micro vs macro explanations of post war us unemployment movements abstract this paper considers contributions of industry sectoral micro shocks vs aggregate macro shocks a dynamic factor model is estimated with maximum likelihood method in the frequency domain and decomposes us unemployment movements into industry sectoral and common components sectoral shocks account for around half unemployment movements

efficient diversification according to stochastic dominance criteria this paper develops the first operational tests of portfolio efficiency based on the general stochastic dominance sd criteria that account for an infinite set of diversification strategies the main insight is to preserve the cross sectional dependence of asset returns when forming portfolios by reexpressing the sd criteria int dimensional euclidean space with elements representing rates of return int different states of nature we characterize subsets of this state space that dominate a given evaluated return vector by first and second order sd this allows us to derive simple sd efficiency measures and test statistics computable by standard mathematical programming algorithms the sd tests and efficiency measures are illustrated by an empirical application that analyzes industrial diversification of the market portfolio

credit market imperfections and patterns of international trade and capital flows this paper offers two simple models to illustrate how corporate governance contractual enforcement and the balance sheet condition of the business sector etc can affect the patterns of international trade and capital flows in the presence of credit market imperfections jel d52 f15 f21 f40

a simple model of sectoral adjustment despite the significance of limited labour mobility across sectors few attempts have been made to produce dynamic models of sectoral adjustment which are consistent with perfect foresight and yet flexible enough to allow for a variety of dynamic experiments this paper proposes a simple perfect foresight model of two sector economies in which aggregate sectoral movement of labour takes place through the process of demographic change the model is tractable enough that one can easily examine the effects of intertemporally complicated relative price shocks both exogenous and endogenous under a variety of assumptions on technology

relative productivity and search unemployment in an open economy abstract using a panel of eighteen oecd countries we find empirically that the long run effects of higher productivity of tradables relative to non tradables vary across time space and stages of the business cycle more specifically our evidence reveals that elasticities of the relative wage and relative price of non tradables with respect to relative productivity of tradables increase over time our estimates also show that the fall in the relative wage is more pronounced whilst the appreciation in the relative price is less in countries where labor markets are more regulated and during periods of recession to rationalize the evidence we differentiate between labor mobility costs caused by job search efforts and hiring costs resulting from search frictions in the labor market in a two sector open economy model while time declining labor mobility costs can account for the time increasing effects of a productivity differential international differences in labor market regulation and variations of hiring costs across the business cycle respectively can rationalize the cross country and state dependent effects we estimate empirically finally labor market frictions have important implications for sectoral unemployment since labor mobility and hiring costs bias labor demand toward the traded sector which results in a greater decline in unemployment in tradables relative to unemployment in non tradables following higher relative productivity

social class and the spirit of capitalism one of the key social transformations that accompanied the british industrial revolution was the economic decline of the aristocracy standard theories of wealth inequality cannot explain why the aristocrats in spite of their superior wealth and education failed to be the main protagonists and beneficiaries of industrialization we discuss recent research based on a model of endogenous preferences that is consistent with the demise of aristocracy jel 010 040

negative moments risk aversion and stochastic dominance a simple moment ordering condition is shown to be necessary for stochastic dominance closely related results on generalizations of the geometric and harmonic means are also provided an ordering of the moment generating functions is shown to be necessary and sufficient for stochastic dominance the results have a straightforward and useful interpretation in terms of constant relative and absolute risk aversion utility functions these results are used to provide necessary and sufficient conditions for optimality of distributions on an important class of utility functions

