous deterministic complex cycles when individuals are perfectly foresighted interestingly i the equilibrium dynamics shows rather complicated phenomena such as a multiplicity of bubblings depending on the size of the public health system and ii the higher the degree of thriftiness the likelier an economy is exposed to endogenous fluctuations because the need to save when young to support consumption when old is reduced

a characterization of erratic dynamics in the overlapping generations model abstract in this paper we characterize and give examples o wide classes of utility functions which generate erratic dynamics in the standard deterministic overlapping generations model erratic dynamics refers to feasible trajectories which are bounded but which do not converge to stationary points or periodic orbits we show that such trajectories are pareto efficient we introduce credit into the model and show how a constant credit expansion rate can result in erratic trajectories in prices and the real value of credit finally we briefly discuss certain technical aspects of the mathematics used and the statistical nature of the dynamics that can arise from deterministic dynamical systems

beliefs equilibria in an overlapping generations model we consider a standard two generations version of the overlapping generations model agents predict inflation rates on the basis of a perceived law of motion which is estimated by running a linear regression on past inflation rates we introduce the notion of beliefs equilibrium at such an equilibrium i the perceived law of motion is such that it fits the time series of inflation rates best and ii this time series of actual inflation rates is generated when agents use that perceived law of motion we show that beliefs might converge although inflation rates keep on fluctuating these fluctuations are consistent with the limit belief

inequality and the impact of growth on poverty comparative evidence for sub saharan africa abstract this study explores the extent to which inequality affects the impact of income growth on the rates of poverty changes in sub saharan africa ssa compared to non ssa based on an unbalanced panel of 86 countries over 1977 2004 for all three measures of poverty headcount gap and squared gap the impact of gdp growth on poverty reduction is a decreasing function of initial inequality the impacts are similar in direction for ssa and non ssa so that within both regions there are considerable disparities in the responsiveness of poverty to income growth depending on inequality nevertheless the income growth elasticity is substantially less for ssa implying relatively small poverty reduction response to growth

equivariant general equilibrium theory abstract the main purpose of this paper is to investigate the properties of a version of the general equilibrium model where symmetry considerations are explicitely taken into account this version called the equivariant model is shown to be a natural framework to study sunspot equilibria the problem of sunspot equilibria can then be viewed as one of symmetry breaking existence of asymmetric or sunspot equilibria is addressed through the dual approach of price income equilibrium analysis that splits the problem of breaking symmetries into two separate easier problems

asset price fluctuations without aggregate shocks we analyze the pricing of a productive asset in a class of dynamic exchange economies with heterogeneous infinitely lived agents and self enforcing intertemporal trades individual incomes fluctuate and are correlated preferences dividends and aggregate income are fixed almost all economies in this class have a unique stationary markovian equilibrium with fluctuations in asset prices as the set of unrationed households changes over time and states excess demand functions shift asset returns fluctuate and some households are shut out of asset markets examples suggest that the amplitude of these movements is negatively correlated with the productivity of the asset and with the penalty for default

endogenous vs exogenously driven fluctuations in vintage capital models in this paper we present a particular case of the creative destruction model of caballero and hammour quart j econ 111 1996 805 851 in which both exogenous and endogenous fluctuation sources are present we show that job creation follows a delayed differential equation with periodic coefficients the delay is equal to the optimal age of capital goods the period of the coefficients is equal to the period of an exogenous profitability cycle we mathematically show that job creation is asymptotically periodic with the same period as the profitability cycle furthermore using an explicit numerical method we find that replacement echoes generally dominate the short run dynamics finally we find that the combination of the two fluctuations sources favors the appearance of asymmetries in job creation and job destruction patterns

debt deleveraging and the liquidity trap a fisher minsky koo approach in this paper we present a simple new keynesian style model of debt driven slumps that is situations in which an overhang of debt on the part of some agents who are forced into rapid deleveraging is depressing aggregate demand making some agents debt constrained is a surprisingly powerful assumption fisherian debt deflation the possibility of a liquidity trap the paradox of thrift a keynesiantype multiplier and a rationale for expansionary fiscal policy all emerge naturally from the model we argue that this approach sheds considerable light both on current economic difficulties and on historical episodes including japan s lost decade now in its 18th year and the great depression itself

