optimal partnership in a repeated prisoner s dilemma this paper studies informational partnerships in a repeated prisoner s dilemma with random matching assuming that players observe the play within but not across partnerships we find the surprising result that the relation between the observability of actions and the sustainability of cooperation is non monotonic increasing partnerships beyond a certain optimal size hardens cooperation although it improves observability d 2005 elsevier b v all rights reserved

communication in repeated games with private monitoring abstract the paper considers repeated games where each player can be observed by only a subset of the other players and where players can make public announcements about the behavior of the players they observed we address the following question what is the minimal level of observability that is required to obtain efficient outcomes the main result is that the limit set of sequential equilibrium payoffs when the discount factor tends to one contains the set of individual rational payoffs whenever each player is observed by at leasttwoother players journal of economic literatureclassification number c73

competition between private and public schools vouchers and peer group effects a theoretical and computational model with tax financed tuition free public schools and competitive tuition financed private schools is developed students differ by ability and income achievement depends on own ability and on peers abilities equilibrium has a strict hierarchy of school qualities and two dimensional student sorting with stratification by ability and income in private schools high ability low income students receive tuition discounts while low ability high income students pay tuition premia tuition vouchers increase the relative size of the private sector and the extent of student sorting and benefit high ability students relative to low ability students

consumption smoothing and the current account evidence for france 1970 1996 abstract this paper estimates a simple consumption smoothing model of the french current account and examines its capacity to predict recent developments in france s external performance the model views the current account as a buffer through which private agents can smooth consumption over time in response to temporary disturbances to output investment and government expenditure the empirical results indicate that the model performs well overall and predicts correctly the sharp turnaround in france s external accounts observed in the past 3 years a feature of the data that conventional models of trade flows based on income and relative price variables appear unable to explain

changes in the u s wage structure 1963 1987 application of quantile regression the 1980 s witnessed rapid changes in the structure of wages in the united states in this study recently developed techniques for quantile regression are applied to every march current population survey since 1964 and changes in the return to schooling and experience at different points of the wage distribution are examined the quantile regression technique parsimoniously describes the entire conditional wage distribution this conditional distribution is used to examine changes in within group wage inequality as measured by the difference between conditional quantiles two linear models are considered a simple one group model and a 16 group model the results suggest that the returns to schooling and experience differ across quantiles of the wage distribution but their patterns of change are similar significant differences in wage inequality are also found across the various skill groups the paper also presents a new imputation method for cps data

permanent and transitory movements in labor income an explanation for excess smoothness in consumption many have argued that if labor income is difference stationary the permanent income hypothesis predicts that consumption should be relatively volatile in u s aggregate data labor income is well characterized as having a unit root however consumption turns out to be relatively smooth this anomaly is known as deaton s paradox i resolve deaton s paradox by providing decompositions of labor income into permanent and transitory components these preserve the univariate dynamic properties of labor income however when agents distinguish permanent and transitory movements in their labor income as the rational expectations hypothesis asserts they should the permanent income hypothesis correctly predicts the observed smoothness in consumption

efficiency results in n player games with imperfect private monitoring abstract we demonstrate that efficiency is achievable in a certain class of n player repeated games with private almost perfect monitoring our equilibrium requires only one period memory and can be implemented by two state automata furthermore we show that this efficiency result holds with any degree of accuracy of monitoring if private signals are hemiindependent whereas most existing research focuses on two player cases or only a special example of n player games our results are applicable to a wide range of n player games of economic relevance such as trading goods games and price setting oligopolies

existence of nontrivial equilibria in repeated games with imperfect private monitoring abstract we consider finitely repeated games with imperfect private monitoring and provide several sufficient conditions for such a game to have an equilibrium whose outcome is different from repetition of nash equilibria of the stage game surprisingly the conditions are consistent with uniqueness of the stage game equilibrium a class of repeated chicken is shown to satisfy the condition

the political economy of urban transport system choice this paper analyzes the political economy of transport system choice with the goal of gaining an understanding of the forces involved in this important urban public policy decision transport systems pose a continuous trade off between time and money cost so that a city can choose a fast system with a high money cost per mile or a slower cheaper system the paper compares the socially optimal transport system to the one chosen under the voting process focusing on both homogeneous and heterogeneous cities while considering different landownership arrangements the analysis identifies a bias toward underinvestment in transport quality in heterogeneous cities