the 2005 lawrence r klein lecture emergent class structure this article presents a model of the emergent class structure in which a society inhabited by inherently identical households may be endogenously split into the rich bourgeoisie and the poor proletariat for some parameter values the model has no steady state where all households remain equally wealthy in this case the model predicts emergent class structure or the rise of class societies even if every household starts with the same amount of wealth the society will experience symmetry breaking and will be polarized into two classes in steady state where the rich maintain a high level of wealth partly due to the presence of the poor who have no choice but to work for the rich at a wage rate strictly lower than the fair value of labor the nonexistence of the equal steady state means that a one shot redistribution of wealth would not be effective as wealth inequality and the class structure would always reemerge thus the class structure is an inevitable feature of capitalism for other parameter values on the other hand the model has the unique steady state which is characterized by perfect equality in this case the model predicts dissipating class structure or the fall of class societies even if the society starts with significant wealth inequality labor demand by the rich employers pushes up the wage rate so much that workers will escape from the poverty and eventually catch up with the rich eliminating wealth inequality and the class structure in the long run in an extension we introduce self employment which not only provides the poor with an alternative to working for the rich but also provides the rich with an alternative to investment that creates jobs due to this dual nature of self employment the effects of self employment turn out to be quite subtle yet within the present framework it is possible to offer a complete characterization of the steady states even in the presence of self employment

equilibrium income inequality among identical agents the paper offers a theory of income differences in which income inequality exists and persists despite identical tastes and talents teams of unskilled labor supervised by schooled managers produce goods with increasing returns to scale agents are assumed unable to borrow to fund the human capital investment needed to become managers despite ex ante identical agents the model displays the following equilibrium phenomena i risk averse agents accept fair gambles implying an unequal ex post distribution of unearned income ii agents agree to publicly subsidize education although those receiving the subsidy have the highest material wealth and iii income and educational differences are perpetuated from generation to generation

frontier based vs traditional mutual fund ratings a first backtesting analysis we explore the potential benefits of a series of existing and new non parametric convex and non convex frontier based fund rating models to summarize the information contained in the moments of the mutual fund price series limiting ourselves to the traditional mean variance portfolio setting we test in a simple backtesting setup whether these efficiency measures fare any better than more traditional financial performance measures in selecting promising investment opportunities the evidence points to a remarkable superior performance of these frontier models compared to most but not all traditional financial performance measures

dynamic portfolio selection with fixed and or proportional transaction costs using non singular stochastic optimal control theory abstract the dynamic portfolio selection problem with fixed and or proportional transaction costs is studied the portfolio consists of a risk free asset and a risky asset whose price dynamics is governed by geometric brownian motion the objective is to find the amounts invested in the risk free and risky assets that maximize the expected value of the discounted utility of terminal wealth the dynamic optimization problem is formulated as a non singular stochastic optimal control problem numerical results are presented for buy and sell no transaction interfaces and buy and sell targets that characterize the optimal policies of a constant relative risk aversion investor

used clothing donations and apparel production in africa this article examines the importance of one possible explanation for the failure of african countries to step onto the bottom rung of the manufacturing sophistication ladder that is to produce apparel used clothing donations to thrift shops and other organisations in industrialised countries typically end up being sold to consumers in africa since used clothing is initially provided as a donation it shares characteristics with food aid which always assists consumers but at times harms african food producers used clothing imports are found to have a negative impact on apparel production in africa explaining roughly 40 of the decline in production and 50 of the decline in employment over the period 1981 2000

foundations of portfolio theory prize lecture to the memory of alfred nobel december 7 1990 this abstract was borrowed from another version of this item

openness and income the roles of trade and migration abstract this paper explores the relationship between openness to trade immigration and income per person across countries to address endogeneity concerns we extend the instrumental variables strategy introduced by frankel and romer 1999 we build predictors of openness to immigration and to trade for each country by using information on bilateral geographical and cultural distance while controlling for country size since geography may affect income through other channels we also control for climate disease environment natural resources and colonial origins most importantly we also account for the roles of institutions and early development our instrumental variables estimates provide evidence of a robust positive effect of openness to immigration on long run income per capita in contrast we are unable to establish an effect of trade openness on income we also show that the effect of migration operates through an increase in total factor productivity which appears to reflect increased diversity in productive skills and to some extent a higher rate of innovation