how important is precautionary saving we estimate how much of the wealth of a sample of psid respondents is held because some households face more income uncertainty than others we begin by solving a theoretical model of saving which we use to develop appropriate measures of uncertainty we then regress measures of wealth on our measures of uncertainty and find evidence that households engage in precautionary saving finally we simulate the wealth distribution that our empirical results imply would prevail if all households had the same uncertainty as the lowest uncertainty group we find that between 39 and 46 percent of wealth in our sample is attributable to the extra uncertainty that some consumers face compared to the lowest uncertainty group

can high inequality developing countries escape absolute poverty do the poor face the same prospects for escaping poverty in high inequality developing countries as in low inequality countries is it possible for inequality to be so great as to stifle prospects of reducing absolute poverty even when other initial conditions and policies are favorable to growth household survey data for developing countries suggest that initial distribution does affect how much the poor share in rising average incomes higher initial inequality tends to reduce growth s impact on absolute poverty by the same token higher inequality diminishes the adverse impact on the poor of general economic contraction combining this evidence with that from recent investigations of inequality s effect on growth the author finds that if inequality is high enough countries that would have very good growth prospects at low levels of inequality may see little or no overall growth and little progress in reducing poverty or even a worsening on both counts the data the author uses suggest that such cases do occur the precision with which key parameters have been estimated makes it difficult to say with confidence how common such cases are but they appear to be in the minority what appear to be the best available estimates suggest that about one fifth of the spells between surveys he analyzed were cases in which poverty was rising yet positive growth in the mean and hence falling poverty is predicted at zero inequality inequality can be high enough to result in rising poverty despite good underlying growth prospects

the role of real income level and income distribution in fulfillment of basic needs abstract using internationally comparable estimates of real gdp per capita along with world bank data on seven basic needs indicators and one income equality measure relative importance of real income level and income equality for improvement in the provision of basic needs is assessed on the basis of a multiple regression model income level seems important in almost all cases but the importance of income equality is observed only on a limited scale although income is probably more important in low income ldcs the relationships studied appear broadly similar in the low income and the middle income ldc contexts

international comovement of economic fluctuations a spatial analysis summary we consider the comovement of economic volatility across multiple countries using spatial models with data from 187 countries over the period of 1960 2007 we find a strong spatial comovement of economic volatility more interestingly the effect of geographical proximity on economic volatility comovement is strongest during the period of international shocks 1973 86 but almost disappears over the globalization era 1987 2007 by way of contrast the influence of trade relations in determining the comovement of economic volatility is significant over 1987 2007

reinventing foreign aid for inclusive and sustainable development kuznets piketty and the great policy reversal this survey essay reviews over 200 papers in arguing that in order to achieve sustainable and inclusive development foreign aid should not orient developing countries towards industrialisation in the perspective of kuznets but in the view of piketty abandoning the former s view that inequality will fall with progress in industrialisation and placing more emphasis on inequality in foreign aid policy will lead to more sustainable development outcomes inter alia mitigate short term poverty address concerns of burgeoning population growth train recipient governments on inclusive development fight corruption and mismanagement and avoid the shortfalls of celebrated kuznets conjectures we discuss how the essay addresses post 2015 development challenges and provide foreign aid policy instruments with which discussed objectives can be achieved in summary the essay provides useful policy measures to avoid past pitfalls output may be growing and yet the mass of the people may be becoming poorer lewis 1955 lewis led all developing countries to water proverbially speaking some african countries have so far chosen not to drink amavilah 2014 piketty 2014 has led all developing countries to the stream again and a challenging policy syndrome of our time is how foreign aid can help them to drink

political instability and economic growth in developing economies some specification empirics abstract the paper empirically explores the specification of the relationship between political instability pi and economic growth using data on different events of coups d etat in sub saharan africa it finds that when a principal component of the various pi events is employed in an augmented production function basic specification tests are met however specifying pi using the separate events such as successful coups results in a potentially misspecified relationship reduced model fit and underestimation of the adverse pi effect