a new approach to decomposition of economic time series into permanent and transitory components with particular attention to measurement of the business cycle abstract this paper introduces a general procedure for decomposition of non stationary time series into a permanent and transitory component allowing both components to be stochastic the permanent component is shown to be a random walk with drift and the transitory or cyclical component is a stationary process with mean zero the decomposition methodology which depends only on past data and therefore is computable in real time is applied to the problem of measuring and dating business cycles in the portwar u s economy we find that measured expansions and contractions are of roughly equivalent duration and that our dating of cyclical episodes tends to lead the traditional nber dating and to a lesser extent the growth cycle chronology of zarnowitz and boschan 1977

human capital inequality and growth a local perspective abstract a recent body of work has demonstrated the crucial role played by local human capital externalities and local school funding in generating socio economic segregation persistent poverty and low aggregate income or productivity growth we present a simple model which captures the main insights from this literature and prove three general propositions first minor differences in education technologies preferences wealth or minor imperfections in capital markets can lead to a high degree of stratification second stratification makes inequality in education and income more persistent across generations the same is true for total wealth provided the rich succeed in capturing the rents created by their secession finally this polarization or urban areas can be very inefficient especially in the long run

collusion with almost no information we analyze noncooperative collusion in an infinitely repeated bertrand game where each of the n firms receives a privately observed i i d cost shock in each period and firms only and privately observe whether they have won the unit mass of consumers no other information is available and no communication is allowed we prove that there exist equilibria in private strategies approximating first best profits when firms are sufficiently patient in particular productive efficiency obtains in the limit

beliefs and private monitoring this paper develops new recursive set based methods for studying repeated games with private monitoring for any nite state strategy prole we nd necessary and sucient conditions for whether there exists a distribution over initial states such that the strategy together with this distribution form a correlated sequential equilibrium also for any given correlation device for determining initial states including degenerate cases where players initial states are common knowledge we provide necessary and sucient conditions for the correlation device and strategy to be a correlated sequential equilibrium or in the case of a degenerate correlation device for the strategy to be a sequential equilibrium we also consider several applications in these we show that the methods are computationally feasible show how to construct and verify equilibria in a secret price setting game

temporary and permanent government spending in an open economy some evidence for the united kingdom abstract this paper investigates the effects of government spending changes on a small open economy in an intertemporal substitution framework if agents internalize the government s budget constraint temporary and permanent spending have different implications for wealth and consequently different effects on output and the balance of trade estimation of these effects isolates the different channels through which government spending can influence economic activity main findings for the united kingdom are that government spending i crowds out private spending ii is directly productive and iii when rising permanently leads to a negative wealth effect which induces a large rise in work effort

international capital mobility amongst the major industrialised countries too little or too much this paper examines capital flows among the major industrialized countries with a view to assessing m feldstein and c horioka s 1980 claim that international capital mobility is limited it argues that saving investment correlation tests are inherently flawed and proposes an alternative methodology for testing the degree of international capital mobility it finds that capital flows have been excessive in the sense that they are driven by speculative forces rather than by economic fundamentals copyright 1995 by royal economic society

asymmetry of customer loss and recovery under endogenous partnerships theory and evidence this article is inspired by real world phenomena that firms lose customers based on imprecise information and take a long time to recover if consumers are playing an ordinary repeated game with fixed partners there is no clear reason why recovery happens slowly however if consumers are playing an endogenously repeated game a class of simple efficient equilibria exhibits the asymmetry of fast loss and slow recovery of customers after a bad signal exit is systematic but formation of a new partnership is random we also give empirical evidence of our equilibria at an individual firm level

a foundation for markov equilibria in sequential games with finite social memory we study stochastic games with an infinite horizon and sequential moves played by an arbitrary number of players we assume that social memory is finite every player except possibly one is finitely lived and cannot observe events that are sufficiently far back in the past this class of games includes games between a long run player and a sequence of short run players and games with overlapping generations of players an equilibrium is purifiable if some close by behaviour is consistent with equilibrium when agents payoffs in each period are perturbed additively and independently we show that only markov equilibria are purifiable when social memory is finite thus if a game has at most one long run player all purifiable equilibria are markov