the global economic crisis and the effect of immigrant workers on native born employment in europe the debate regarding the economic effects of employing immigrants has attracted renewed interest in european countries since the economic crisis we provide an approximation of the labour market effects of immigrant workers in four european countries during the global economic crisis after briefly analysing native and foreign born worker conditions for the most recent period our analysis focuses on the correlation between the stock of immigrant workers and the number of native labour market workers across several segments of the labour market using a simple model approach using eurostat and lfs labour force survey data we estimate a structural dynamic model using the generalised method of moments gmm to examine adjustment dynamics in the labour market and labour market segment and worker educational levels countries of origin and genders overall the empirical results suggest that immigrant labour force effects on native born worker employment rates have been persistent and but weak throughout the business cycle these effects are globally positive and immigrant origins do not appear to change the nature of their impact we offer some explanations for these findings related to dual labour markets and to differences in levels of substitution among native and immigrant workers

growing through cycles in an infinitely lived agent economy abstract this paper extends the analysis of k matsuyama econometrica67 1999 335 347 to the case of an infinitely lived representative agent economy the economy grows endogenously through endogenous fluctuations perpetually moving back and forth between two phases in one phase there is no innovation the market structure is competitive and the economy grows solely by capital accumulation in the other phase new goods are introduced and the market structure is monopolistic in the long run both investment and innovation grow at the same rate but the economy alternates between the periods of high investment and the periods of higher innovation journal of economic literature classification numbers e32 o11

efficient use of information and social value of information this paper analyzes equilibrium and welfare for a tractable class of economies games that have externalities strategic complementarity or substitutability and heterogeneous information first we characterize the equilibrium use of information complementarity heightens the sensitivity of equilibrium actions to public information raising aggregate volatility whereas substitutability heightens the sensitivity to private information raising cross sectional dispersion next we define and characterize an efficiency benchmark designed to address whether the equilibrium use of information is optimal from a social perspective the efficient use of information reflects the social value of aligning choices across agents finally we examine the comparative statics of equilibrium welfare with respect to the information structure the social value of information is best understood by classifying economies according to the inefficiency if any in the equilibrium use of information we conclude with a few applications including production externalities beauty contests business cycles and large cournot and bertrand games

parental altruism and inter vivos transfers theory and evidence this paper uses psid data on the extended family to test whether inter vivos transfers from parents to children are motivated by altruism specifically the paper tests whether an increase by one dollar in the income of parents actively making transfers to a child coupled with a one dollar reduction in that child s income results in the parents increasing their transfer to the child by one dollar this restriction on parental and child transfer income derivatives is derived for the standard altruism model augmented to include uncertainty and liquidity constraints these additional elements pin down the timing of inter vivos transfers the method used to estimate income transfer derivatives takes into account unobserved heterogeneity across families in the degree of altruism the findings strongly reject the altruism hypothesis redistributing one dollar from a recipient child to donor parents leads to less than a 13 cent increase in the parents transfer to the child far less than the one dollar increas

borrow and adjust fiscal policy and sectoral adjustment in an open economy should the government run fiscal deficits in response to an adverse external shock that warrants transfer of resources from production of nontraded to traded goodsq this article considers normative fiscal policy implications of sectoral adjustment costs in a two sector model with overlapping generations fiscal deficits benefit present generations by depleting foreign assets and slowing down the adjustment process we show that despite no nominal rigidities temporary fiscal deficits increase social welfare if adjustment costs prevent immediate sectoral reallocation of inputs if there are no adjustment costs the case for fiscal deficits vanishes copyright 2003 by the economics department of the university of pennsylvania and osaka university institute of social and economic research association

immigration and inequality immigration is often viewed as a proximate cause of the rising wage gap between highand low skilled workers nevertheless there is controversy over the appropriate theoretical and empirical framework for measuring the presumed effect and over the precise magnitudes involved this paper offers an overview and synthesis of existing knowledge on the relationship between immigration and inequality focusing on evidence from cross city comparisons in the u s while some researchers have claimed that a cross city research design is inherently flawed i argue that the evidence from cross city comparisons is remarkably consistent with recent findings based on aggregate time series data in particular cross city and aggregate time series comparisons provide support for three key conclusions 1 workers with below high school education are perfect substitutes for those with a high school education 2 high school equivalent and college equivalent workers are imperfect substitutes with an elasticity of substitution on the order of 2 3 within education groups immigrants and natives are imperfect substitutes together these results imply that the average impacts of recent immigrant inflows on the relative wages of u s natives are small the effects on overall wage inequality including natives and immigrants are larger reflecting the concentration of immigrants in the tails of the skill distribution and higher residual inequality among immigrants than natives even so immigration accounts for a small share 5 of the increase in u s wage inequality between 1980 and 2000