exponentially fading memory learning in forward looking economic models abstract in this paper we analyze forward looking economic models under bounded rationality we consider a learning mechanism characterized by exponentially fading memory with a learning step not vanishing in the limit the dynamics of the model under bounded rationality can be parametrized with respect to the memory of the learning mechanism we show that memory plays a stabilizing role in a local sense it induces local convergence towards a stationary rational expectations equilibrium and in some cases it does not allow for nonperfect foresight attractors obtained through local bifurcations we discuss this learning mechanism in pure exchange overlapping generations models we also analyze models with predetermined state variables in this setting the effect of memory on the learning dynamics is controversial

optimal policy in og models in the present paper general stationary overlapping generations economies with many commodities in every period and many different consumers in every generation are considered a government maximizes an utilitarian social welfare function that is the sum of weighted averages of utilities for generations through fiscal policy i e monetary transfers and taxes both situations with and without time discounting are considered it is shown that if the discount factor is sufficiently close to one then the optimal policy stabilizes the economy i e the equilibrium path has the turnpike property moreover the fiscal policy is shown to be time consistent

the household fallacy we refer to the idea that government must tighten its belt as a necessary policy response to higher indebtedness as the household fallacy we provide a reason to be skeptical of this claim that holds even if the economy always operates at full employment and all markets clear our argument rests on the fact that in an overlapping generations olg model changes in government debt cause changes in the real interest rate that redistribute the burden of repayment across generations we do not rely on the assumption that the equilibrium is dynamically inefficient and our argument holds in a version of the olg model where the real interest rate is always positive

happiness and productivity some firms say they care about the well being and happiness of their employees but are such claims hype or scientific good sense we provide evidence for a classic piece rate setting that happ

economic growth inequality and poverty estimating the growth elasticity of poverty summary this paper uses a new data set of 126 intervals from 60 developing countries to analyze the growth elasticity of poverty that is how much does poverty decline in percentage terms with a given percentage rise in economic growth the data set is both broader in coverage and more selective in terms of quality controls than those used in the past the study finds that while economic growth does reduce poverty in developing countries the rate of poverty reduction depends very much on how economic growth is defined controlling for changes in income inequality when economic growth is measured by changes in survey mean income consumption the growth elasticity of poverty excluding eastern europe and central asia is 2 79 that is a 10 increase in the survey mean will reduce poverty 1 00 person day by 27 9 but when growth is measured by changes in gdp per capita the growth elasticity of poverty is a statistically insignificant 2 27 which is lower than has previously been estimated

retrospectives edgeworth s hedonimeter and the quest to measure utility in this article i discuss some earlier debates about the foundations of utility and its measurement focusing on the contributions of francis y edgeworth 1845 1926 a famous british economist who was a leader in the development of a more mathematically structured economics in the late 1800s and irving fisher 1867 1947 one of the first quantitative u s economists best known today for his work on the quantity theory and interest rate theory edgeworth argued that utility was directly measurable and that new developments in physio psychology would make it possible to develop a hedonimeter that would allow economists to develop a firm physiological underpinning of utility fisher while agreeing with edgeworth that it was important to have a workable measure of utility disagreed with edgeworth about the possibility of doing so with a hedonimeter and hence of having any physiological underpinnings of utility he argued that instead of searching for physiological underpinnings of utility economists should instead rely upon backward induction from observed behavior to measured utility neither of these views about the possibility of utility measurement carried through and attempts to measure utility were abandoned in the 1930s when utility measurement and happiness considerations were determined to be outside the purview of economics both edgeworth and fisher knew that their approaches to utility measurement opened up a pandora s box of problems they opened that box nonetheless because they felt that theoretical economics had to be relevant to policy and to be relevant it had to face the problems

