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

the dynamics of international capital flows results from a dynamic hierarchical factor model abstract the present paper examines the degree of comovement of gross capital inflows which is a highly sensitive issue for policy makers we estimate a dynamic hierarchical factor model that is able to decompose inflows in a sample of 47 economies into i a global factor common to all types of flows and all recipient countries ii a factor specific to a given type of capital inflows iii a regional factor and iv a country specific component we find that the latter explains by far the largest fraction of fluctuations in capital inflows followed by regional factors which are particularly important for emerging markets fdi and portfolio inflows as well as bank lending to emerging europe the global factor however explains only a small share of the overall variation we also employ dynamic panel and time series regressions to explain the determinants of the estimated components the global factor is shown to reflect u s financial conditions

the sullying effect of recessions previous work has established that recessions involve a cleansing effect so that in downturns only high productivity jobs remain but empirical evidence suggests job quality is procyclical jobs created in recessions are likely to be low paying and temporary this paper modifies previous models by adding on the job search which leads to an additional sullying effect calibration of the model suggests this offsetting sullying effect is likely to be much larger than the cleansing effect and can account for the procyclical match quality we observe in the data

wage rigidity and job creation recent research in macroeconomics emphasizes the role of wage rigidity in accounting for the volatility of unemployment fluctuations we use worker level data from the cps to measure the sensitivity of wages of newly hired workers to changes in aggregate labor market conditions the wage of new hires unlike the aggregate wage is volatile and responds almost one to one to changes in labor productivity we conclude that there is little evidence for wage rigidity in the data

sensitivity of job destruction to vintage and tenure effects matching models with endogenous job destruction typically deliver excessively volatile job destruction and moderate volatility of vacancies in our model vintage and tenure eects promote the creation of new matches that are temporarily more productive while reducing the survival of temporarily less productive matches this cleansing eect pro duces a counter cyclical in ow into unemployment removes the strong response of job destruction to productivity shocks and generates a downward sloping beveridge curve as in the data the model also generates more volatility in vacancies the job nding rate and labour market tightness

matching workers and jobs cyclical fluctuations in match quality using national longitudinal survey of youth data on tenure and wages this article analyzes the extent to which the level of job mismatching varies over the business cycle and how it is dealt with by the labor market i find significant cyclical variation in job match quality and an internalization of the variation by the labor market through wages mismatching occurs more during recessions but is primarily captured in starting wages the evidence suggests the cyclical phenomenon is one of general mismatching rather than an increased number of stopgap jobs during recessions

behavioral learning equilibria we propose behavioral learning equilibria where boundedly rational agents learn to use a simple univariate linear forecasting rule with correctly specified unconditional mean and first order autocorrelation in the long run agents learn the best univariate linear forecasting rule without fully recognizing the more complex structure of the economy an important feature of behavioral learning equilibria is simplicity and parsimony which makes coordination of individual expectations on such an aggregate outcome more likely in a first application an asset pricing model driven by ar 1 ar 1 dividends a unique behavioral learning equilibrium exists characterized by high persistence and excess volatility and it is stable under learning in a second application the new keynesian phillips curve multiple equilibria coexist learning exhibits path dependence and inflation may switch between low and high persistence regimes

technology policy interaction in frictional labour markets does capital embodied technological change play an important role in shaping labour market outcomes to address this question we develop a model with vintage capital and search matching frictions where irreversible investment in new vintages of capital creates heterogeneity in productivity among firms matched as well as vacant we demonstrate that capital embodied technological change reduces labour demand and raises equilibrium unemployment and unemployment durations in addition the presence of labour market regulations unemployment benefits payroll taxes and firing costs exacerbates these effects thus the model is qualitatively consistent with some key features of the european labour market experience relative to that of the u s it features a sharper rise in unemployment and a sharper fall in the vacancy rate and the labour share a calibrated version of our model suggests that this technology policy interaction could explain a sizeable fraction of the observed differences between the u s and europe copyright 2007 wiley blackwell