education returns across quantiles of the wage function alternative explanations for returns to education by race in south america private wage returns to schooling in south africa in 1993 are twice as high for nonwhites as for whites and substantially higher at advanced levels of schooling for both races to explore how these returns might be expected to change as the proportion of africans with secondary and higher education increases quantile regressions for the wage function are estimated for african males and white males if the residuals based on a standard wage function specification are interpreted as omitted ability and it is assumed that ability increases decreases returns to schooling then we expect quantile returns to increase decrease at higher quantiles this is not observed for africans at the higher and secondary school level but is evident among whites at higher educational levels the opposite pattern of differential returns favoring the least able i e lowest deciles is reported for the lower tail of the educational distribution that is for africans at the level of primary school and for whites at secondary school authors

a belief based approach to the repeated prisoners dilemma with asymmetric private monitoring abstract this paper extends the belief based approach to the repeated prisoners dilemma with asymmetric private monitoring we first find that the previous belief based techniques t sekiguchi efficiency in repeated prisoners dilemma with private monitoring j econ theory 76 1997 345 361 v bhaskar i obara belief based equilibria in the repeated prisoners dilemma with private monitoring j econ theory 102 2002 40 69 cannot succeed when players private monitoring technologies are sufficiently different we then modify the previous belief based approach by letting the player with smaller observation errors always randomize between cooperate and defect along the cooperative path of the play we show that with vanishing observation errors efficiency and a folk theorem can be approximated using our modified belief based strategies

individual learning and cooperation in noisy repeated games we investigate whether two players in a long run relationship can maintain cooperation when the details of the underlying game are unknown specifically we consider a new class of repeated games with private monitoring where an unobservable state of the world influences the payoff functions and or the monitoring structure each player privately learns the state over time but cannot observe what the opponent learned we show that there are robust equilibria in which players eventually obtain payoffs as if the true state were common knowledge and players played a belief free equilibrium we also provide explicit equilibrium constructions in various economic examples copyright 2014 oxford university press

does city structure affect job search and welfare we develop a model in which workers search efficiency is negatively affected by access to jobs workers location in a city is endogenous and reflects a trade off between commuting costs and the surplus associated with search different configurations emerge in equilibrium notably the unemployed workers may reside far away segregated city or close to jobs integrated city we prove that there exists a unique and stable market equilibrium in which both land and labor markets are solved for simultaneously we find that despite inefficient search in the segregated city equilibrium the welfare difference between the two equilibria is not so large due to differences in commuting costs we also show how a social planner can manipulate wages by subsidizing taxing the transport costs and can accordingly restore the efficiency

the folk theorem with imperfect public information the authors study repeated games in which players observe a public outcome that imperfectly signals the actions played they provide conditions guaranteeing that any feasible individually rational payoff vector of the stage game can arise as a perfect equilibrium of the repeated game with sufficiently little discounting the central condition requires that there exist action profiles with the property that for any two players no two deviations one by either player give rise to the same probability distribution over public outcomes the results apply to principal agent partnership oligopoly and mechanism design models and to one shot games with transferable utilities copyright 1994 by the econometric society

robustness of public equilibria in repeated games with private monitoring a repeated game with private monitoring is close to a repeated game with public monitoring or perfect monitoring when i the expected payoff structures are close and ii the informational structures are close in the sense that private signals in the private monitoring game can be aggregated by some public coordination device to generate a public signal whose distribution is close to the distribution of the public signal in the public monitoring game we provide a sufficient condition for the set of uniformly strict perfect public equilibria for a public monitoring game to be robust in nearby private monitoring games in the sense that they remain equilibria with respect to the public signal that is generated by such public coordination devices with truthful reporting our sufficient condition requires that every player is informationally small in a well defined sense

the economics of schooling production and efficiency in public schools n recent years public and professional interest in schools has been heightened by a spate of reports many of them critical of current school policy these policy documents have added to persistent and long standing concerns about the cost effectiveness and fairness of the current school structure and have made schooling once again a serious public issue as in the past however any renewed interest in education is likely to be short lived doomed to dissipate as frustration over the inability of policy to improve school practice sets in this frustration about school policy relates directly to knowledge about the educational production process and in turn to underlying research on schools although the educational process has been extensively researched clear policy prescriptions flowing from this research have been difficult to derive 2 there exists however a consistency to the research findings that does have an immediate application to school policy schools differ dramatically in quality