equilibrium models displaying endogenous fluctuations and chaos abstract this paper surveys current developments in dynamic general equilibrium theory concerned with conditions under which endogenous fluctuations are possible existing contributions are divided into two classes the larger one consists of models with a unique perfect foresight equilibrium while the second includes models where equilibrium is indeterminate and the set of equilibria involving endogenous fluctuations includes sunspots equilibria while the two classes of models involve oscillations of different natures and with different policy implications we show that both are consistent with optimizing behavior and competitive equilibrium

the emergence of chaos from classical economic growth this paper shows how fluctuations of an erratic and unstable nature can emerge from the classical deterministic economic growth process implications of the analysis would appear to be at least two first pronounced changes in the way an economy behaves need not cause us to reject our understanding of how it works second we need not seek in exogenous forces an explanation as to why behavioral patterns change and why it may be so difficult to anticipate future events from the profile of past experience

irregular growth cycles this paper uses the familiar neoclassical theory of capital accumulation to show how complex behavior can emerge from quite simple economic structures indeed when sufficient nonlinearities and a production lag are present the interaction alone of the propensity to save and the productivity of capital can lead to growth cycles that exhibit a wandering sawtooth pattern not unlike those observed in reality these fluctuations need not converge to a cycle of any regular periodicity so they are not quasi periodic because such chaotic trajectories are unstable errors of estimation in parameters or initial conditions however tiny will accumulate rapidly into substantial errors of forecast moreover periods of erratic cycling can be interspersed with periods of more or less stable growth evidently the future behavior of a model solution cannot be anticipated from its patterns in the past a situation that seems to mimic experience apparent structural change and unpredictability is explained in the present theory by a deterministic single equation model random shocks play no role so the reader can visualize just what it is we are are talking about a noteworthy simulation is presented in figure 1 for gnp in a growth model that is described below in section iii a period of relatively rapid growth is followed by a period of cycles then remarkably for a considerable time about twenty periods apparently steady state growth occurs wandering cycles however emerge another brief period close to the steady state appears again toward the end of the series i establish conditions of savings and productivity that lead to results of this kind this analysis makes use of the mathematical theory of chaos which in the form exploited here originated in the work of edward lorenz a formal definition of chaos and sufficient conditions for chaotic trajectories were provided in a seminal paper by t y li and james yorke a survey of these related contributions is found in yorke and evelyn yorke this theory was introduced into economics by jess benhabib and myself 1981 where we showed that sequences of rational choices can be erratic when preferences depend on experience in a certain way by michael stutzer who provides a detailed analysis of trygve haavelmo s growth model by benhabib and myself 1980 in an application of the overlapping generations model and in my forthcoming study of the classical growth model

liquidity profit rate cycles in a capitalist economy abstract a monetary economy consisting of independent capitalist firms in which workers spend wages instantly and labor is not scarce is studied the firms create demand for each other s output through their capital outlays and create the backing for money through borrowing when all firms are identical in behavior and initial conditions and the rate of growth of money is constant the economy may be unstable around the equilibrium steady state growth path due to strong accelerator effects and follow a limit cycle trajectory

viewpoint a microfoundation of monetary economics in this lecture i explain what the microfoundations of money are about and why they are necessary for monetary economics then i review recent developments of a particular microfoundation of money commonly known as the search theory of money finally i outline some unresolved issues dans cette presentation l auteur explique ce que sont les microfondations de la monnaie et pourquoi elles sont necessaires a l economie monetaire ensuite il passe en revue certains developpements recents d une microfondation particuliere de la monnaie connue sous le nom de theorie de la recherche de la monnaie enfin l auteur fait le tour d un ensemble de problemes qui restent sans solution pour le moment

endowments stability and fluctuations in og models abstract in the present paper we consider a stationary overlapping generations model with many commodities and many different consumers and investigate how the distribution of endowments influences the dynamical properties of the model such as stability of steady states and existence of cycles our main results are 1 1 preferences place no restrictions on stability properties of steady states 2 2 cycles exist for all aggregate savings real or nominal and 3 3 equilibria of economies with equilibria close to a no trade equilibrium with constant prices are either steady states or equilibria which converge to a steady state in backward time and another steady state in forward time these results are obtained generically in utility functions and do not depend on whether the utility functions are of the discounted form or not