low and high skill migration flows free mobility versus other determinants we investigate what economic factors drive international migration of workers to france and how their influence varies across different skill levels under restrictive policies and through time as free mobility is implemented we find that neither incentives nor policy parameters are similar across skill levels migration drivers such as a network of compatriots and relative incomes influence the movement of low skill workers high skill individuals however move only according to financial opportunities be they standard of living or returns to skill within a class we conclude that competition for high skill workers among organization for economic co operation and development oecd countries requires more than free mobility to successfully attract high skill migrants even for a developed country such as france

precautionary saving in the small and in the large the theory of precautionary saving is shown to be isomorphic to the arrow pratt theory of risk aversion making possible the application of a large body of knowledge about risk aversion to precautionary saving and more generally to the theory of optimal choice under risk in particular a measure of the strength of the precautionary saving motive analogous to the arrow pratt measure of risk aversion is used to establish a number of new propositions about precautionary saving and to give a new interpretation of the dreze modigliani substitution effect copyright 1990 by the econometric society

export diversification through resource based industrialization the case of natural gas for small resource rich developing economies specialization in raw exports is usually considered to be detrimental to growth and resource based industrialization rbi is often advocated to promote export diversification this paper develops a new methodology to assess the performance of these rbi policies we first formulate an adapted mean variance portfolio model that explicitly takes into consideration i a technology based representation of the set of feasible export combinations and ii the cost structure of the resource processing industries second we provide a computationally tractable reformulation of the resulting mixed integer nonlinear optimization problem finally we present an application to the case of natural gas comparing current and efficient export oriented industrialization strategies of nine gas rich developing countries

sorting it out international trade with heterogeneous workers each worker brings a bundle of skills to the workplace for example quantitative and communication skills since employers must take this bundle as a package deal they choose workers with just the right mix of skills we show that international differences in the distribution of worker skill bundles for example japan s abundance of workers with a modest mix of both quantitative and teamwork skills have important implications for international trade industrial structure and domestic income distribution formally we model two dimensional worker heterogeneity and show that the second moments of the distribution of skills are critical as in the roy model

location scale portfolio selection with factor recentered skew normal asset returns abstract this paper analyzes the single period portfolio selection problem on the location scale return family the skew normal distribution after recentering and reparameterization is shown to be in this family the recentered and reparameterized distribution called factor recentered skew normal can be expressed as a skew factor model which is characterized by a location parameter and two scale parameters risk preference on scale parameter is non monotonic and risk averse investors prefer larger smaller scale when the scale is negative positive the three parameter efficient set is a part of conical surface bounded by two lines positive skewness portfolios and negative skewness portfolios do not coexist in the efficient set numerical cases under constant absolute risk aversion are analyzed with its closed form certainty equivalent an asset pricing formula which nests the capm is obtained

a theory of disappointment aversion an axiomatic model of preferences over lotteries is developed it is shown that this model is consistent with the allais paradox includes expected utility theory as a special case and is only one parameter beta richer than the expected utility model allais paradox type behavior is identified with positive values of beta preferences with positive beta are said to be disappointment averse it is shown that risk aversion implies disappointment aversion and that the arrow pratt measures of risk aversion can be generalized in a straight forward manner to the current framework copyright 1991 by the econometric society

individual attitudes towards skilled migration an empirical analysis across countries it is commonly argued that skilled immigration benefits the destination country through several channels yet only a limited number of countries report having policies in place aimed at increasing the intake of skilled immigrants why in this paper we analyse the factors that affect a direct measure of individual attitudes towards skilled migration we focus on two main channels the labour market and the welfare state we find that more educated natives are less likely to favour skilled immigration consistent with the labour market channel while richer people are more likely to do so in accordance with the welfare state channel under the tax adjustment model our findings thus suggest that the labour market competition threat perceived by skilled natives in the host countries might be driving the observed cautious policies