communication in repeated games with imperfect private monitoring this paper examines repeated games in which each player observes a private and imperfect signal on the actions played and in which players are allowed to communicate using public messages providing incentives for players to reveal their observations generates revelation constraints that combined with signal imperfections may be a source of inefficiencies however by delaying the revelation of their observations players may economize on the cost of deterring deviations and thereby avoid these inefficiencies because a player would not want to trigger a sanction that would penalize him too revelation constraints also tend to make sanctions difficult to enforce however with at least three players detecting deviations may not require that all the players reveal their observations in that case we obtain a nash threat version of the folk theorem with two players we do not obtain a similar result nevertheless we show that an efficient outcome can almost always be approximated

parental choice of human capital investment abstract in this paper we present a model in which parents make schooling decisions for their children we compare two educational regimes public and private education in the private education regime all human capital investment decisions are made by individuals under public education the government uses income tax revenue to finance one input to schooling in the private education regime cycles may occur even though there are constant returns to scale in the augmentable factors in the public education regime there are no cycles but poverty traps may occur

spatial mismatch and costly suburban commutes can commuting subsidies help proponents of the spatial mismatch hypothesis argue that job decentralisation harms low income residents of central cities because of barriers that limit their access to suburban labour markets such barriers can take the form of housing discrimination exclusionary zoning or long and difficult commutes this paper uses an urban equilibrium model of spatial mismatch to analyse the impact of commuting subsidies on the welfare of low income central city households with restricted mobility specifically it seeks to determine how effective such subsidies are at reducing the welfare impact of spatial mismatch while subsidised outward commuting is found to raise the welfare of the low income households the welfare gains are only a small portion of the welfare loss due to spatial mismatch

a robust folk theorem for the prisoner s dilemma we prove the folk theorem for the prisoner s dilemma using strategies that are robust to private monitoring from this follows a limit folk theorem when players are patient and monitoring is sufficiently accurate but private and possibly independent any feasible individually rational payoff can be obtained in sequential equilibrium the strategies used can be implemented by finite randomizing automata journal of economic literature classification numbers c72 c73 d82

testing present value models of the current account a cautionary note following campbell and shiller j pol eco 95 1987 1062 many papers have evaluated the intertemporal approach to the current account by testing restrictions on a vector autoregression var the attractiveness of the campbell shiller methodology is that it is thought to be immune to omitted information this paper shows that this is not always true in particular it is shown that if fundamentals are driven by unobserved to the econometrician permanent and transitory components then the restrictions of a standard present value model of the current account might not be testable with a var this is because the theoretical moving average representation can turn out to be non invertible this implies that observed data including the current account do not reveal the underlying shocks to agents information sets the paper shows how researchers employing the campbell shiller methodology can be tricked into thinking the current account responds excessively to shocks when in fact the data are consistent with the theory

school inputs and educational outcomes in south africa we examine the relationship between educational inputs primarily pupilteacher ratios and school outcomes in south africa immediately before the end of apartheid government black households were severely limited in their residential choice under apartheid and attended schools for which funding decisions were made centrally by white controlled entities over which they had no control the allocations resulted in marked disparities in average class sizes controlling for household background variables we find strong and significant effects of pupilteacher ratios on enrollment on educational achievement and on test scores for numeracy

equity and efficiency in human capital investment the local connection a general model of community formation and human capital accumulation with social spillovers and decentralized school funding is used to analyse the causes of economic segregation and its consequences for equity and efficiency significant polarization arises from minor differences in endowments preferences or access to capital markets this makes income inequality more persistent across generations but the same need not be true for wealth equilibrium stratification tends to be excessive resulting in low aggregate surplus whether state equalization of school resources can remedy these problems hinges on how purchased social and family inputs interact in education and in mobility decisions

are efficiency and equity in school finance substitutes or complements this paper analyzes cases made for local and centralized school finance and policies such as vouchers categorical aid and equalization aid an ideal system of school finance would achieve efficiency and equity by ensuring every person invests in the amount of schooling that is socially optimal for him the author evaluates the empirical evidence for and the merit and importance of arguments for each policy she concludes that the theoretical arguments for centralized finance not only exaggerate the efficiency equity tradeoff but actually make better arguments for a system combining local school finance with categorical aid and means tested vouchers