recessions and the vulnerable abstract this study evaluates the impact of recessions on households vulnerable to poverty the results indicate that recessions impact vulnerable households asymmetrically in comparison to the impact of growth on poor households we also demonstrate that this outcome is significantly influenced by a country s extent of development we argue that a direct consequence of the foregoing is that the efficacy of growth in poverty reduction tends to be under stated by conventional measures of poor households responses to economic growth and that safety nets need to be constructed to incorporate vulnerability to recessions

observational equivalence of the overlapping generations and the cash in advance economies abstract this paper demonstrates that any equilibrium in an overlapping generations economy a la grandmont 1985 can be supported as an equilibrium in a cash in advance economy a la lucas and stokey 1987 and vice versa thus business cycles could occur at real life frequencies

does child undernutrition persist despite poverty reduction in developing countries quantile regression results abstract the eradication of child undernutrition and extreme poverty are important objectives for most societies countries with higher national incomes usually improve in both dimensions but not always at the same rate using quantile regression we show that poverty rates tend to decline with increased income at a roughly constant elasticity in contrast while the prevalence of child wasting declines at that same elasticity where it is most widespread the elasticity becomes smaller as wasting becomes less prevalent this finding suggests a greater need for increasingly targeted interventions to achieve a given reduction in undernutrition as its prevalence declines

living in an imaginary world that looks real abstract in the paper we show using standard approaches general equilibrium modeling and the assumption of complete rationality that the macroeconomic environment is endogenous and is indeterminate specifically it is argued without resorting to sunspot type arguments that microeconomic fundamentals do not suffice to characterize the economy at the macro level in particular we show how perceptions of rational agents of the workings of the economy a shape the environment b affect the environment sufficiently to ensure that rational economic agents find the observed environment consistent with their beliefs even though it is not as a by product we illustrate that endogenous macro uncertainty can arise as an outcome if rational economic agents whose expectations are anchored on endogenous variables expect them to arise finally we show that systematic errors can persist indefinitely under rationality

on rational dynamic strategies in infinite horizon models where agents discount the future abstract in this paper we show that the equilibrium dynamics arising in three models of rational choice over an infinite horizon are described by choice functions belonging to huge classes of maps including chaotic ones the results are obtained by studying the relationship between the primal functions of the models and the corresponding choice functions the three models are the economic growth model with discounting a duopoly game with alternate moves a duopoly with simultaneous moves

on endogenous competitive business cycles the belief that the long run equilibrium of a competitive monetary economy that does not experience any exogeneous shocks whether originating from the external environment or from policy should be modelled as a state that is stationary or perhaps growing at a constant rate seems to be deeply rooted in the mind of some economists

rational choice and erratic behaviour in this paper we show that rational choice in a stationary environment can lead to erratic behaviour when preferences depend on experience we mean by erratic behaviour choice sequences that do not converge to a long run stationary value or to any periodic pattern early investigations of the effects of experience on choice goes back to pareto see also benhabib 1979 some keynesian theories of the consumption function incorporate the effects of experience and habit formation on current levels of consumption duesenberry 1949 modigliani 1949 and brown 1952 a general model of experience dependent choice was described in day 1970 and investigated in day and kennedy 1971 while the specific issue of the existence of stable representable long run consumer demand when tastes vary endogenously has been treated by gorman 1967 pollak 1970 1976 weizsaicker 1971 mccarthy 1974 and hammond 1976 pollak gave conditions for the representability of long run choice when the equations of preference dependence are linear and utility additive hammond in a generalization of these findings provides conditions for stable representable long run choice when preferences are acyclic a condition which in essence assures convergence to a long run choice

equilibrium and optimality some imprints of david gale abstract the paper is a review of some of the themes to which david gale made lasting contributions it touches upon a number of the fundamental issues in the walrasian equilibrium theory existence uniqueness and stability the overlapping generations model non optimality and indeterminacy of competitive equilibria the von neumann equilibrium as a turnpike and in the theory of decentralized intertemporal allocation through competitive prices efficiency and golden rules duality and existence of optimal programs