labor market volatility in the search and matching model the role of investment specific technology shocks abstract shocks to investment specific technology have been identified as a main source of u s aggregate output volatility in this paper we present a model with frictions in the labor market and explore the contribution of these shocks to the volatility of labor market variables namely unemployment vacancies tightness and the job finding rate thus our paper contributes to a recent body of literature assessing the ability of the search and matching model to account for the large volatility observed in labor market variables to this aim we solve a neoclassical economy with search and matching where neutral and investment specific technologies are subject to shocks the three key features of our model economy are i firms are large in the sense that they employ many workers ii adjusting capital and labor is costly iii wages are the outcome of an intra firm nash bargaining problem between the firm and its workers in our calibrated economy we find that shocks to investment specific technology explain 40 of the observed volatility in u s labor productivity moreover these shocks generate relative volatilities in vacancies and the workers job finding rate which match those observed in u s data relative volatilities in unemployment and labor market tightness are 55 and 75 of their empirical values respectively

ordinary least squares learning and nonlinearities in macroeconomics the paper reviews the literature on adaptive learning in macroeconomic settings where the formation of expectations is particularly relevant special attention will be given to simple two period overlapping generations models with a unique fixed point perfect foresight equilibrium in this kind of scenario eventual long term periodic and a periodic cycles are exclusively the result of the process of learning the outcome that high rates of money growth have a potentially destabilizing effect generating periodic fluctuations and chaos is emphasized the persistence of systematic forecast errors in a scenario where agents are supposed to act rationally is relevant in this context and it will be thoroughly discussed resorting to the notions of self fulfilling mistakes consistent expectations equilibria and beliefs equilibria

equity and bond flows to latin america and asia the role of global and country factors abstract this paper investigates the factors motivating the large capital flows to a number of developing countries in recent years we use monthly us capital flows to nine latin american and nine asian countries to analyze the behavior of bond and equity flows employing a panel data approach we find that although global factors the drop in us interest rates and the slowdown in us industrial production are important in explaining capital inflows country specific developments are at least as important especially for asia we also find that equity flows are more sensitive than bond flows to global factors but that bond flows are generally more sensitive to a country s credit rating and secondary market debt price

technological learning and labor market dynamics the search and matching model of the labor market fails to match two important business cycle facts i a high volatility of unemployment relative to that of labor productivity and ii a mild correlation between these two variables we address these shortcomings by focusing on the implementation process of technological innovation that is the empirical nding that new technologies are subject to a learning process we consider a novel source of business cycles namely uctuations in the ease or speed of technological learning and show that a search and matching model featuring such shocks can account for both facts moreover our model provides a new interpretation of news shocks discussed in the recent business cycle literature

the effect of implicit contracts on the movement of wages over the business cycle evidence from micro data in this paper we address the question of whether wages are affected by labor market conditions in a manner more consistent with a contract approach than with a standard spot market model from a simple implicit contract model we derive implications about the links between wages and past labor market conditions using individual data from the current population survey and the panel study of income dynamics we find that an implicit contract model with costless mobility describes these links better than either a simple spot market model or an implicit contract model with costly mobility

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

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

factor complementarity and labour market dynamics abstract we propose and estimate a dynamic stochastic general equilibrium model featuring search and matching frictions deep habits and a ces production function the model successfully replicates the cyclical properties of labour market variables in the us economy for three main reasons first two of the endogenous mechanisms of the model factor complementarity and unemployment benefits play a key role for explaining the amplification in unemployment and vacancies second deep habits have a smaller but significant role as an endogenous mechanism third capital augmenting productivity investment specific and matching efficiency innovations explain large part of the variation in labour market variables

embodied technical change and the fluctuations of unemployment and wages a matching model where technological change is partially embodied in the job match is shown to be successful in explaining the variability of unemployment and vacancies if we incorporate long term wage contracts into the model it also explains a number of stylized facts on the dynamics of real wages which have been found in the empirical labor literature