perfect communication equilibria in repeated games with imperfect monitoring this paper introduces an equilibrium concept called perfect communication equilibrium for repeated games with imperfect private monitoring this concept is a refinement of myerson s myerson r b 1982 optimal coordination mechanisms in generalized principal agent problems j math econ 10 67 81 communication equilibrium a communication equilibrium is perfect if it induces a communication equilibrium of the continuation game after every history of messages of the mediator we provide a characterization of the set of corresponding equilibrium payoffs and derive a folk theorem for discounted repeated games with imperfect private monitoring

community enforcement of trust with bounded memory we examine how trust is sustained in large societies with random matching when records of past transgressions are retained for a finite length of time to incentivize trustworthiness defaulters should be punished by temporary exclusion however it is profitable to trust defaulters who are on the verge of rehabilitation with perfect bounded information defaulter exclusion unravels and trust cannot be sustained in any purifiable equilibrium a coarse information structure that pools recent defaulters with those nearing rehabilitation endogenously generates adverse selection sustaining punishments equilibria where defaulters are trusted with positive probability improve efficiency by raising the proportion of likely re offenders in the pool of defaulters

a limit characterization of belief free equilibrium payoffs in repeated games abstract the present paper studies repeated games with private monitoring and characterizes the set of belief free equilibrium payoffs in the limit as the discount factor approaches one and the noise on private information vanishes contrary to the conjecture by ely et al j c ely j horner w olszewski belief free equilibria in repeated games econometrica 73 2005 377 415 the equilibrium payoff set is computed by the same formula no matter how many players there are as an application of this result a version of the folk theorem is established for n player prisoner s dilemma games

intergroup economic inequality in south africa the post apartheid era one of the most pressing challenges facing the south african government is how to expand the overall opportunity set for nonwhites who have been historically disadvantaged by apartheid this is perhaps best accomplished by expanding employment opportunities within the economy general employment expansion mnust be accomplished keeping in mind the urgent need to radically expand nonwhite employment employment and unemployment statistics are difficult to interpret but there is a general sense that the unemployment situation especially for nonwhites is extremely bad in dealing with employment issues two concerns must be faced both are legacies of the apartheid era the first is related to differences in educational attainment across racial groups during apartheid the bantu education policy was designed to suppress the educational attainment of africans blacks relative to whites however educational opportunities for coloureds mixed race and asians primarily indian were also depressed relative to whites the second concern is that labor market discrimination could be used either to exclude nonwhites for employment consideration or to limit their wages and opportunities once they are employed for policy reasons it is imperative to understand the extent to which premarket or market factors operate to limit opportunities for nonwhites given the institutionalized nature of apartheid segregation one can imagine three scenarios earnings differences could be the result entirely of premarket factors such as education differences alternatively earnings differences could be the result of labor market practices that limit one group s eamings relative to another s a third scenario a synthesis of the former two would find earnings differences to be the result of a combination of premarket differentials and in market discrimination to address premarket discrimination policy would focus entirely on leveling funding and increasing access to educational opportunities for historically disadvantaged groups however legislative forms such as affirmative action would be required to remedy exclusively labormarket discrimination a combination of these policies would be required to deal with the third scenario understanding the relative importance of these factors is important when resource allocation is considered this paper concerns itself with measuring income losses to nonwhites from labor market discrimination to evaluate the extent of labor market discrimination ordinary least squares ols estimates of earnings equations are evaluated for males in each population group observed wage differentials are decomposed into a component attributable to human capital differences while a residual is attributed to labor markelt discrimination these findings are then contrasted to those of others to give a sense of the trend in market discrimination in south africa

optimal cartel equilibria with imperfect monitoring abstract there exist optimal symmetric equilibria in the green porter model 4 8 having an elementary intertemporal structure such an equilibrium is described entirely by two subsets of price space and two quantities the only production levels used by firms in any contingency the central technique employed in the analysis is the reduction of the repeated game to a family of static games

introduction to repeated games with private monitoring abstract we present a brief overview of recent developments in discounted repeated games with imperfect private monitoring the literature explores the possibility of cooperation in a long term relationship where each agent receives imperfect private information about the opponents actions although this class of games admits a wide range of applications such as collusion under secret price cutting exchange of goods with uncertain quality and observation errors it has fairly complex mathematical structure due to the lack of common information shared by players this is in sharp contrast to the well explored case of repeated games under public information with the celebrated folk theorems and until recently little had been known about the private monitoring case however rapid developments in the past few years have revealed the possibility of cooperation under private monitoring for some class of games journal of economic literature classification numbers c72 c73 d43 d82 l13 l41