unemployment migration and growth economic development is typically accompanied by migration from rural to urban employment this migration is often associated with significant urban underemployment both factors are important in the development process we consider a neoclassical growth model with rural urban migration and urban underemployment which arises from an adverse selection problem in labor markets we demonstrate that rural urban migration and underemployment can be a source of development traps and can give rise to a large set of periodic equilibria display long periods of uninterrupted growth punctuated by brief but severe recessions

the emergence of equilibrium cycles in a monetary economy with a separable utility function abstract this paper analyzes the dynamic properties of the monetary economy when money held during the period induces some utility it is shown that the price level and real money balances may have chaotic dynamic paths even if the utility function is separable in real money balances and consumption a crucial point is that a constraint on the utility of money yields the wealth effect that inflation will reduce the real value of assets hence as in the overlapping generations model the conflict between substitution and wealth effects may cause globally stable periodic orbits as well as the complicated dynamics

a family production overlapping generations economy abstract this paper provides a theoretical analysis of an overlapping generations economy in which production decisions and input output allocations are all carried out at the family level i consider a single class of output allocation schemes and various degrees of knowledge about the production technology under complete knowledge i show that a family organizational structure in which everyone receives his marginal contribution to output invests less in physical capital than under a perfectly competitive equilibrium environment under incomplete knowledge i analyze and compare how beliefs about the input output relationship affect the physical capital accumulation dynamics and the long run standards of living

externalities internalization and fluctuations in this paper the authors introduce consumption externalities as developed by k arrow in overlapping generations economies they show how the internalization of externalities through exchanges at markets for externalities may give rise to new phenomena such as altered stability properties and fluctuations even though it restores optimality copyright 1997 by economics department of the university of pennsylvania and the osaka university institute of social and economic research association

two period cycles in a three period overlapping generations model abstract we study the properties of two period monetary cycles in simple pure exchange overlapping generations economies in which the households live for three periods we demonstrate that these economies can support cycles under a much broader and arguably more plausible range of assumptions than the analogous two period economies we show that economies that fail the well known grandmont econometrica 53 1985 995 condition can have cycles and that economies that satisfy the condition can fail to have cycles in addition we show that economies can have monetary cycles when they do not have conventional monetary steady states and when aggregate demand for assets is not decreasing in the real return rate at a gross real rate of unity

correlated equilibria and sunspots we examine when sunspots uncertainty that has no influence on endowments preferences or technology can affect equilibrium in a simple two period two commodity two class economy we find that such an effect is possibly only if the signals random variables that different agents observe are imperfectly correlated neither perfectly correlated nor independent and at least one commodity is a giffen good for two special cases we characterize the set of equilibria due to sunspots we conclude by showing the intimate connection between the sunspot equilibria of our finite horizon model and those of the overlapping generations literature

expectational diversity in monetary economies abstract we investigate an overlapping generations monetary economy in which expectations depend upon backward looking predictors of the future price level we use discrete choice theory to model how agents select a predictor based on its past forecast error letting the number of available predictors tend to infinity we obtain the large type limit of the system taking the large type limit dramatically reduces the number of free parameters while maintaining the expectational diversity which we argue is necessary for constructing plausible learning based models the model s dynamics are strongly influenced by the intensity of choice which measures how sensitive an agent s predictor choice is to differences in forecast errors across predictors when the intensity of choice is low the monetary steady state is stable as the intensity of choice increases and if certain parametric restrictions are met the system undergoes a hopf bifurcation in which case we document the existence of highly irregular equilibrium price paths