real wage cyclicality of job stayers within company job movers and between company job movers using the british new earnings survey panel data nespd for the period 1975 to 2001 we estimate the wage cyclicality of job stayers those remaining within single jobs in a given company within company job movers and between company job movers we also examine how the proportion of internal and external job moves varies over the business cycle we find that the wages of internal movers are slightly more procyclical and wages of external movers considerably more procyclical than those of stayers notwithstanding a decomposition shows that in britain wage cyclicality arises almost entirely from the procyclicality of wages for job stayers with across and within firm mobility playing a lesser role thus there is little evidence for rigid wage models that imply that employers use changes in job titles as a means of adjusting wages to the business cycle we also show that the distinctions between private and public sectors and between workers covered and uncovered by collective agreements have important impacts on the wage estimates of both stayers and movers

labor market dynamics under long term wage contracting abstract recent research seeking to explain the strong cyclicality of us unemployment emphasizes the role of wage rigidity this paper proposes a micro founded model of wage rigidity an equilibrium business cycle model of job search where risk neutral firms post optimal long term contracts to attract risk averse workers equilibrium contracts feature wage smoothing limited by the inability of parties to commit to contracts the model is consistent with aggregate wage data if neither worker nor firm can commit producing too rigid wages otherwise wage rigidity does not lead to a substantial increase in the cyclical volatility of unemployment

least squares learning and business cycles abstract this paper investigates whether the neoclassical growth framework augmented with least squares estimated heuristic rules may reproduce u s business cycles i consider various assumptions about the length of the information set the influence of contemporaneous data on current forecasts and the limit case in which learning is completed calibrated to the u s economy this model may generate endogenous business cycles that do not exist under perfect foresight if random productivity shocks are introduced then the model is more volatile than under rational expectations or constant gain learning and reproduces some key u s business cycles stylized facts

incentives in competitive search equilibrium this paper proposes a labor market model with job search frictions where workers have private information on match quality and eort firms use wage contracts to motivate workers in addition wages are also used to attract employees we de ne and characterize competitive search equilibrium in this context and show that it satis es a simple modi ed hosios rule the model is used to address the shimer puzzle related to the low volatility of the unemployment rate relative to the volatility of output observed in the data we nd that private information may increase the responsiveness of the unemployment rate to changes in productivity and in particular to changes in

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

excess worker reallocation workers face a trade off between macroeconomic and individual incentives to work in different occupations industries namely between search frictions and personal comparative advantages workers endowed with heterogeneous multi dimensional skills search for jobs that require different skill combinations in equilibrium specialized individuals contact few selected types of vacancies where they are likely to be hired those with weak comparative advantages are seldom chosen among competing applicants thus seek any job type in a tight labour market comparative advantages dominate waiting costs offsetting labour mobility across industries occupations excess worker reallocation is lower and matches are more successful consistently with direct and indirect evidence

portfolio capital flows hot or cold a distinction is often made between short term and long term capital flows the former are deemed unstable hot money and the latter are deemed stable cold money using time series analysis of balance of payments data for five industrial and five developing countries we find that in most cases the labels short term and long term do not provide any information about the time series properties of the flow in particular long term flows are often as volatile as short term flows and the time it takes for an unexpected shock to a flow to die out is similar across flows long term flows are also at least as unpredictable as short term flows and knowledge of the type of flow does not improve the ability to forecast the aggregate capital account copyright 1995 by oxford university press

the dynamic effects of neutral and investment specific technology shocks the neoclassical growth model is used to identify the short run effects of neutral technology shocks which affect the production of all goods homogeneously and investment specific shocks which affect only investment goods the real equipment price crucial for identifying the investment shocks experiences an abrupt increase in its average rate of decline in 1982 so the analysis is based on a split sample on the basis of the preferred specification the two technology shocks account for 73 percent of hours and 44 percent of output s business cycle variation before 1982 and 38 percent and 80 percent afterward the shocks also account for more than 40 percent of hours and 58 percent of output s forecast errors over a three to eight year horizon in both samples the majority of these effects are driven by the investment shocks