urban economic theory land use and city size this book examines the economic reasons why people choose to live where they live and develops through analysis of the bid rent function a unified theory of urban land use and city size the first part of the book explicates the basic theory of urban land use and optimal city size residential location behavior of households is examined in a microeconomic framework and equilibrium and optimal patterns of residential land use are discussed the corresponding equilibrium and optimal city sizes are studied in a variety of contexts part two extends the classical theories of von thunen and alonso with the addition of externality factors such as local public goods crowding and congestion and racial prejudice the rigorous mathematical approach and theoretical treatment of the material make urban economic theory of interest to researchers in urban economics location theory urban geography and urban planning

equilibrium and inefficiency in a community model with peer group effects public service output depends on input expenditures on own personal characteristics and on the characteristics of the other residents in the community the peer group effect in a community model with public expenditures set by voting with migration between communities and with land price differentials capitalization it is shown that communities may become heterogeneous in composition and second best inefficient this equilibrium occurs when the peer group effect is neither too strong nor too weak the inefficiency arises because an externality is created by migration the land price differential does not play the part of the price of the better peer group but of a transfer payment

the impact of school quality on earnings and educational returns evidence from a low income country abstract the expansion of education has been widely adopted as a key element in the development strategies of low income countries while there is substantial evidence on the benefits of greater educational attainment for subsequent labor market earnings empirical evidence on the role played by school quality is scarce this paper combines household survey data with unique data on school quality from honduras to study the importance of school quality as a determinant of earnings our objective measures of school quality capture teacher training school infrastructure and school crowding the results display strong positive effects of school quality on earnings and on educational returns these effects persist across a variety of model specifications

heterogeneity in returns to schooling econometric evidence from ethiopia this paper investigates whether returns to schooling in ethiopia vary across the wage distribution of individuals to do so it adopts an instrumental variables quantile regression framework that allows for both endogeneity of schooling resulting from unmeasured ability and possible heterogeneity in the impact of schooling the empirical estimates indicate that education contributes more to the earnings of individuals at a lower end of the income distribution

location and education in south african cities under and after apartheid we model a south african city during apartheid in which both schooling and mobility are restricted on the basis of race and after apartheid in which no restrictions are imposed we first show that the inequality between blacks and whites decreases when apartheid laws are removed indeed blacks are better off because of human capital externalities due to the possibility of mixing with white students whereas whites are worse off due to negative human capital externalities and intensified land market competition after apartheid we also show that reducing the commuting costs of black children always increases the utility of black families and may even increase that of whites

repeated games with private monitoring two players we investigate two player infinitely repeated games where the discount factor is less than but close to unity monitoring is private and players cannot communicate we require no condition concerning the accuracy of players monitoring technology we show the folk theorem for the prisoners dilemma with conditional independence we also investigate more general games where players private signals are correlated only through an unobservable macro shock we show that efficiency is sustainable for generic private signal structures when the size of the set of private signals is sufficiently large finally we show that cartel collusion is sustainable in price setting duopoly

changes in compulsory schooling education and the distribution of wages in europe using data from 12 european countries and the variation across countries and over time in the changes of minimum school leaving age we study the effects of the quantity of education on the distribution of earnings we find that compulsory school reforms significantly affect educational attainment especially among individuals belonging to the lowest quantiles of the distribution of ability there is also evidence that additional education reduces conditional wage inequality and that education and ability are substitutes in the earnings function

microeconomic uncertainties facilitate cooperative alliances and social welfare abstract we show that microeconomic chaotic variations of payoffs in the prisoner s dilemma game maintain cooperation over a broad range of defection temptation values where otherwise economic stalemate reigns thus unpredictability at micro scales impedes mutual defection that inflicts social poverty

local labor markets job matching and urban location we present a new way of modeling local labor markets by linking the space of workers skills and the physical space of cities the key lesson of our analysis is that firms exploit workers in these two spaces by setting wages that are below the competitive level the degree of monopsony power depends on the elasticity of the firm s labor pool which is inversely related to the costs workers incur in commuting and acquiring skills our analysis thus shows how socioeconomic ghettos emerge as workers with poor skill matches are also those who incur the highest commuting costs