confidence crashes and animal spirits this article is an attempt to reformulate what i take to be two key insights from keyness general theory keynes 1936 the first is that there is something profoundly different about the labour market from most other markets in the economy the second is that the beliefs of participants in the asset markets have an independent influence on economic activity in the language of modern dynamic general equilibrium theory we would say that there is a continuum of labour market equilibria and that beliefs about the value of the stock market select an equilibrium the general theory contains many ideas some of which are internally inconsistent and keynes did not try to reconcile his theory with walrasian economics that task was carried out by a group of interpreters including hansen 1936 and hicks 1937 the current dominant paradigm new keynesian economics originated with the third edition of samuelson s 1955 undergraduate textbook in which he introduced the idea of the neoclassical synthesis according to this doctrine the economy is keynesian in the short run but classical in the long run the short run is defined as the period over which not all prices have had time to adjust to their walrasian levels this article introduces a different interpretation of the key ideas from the general theory 1 although my work is inspired by keynesian economics this article is not about the history of thought i offer a way of formulating the idea that market economies are not inherently self stabilising without assuming that prices or wages are prevented from adjusting to their equilibrium levels by some kind of friction instead i claim that high persistent unemployment is a potentially permanent feature of a market economy in a steady state equilibrium

carl s nonlinear cobweb abstract this essay surveys some of my work on expectations learning and bounded rationality within the classical cobweb model following early inspiring ideas from carl chiarella in particular i focus on the role of nonlinear dynamics learning and heterogeneity within the cobweb framework and how price fluctuations in the cobweb theory fit with observations of individual and aggregate behaviour from laboratory experiments with human subjects

population and the environment a parable of firewood and other tales the author analyzes the relationship between population and the environment with a focus on the role which environmental degradation and natural resources depletion may play in producing the population pressure which lies behind such degradation and depletion especially in developing countries the principal conclusion of this analysis is that the possibilities for a stable equilibrium between human population and its environment are quite limited i show that parental altruism toward their children can only make matters worse if socially unchecked by leading to an increase of the birthrate in every environmental state in comparison with that which would occur in its absence excerpt

what can new survey data tell us about recent changes in distribution and poverty it has been claimed that in recent times the poor have lost ground both relatively and absolutely even when average levels of living have risen this article tests that claim using household surveys for 67 developing and transitional economies over 1981 94 it finds that changes in inequality and polarization were uncorrelated with changes in average living standards distribution improved as often as it worsened in growing economies and negative growth was often more detrimental to distribution than positive growth overall there was a small decrease in absolute poverty although with diverse experiences across regions and countries almost always poverty fell with growth in average living standards and rose with contraction

basic human needs the plateau curve abstract the satisfaction of basic human needs in developing countries follows a nonlinear curve relative to per capita income asymptotically approaching a limiting level within this general relationship some countries are more efficient than others in improving basic needs at lower per capita income levels infant mortality rates in 116 countries from 1950 to 1980 are analyzed to identify factors affecting a country s efficiency in reaching infant mortality targets relative to its gross domestic product per capita the determinants of efficiency include export structure internal distribution late development and access to education implications for development policy are discussed

expectations in stability and in viability in realistic overlapping cohorts models abstract in this paper we shall consider the multi cohort generalization of overlapping generations models namely overlapping cohorts olc models each time period consumers of different ages form expectations on future interest rates and conditionally maximize utility arising from their remaining consumption paths under the condition of zero bequest for every time period a coordinator determines the new interest rate to ensure that the total consumption is equal to the total endowment of the society the message of the paper is the following 1 in olc the dynamics generated by rational expectations is frequently not only unstable but unviable 2 in olc the dynamics generated by naive expectations is practically asymptotically stable and viable around the lower steady state

revisiting cross country poverty convergence in the developing world with a special focus on sub saharan africa abstract the literature on poverty convergence is sparse and much of the empirical evidence relies on ravallion 2012 who found a lack of poverty convergence across some ninety less developed countries ldcs during 1980 2007 this paper revisits cross country poverty convergence using data from the same sources but an extended period of 1980 2014 we find that while poverty convergence remains absent across ldcs it is present in sub saharan africa ssa during the extended period initial poverty canceling the effectiveness of growth in reducing poverty explains the lack of poverty convergence across ldcs while a strong growth effect dominating the adverse effect of initial poverty on growth effectiveness explains the strong poverty convergence found in ssa a direct adverse link between initial poverty and subsequent growth which ravallion 2012 recognized as the main impediment to poverty convergence during 1980 2007 is not found in this study