asset pricing in a generalized mean lower partial moment framework theory and evidence a new asset pricing model that generalizes earlier results in the downside risk literature is developed and empirically tested using a multivariate approach by specifying risk as deviations below any arbitrary target rate of return the generalized mean lower partial moment mlpm model overcomes the limited appeal of earlier formulations and moreover a large class of extant pricing models using alternative risk measures variance semivariance semideviation probability of loss etc becomes special cases of the new framework empirical tests indicate that the new model cannot be rejected against an unspecified alternative for a large set of target rates of return the traditional capm on the other hand is rejected as a well specified alternative the mlpm target rates inferred from market data appear to be related to equity market mean returns rather than to the riskfree rate the target rate that is implicit in the capm and explicit in earlier downside risk formulations the attractiveness of downside risk measures for decision making purposes has been noted in the financial economic literature for over a quarter of a century 1 risk from this perspective is measured in terms of deviations below some exogenously prespecified target rate of return and a formal analysis of these risk measures for various utility functions has been presented by bawa 1975 in terms of the lower partial moment lpm of the asset distributions the appeal of these risk measures has been based in part on their consistency with the way individuals actually perceive risk notwithstanding its intuitive appeal this area of research has been virtually neglected in recent years we believe that this disaffection with downside risk models tends from two sources first earlier models of this genre exogenously specify the target rate to equal the risk free interest rate in the absence of a satisfactory theory for explaining how investors establish their target rates this assumption as argued herein has been motivated more by technical reasons than economic considerations second empirical tests

endogenous ranking and equilibrium lorenz curve across ex ante identical countries this paper proposes a symmetry breaking model of trade with a large but finite number of ex ante identical countries and a continuum of tradeable goods which differ in their dependence on local differentiated producer services productivity differences across countries arise endogenously through free entry to the local service sector in each country in any stable equilibrium the countries sort themselves into specializing in different sets of tradeable goods and a strict ranking of countries in per capita income tfp and the capital labor ratio emerges endogenously furthermore the distribution of country shares the lorenz curve is unique and analytically solvable in the limit as the number of countries grows unbounded using this limit as an approximation allows us to study what determines the shape of distribution to perform various comparative statics and to evaluate the welfare effects of trade publication abstract

is equality stable economic inequality is of interest not only at some intrinsic level but also for its close connections to diverse variables ranging from economic indicators such as growth rates to sociopolitical outcomes such as collective action and conflict it is only natural then to study the evolution of inequality in an economic system it is fair to say that the dominant view on this topic is that inequality is the outcome of a constant battle between convergence and luck gary becker and nigel tomes 1979 current asset inequalities may echo into the future but their natural tendency is to die out owing to a convex investment technology disparities are only sustained through ongoing stochastic shocks see also david champernowne 1953 glenn loury 1981 a second approach emphasizes that initial conditions determine final outcomes owing principally to a nonconvex investment technology see e g mukul majumdar and tapan mitra 1982 abhijit banerjee and andrew newman 1993 oded galor and joseph zeira 1993 ray and peter streufert 1993 historical disparities may persist and magnify if such differences straddle some bifurcation threshold inequality is not inevitable in this view stable steady states with inequality coexist with others that involve perfect equality in this paper we examine a third view which emphasizes an intrinsic tendency of the market mechanism to create inequality in this approach economic inequality appears as an inevitable outcome even if all agents are identical to begin with and even if there is no uncertainty or technological nonconvexity this view has received attention in ray 1990 debasis bandyopadhyay 1993 lars ljungqvist 1993 scott freeman 1996 kiminori matsuyama 2001 and mookherjee and ray 2001 the basic argument is as follows suppose that an economy is populated by several dynasties each of which allocates resources to current consumption and bequests to descendants assume for the moment that the latter consists entirely of educational expenditures preparing children for their chosen professions of course the returns to such professions are endogenous they depend on the distribution of individuals across different professions now if several professional categories are necessary wages must adjust so as to force separation in choices even if all individuals are ex ante identical to be sure this broken symmetry matsuyama 2002 has no payoff implications for the generation alive today identical individuals must receive identical payoffs starting with the next generation however there must be inequality not just in wages but in payoffs there must be individuals in lowpaying professions that involve low training costs whose parents invested little and there must be others in high paying high trainingcost professions whose parents invested a lot once such inequality sets in it may well magnify richer offspring will find it easier to invest in better paying professions for their children two ingredients are used in this argument first credit markets must be missing or imperfect otherwise the necessary finances may be borrowed and wages net of costs must be equalized over all professions however the assumption that parents cannot borrow against their children s future earnings seems innocuous enough second parents cannot make financial bequests to supplement or substitute for educational expenditures such bequests could conceivably neutralize earnings inequality this motivates the question when might financial bequests compensate for earnings inequality in steady state moreover starting from perfect equality will equality be preserved thereafter or will inequality emerge and persist we discuss an extended example from an ongoing research project mookherjee department of economics boston university 270 bay state road boston ma 02215 ray department of economics new york university 269 mercer street new york ny 10003 and instituto de analisis economico csic barcelona spain we thank kiminori matsuyama who encouraged us to write this paper