the repeated prisoner s dilemma with imperfect private monitoring abstract in this paper i study a repeated prisoner s dilemma game in which monitoring is private and imperfect a partial folk theorem is proved for the case of almost perfect monitoring

private versus public schools in post apartheid south african cities theory and policy implications blacks and whites have different incomes decide where to locate in the city and which school to send their children to we show that despite the tuition fees imposed by whites and their remote location some black pupils attend the private school this market solution is shown not to be optimal because whites overprice education in order to limit black attendance at the private school three types of education policies are then considered transportation subsidies private school vouchers and public school spending the efficiency of such policies depends on the fee setting behavior of whites that strongly varies from one policy to another

belief based equilibria in the repeated prisoners dilemma with private monitoring abstract we analyze repeated prisoners dilemma games with imperfect private monitoring and construct mixed trigger strategy equilibria such strategies have a simple representation where a player s action only depends upon her belief that her opponent s are continuing to cooperate when monitoring is almost perfect the symmetric efficient outcome can be approximated in any prisoners dilemma game while every individually rational feasible payoff can be approximated in a class of such games the efficiency result extends when there are more than two players it requires that monitoring be sufficiently accurate but does not require very low discounting when a public randomization device is available journal of economic literature classification numbers c73 d82

educational homogamy positive assortative mating and income inequality in south africa an unconditional quantile regression analysis apart from being the first attempt at investigating the impact of education based homogamy and positive assortative mating on income inequality in a developing country context with very high levels

testing a present value model of the current account evidence from us and canadian time series abstract this paper presents a simple model of current account determination based upon the permanent income hypothesis of private consumption behavior under rational expectations the model employs a representative national agent who is forward looking and can borrow and lend at a constant world interest rate a present value relationship for the current account is derived and its implications are tested on post war data for the united states and canada testing is done using the framework developed by campbell and shiller 1987 which allows the forcing variables in the model to be difference rather than trend stationary our empirical results indicate the most stringent restrictions of the present value model are strongly rejected by the us and canadian data however less formal procedures suggest the consumption smoothing model has some ability to track the dynamic behavior of the us current account jel f32

flights towards defection in economic transactions we show that levy distributed variations of payoffs in the prisoner s dilemma game impede cooperation as the frequency of rare events increases levy flights thus facilitate defection but also uphold the evolutionary process arguably maintaining a healthy level of competitiveness amongst the agents

present value tests of an intertemporal model of the current account abstract this paper first demonstrates that in a simple intertemporal open economy model the current account is equal to the expected decline of the present discounted value of net output of a country net output is defined as gross domestic product less the sum of investment plus government spending it then uses econometric methods for present value models to analyze the current account for four countries in two of these countries the model does a satisfactory job of explaining the current account

effects of family and community background on economic status policy oriented discussions of poverty in the united states repeatedly have stressed the large influence of family and community background on income status in this paper we use a simple statistical model to explain how problems of measurement error and unrepresentative samples have caused previous statistical studies to underestimate the magnitude of background effects we then summarize a series of our own studies in which we have corrected for the biases in earlier studies and estimated substantially larger background effects the empirical analysis is based on data from the panel study of income dynamics excerpt

the folk theorem for repeated games with observation costs abstract the folk theorem literature has been relaxing the assumption on how much players know about each other s past action here we consider a general model where players can buy precise information every period each player decides whether to pay a cost to accurately observe the actions chosen by other players in the previous period when a player does not pay the cost he obtains only imperfect private signals observational decisions are unobservable to others known strategies such as trigger strategies do not work since they fail to motivate players to pay for information this paper shows that the folk theorem holds for any level of observation costs unlike existing folk theorems with private monitoring ours imposes virtually no restriction on the nature of costless imperfect signals the theorem does not use explicit or costless communication thereby having implications on antitrust laws that rely on evidence of explicit communication the main message is that accurate observation alone however costly enables efficient cooperation in general repeated games

efficiency in repeated prisoner s dilemma with private monitoring abstract this paper analyzes repeated games with private monitoring where in each period each player receives a signal of the other player s action in the previous period and that signal is private information previous literature on discounted repeated games with private monitoring has not shown whether or not nearly efficient equilibria exist for a repeated prisoner s dilemma satisfying a certain assumption regarding stage game payoffs we show that there exists a nearly efficient sequential equilibrium provided that imperfectness of signals is small and players are patient journal of economic literature classification number c73