on the consistency of backward looking expectations the case of the cobweb in dynamic models of economic fluctuations backward looking expectations with systematic forecasting errors are inconsistent with rational behaviour in non linear dynamic models exhibiting seemingly unpredictable chaotic fluctuations however simple habitual rule of thumb backward looking expectation rules may yield non zero but nevertheless non systematic forecasting errors in a chaotic model expectational forecasting errors may have zero autocorrelations at all lags even for rational agents patterns in these forecasting errors may be very difficult to detect especially in the presence of small noise backward looking expectations are then not necessarily inconsistent with rational behaviour we investigate whether simple expectation schemes such as naive or adaptive expectations can be consistent with rational behaviour in the simplest of all non linear dynamic economic models the non linear cobweb model

specific capital and vintage effects on the dynamics of unemployment and vacancies in a reasonably calibrated mortensen and pissarides matching model shocks to average labor productivity can account for only a small portion of the uctuations in unemployment and vacancies shimer 2005a in this paper i argue that if vintage speci c shocks rather than aggregate productivity shocks are the driving force of uctuations the model does a better job of accounting for the data i add heterogeneity in jobs matches with respect to the time

the cost of business cycles and the stabilization value of unemployment insurance this paper o ers a new perspective on why labor market policies aimed at reducing the cost of business cycles may be warranted and how such policies can be designed in order to improve welfare to this end we develop a quantitative dynamic equilibrium model to illustrate how the contractual structure of the labor market may hide signi cant undiversi ed wage risk induced by aggregate uctuations the environment analyzed is such that the only imperfectly diversi ed risk workers bear is the risk of losing their job when the market for new contracts is depressed when we t the model to replicate the amount of wage variation estimated from micro data we obtain estimates of the potential value of stabilization policies that are substantially larger than those found in the literature we use this framework to examine several policy issues and in particular to show why state contingent unemployment insurance may dominate non contingent unemployment insurance schemes 2001 elsevier science b v all rights reserved jel classixcation e32 j41

chaotic learning equilibria chaotic temporary equilibrium trajectories under least squares learning are shown to exist in a standard version of the overlapping generations model theses trajectories show forecast errors that never vanish thus we do not find convergence to an equilibrium in which agents have perfect foresight complex trajectories can even be found in the case of savings functions which are monotonically decreasing in the expected gross rate of inflation in this case no cyclical or chaotic trajectories with perfect foresight exist thus learning alone is a source of chaotic dynamic journal of economic literature classification numbers d83 d84

technological learning and labor market dynamics learning and labor market dynamics the search and matching model of the labor market fails to match two important business cycle facts i a high volatility of unemployment relative to labor productivity and ii a mild correlation between these two variables we address these shortcomings by focusing on technological learning by doing the notion that it takes workers time using a technology before reaching their full productive potential with it we consider a novel source of business cycles namely fluctuations in the speed of technological learning and show that a search and matching model featuring such shocks can account for both facts moreover our model provides a new interpretation of recently discussed news shocks

matching models under scrutiny an appraisal of the shimer puzzle abstract two papers have recently questioned the quantitative consistency of the search and matching model shimer has argued that a textbook matching model is unable to explain the cyclical variation of unemployment and vacancies in the us economy costain and reiter have found the existence of a trade off in the model s performance any attempt to change the calibrated values to improve the model s ability to predict the business cycle jeopardizes its predictions of the impact of unemployment benefits on unemployment in surveying the literature originating in these findings i distinguish three different avenues that have been followed to correct the model change in wage formation change in the calibration and changes in the model specification the last approach seems to achieve the best results both from a business cycle and from a microeconomic viewpoint

self enforcing wage contracts we examine long term wage contracts between a risk neutral firm and a risk averse worker when both can costlessly renege and buy or sell labour at a random spot market wage a self enforcing contract is one in which neither party ever has an incentive to renege in the optimum self enforcing contract wages are sticky they are less variable than spot market wages and positively serially correlated they are updated by a simple rule around each spot wage is a time invariant interval and the contract wage changes each period by the smallest amount necessary to bring it into the current interval