habit persistence in overlapping generations economies under pure exchange abstract this paper analyzes the implications of habit persistence preferences for savings and equilibrium dynamics in the context of an overlapping generations model under pure exchange we show that habit persistence can convert an economy which otherwise has no role for government currency into an economy where there does exist a role for such currency further the increased saving induced by habit persistence implies that governments are able to float higher levels of deficits in such economies relative to economies without habit persistence the paper also shows that relative to standard preferences habit persistence preferences cause the savings function to become decreasing in the rate of interest at lower values for relative risk aversion this is of particular interest since the paper demonstrates that this result is closely related to the relative success of models with habit persistence in explaining the equity premium puzzle journal of economic literatureclassification numbers e21 e32

the evolving role of agriculture in poverty reduction an empirical perspective abstract the role of agriculture in development remains much debated this paper takes an empirical perspective and focuses on poverty as opposed to growth alone the contribution of a sector to poverty reduction is shown to depend on its own growth performance its indirect impact on growth in other sectors the extent to which poor people participate in the sector and the size of the sector in the overall economy bringing together these different effects using cross country econometric evidence indicates that agriculture is significantly more effective in reducing poverty among the poorest of the poor as reflected in the 1 day squared poverty gap it is also up to 3 2 times better at reducing 1 day headcount poverty in low income and resource rich countries including those in sub saharan africa at least when societies are not fundamentally unequal however when it comes to the better off poor reflected in the 2 day measure non agriculture has the edge these results are driven by the much larger participation of poorer households in growth from agriculture and the lower poverty reducing effect of non agriculture in the presence of extractive industries

ergodic fluctuations in deterministic economic models abstract nonperiodic business fluctuations are shown to exist with positive measure generically and to behave like stationary stochastic processes in the standard dynamic macro model the implication is that so called chaotic fluctuations are probable for random initial conditions in a large class of recursive economies

contracting with private rewards i extend the canonical moral hazard model to allow the agent to face endogenous and non contractible uncertainty the agent works for the principal and simultaneously pursues private rewards i establish conditions under which the first order approach remains valid the model adds to the literature on intrinsic versus extrinsic motivation specifically to induce higher effort at work the contract may offer higher rewards but flatter incentives the contract change makes the agent reevaluate his work life balance larger employment rewards lessens the incentive to pursue private rewards the greater reliance on labor income then necessitates weaker explicit incentives to induce high effort

not by growth alone the role of the distribution of income in regional diversity in poverty reduction this study examines the role of the distribution of income in determining the responsiveness of poverty to income growth and changes in income inequality using panel data of 58 developing countries for the period 1980 1998 we show that the large cross regional variation in the capacity of income growth to reduce poverty i e the income elasticity is largely explained by differences in the initial distribution of income and present region and time specific estimates of the income and gini elasticities of poverty we find that the income elasticity of poverty in the mid 1990s equals 1 31 on average and ranges from 0 71 for sub saharan africa to 2 27 for the middle east and north africa and that the gini elasticity of poverty equals 0 80 on average and ranges from 0 01 in south asia to 1 73 in latin america furthermore we show that while differing income growth rates account for most of the regional diversity in poverty trends the additional impact of differences across regions in rates of inequality change and income and inequality elasticities of poverty is almost always significant and far too large to be ignored most notably so in eastern europe and central asia

are you happy while you work using a new data source permitting individuals to record their well being via a smartphone we explore within person variance in individuals well being measured momentarily at random points in time we find paid work is ranked lower than any of the other 39 activities individuals can report engaging in with the exception of being sick in bed precisely how unhappy one is while working varies significantly with where you work whether you are combining work with other activities whether you are alone or with others and the time of day or night you are working

institutions and short run macroeconomic performance abstract this paper reviews the growing interest in institutions it argues that the explanation for this interest is a fresh awareness of how institutions affect economic performance this connection arises because many economic interaction take the form of one or other of three classic games prisoners dilemma coordination and chicken and the outcome in these games and hence performance of the economy is influenced by the institutional context of these interactions the paper provides a detailed illustration of this argument with a survey of the literature which relates unemployment performances to the institutions of wage setting in oecd countries