monetary policy with sectoral trade offs we formulate a two sector new keynesian economy that features sectoral heterogeneity along three main dimensions price stickiness consumption goods durability and the inter sectoral trade of input materials the combination of these factors deeply affects inter sectoral and intra sectoral stabilization in this context we examine the welfare properties of simple rules that adjust the policy rate in response to the output gap and alternative measures of final goods price inflation aggregating durable and non durable goods prices depending on the relative frequency of sectoral price setting may induce a severe bias due to factor demand linkages the cost of production in one sector is influenced by price setting in the other sector of the economy as a result measures of aggregate inflation that weigh sectoral price dynamics based on the relative degree of price rigidity do not allow the central bank to keep track of the effective speeds of sectoral price adjustment

financial market globalization symmetry breaking and endogenous inequality of nations this paper investigates the effects of financial market globalization on the inequality of nations the world economy consists of inherently identical countries which differ only in their levels of capital stock each country is represented by the standard overlapping generations model modified only to incorporate credit market imperfection an integration of financial markets affects the set of stable steady states as it changes the balance between the equalizing force of the diminishing returns technology and the unequalizing force of the wealth dependent borrowing constraint the model is tractable enough to allow for a complete characterization of the stable steady states in the absence of the international financial market the world economy has a unique steady state which is symmetric and stable in the presence of the international financial market symmetry breaking occurs under some conditions that is the symmetric steady state loses its stability and stable asymmetric steady states come to exist in the stable asymmetric steady states the world economy is endogenously divided into the rich and poor countries the borrowing constraints are binding in the poor but not in the rich the world output is smaller the rich are richer and the poor are poorer in any of the stable asymmetric steady states than in the unstable symmetric steady state

a risk return model with risk and return measured as deviations from a target return two attribute risk and return models are very popular in the economics and finance literature for analyzing decisions under uncertainty their popularity stems primarily from the intuitive appeal of the dichotomy into risk and return and from the ease with which the concepts can be diagrammed in two dimensions the most commonly used risk return model is the mean variance model in which risk is measured as the variance and return by the mean of the probability distribution over outcomes the mean variance model has a number of shortcomings which are widely known but of particular concern here are the facts that 1 mean variance dominance is neither necessary nor sufficient for second degree stochastic dominance 2 unless the form of the probability distribution is restricted mean variance is consistent with von neumann morgenstern utility theory only if the utility function is quadratic and 3 as peter fishburn has noted

short run and long run in trade models a note abstract this paper aims to capture key features of the ricardo viner rv and heckscher ohlin ho theories in a single dynamic general equilibrium framework we use a simple 2 sector 2 factor model with adjustment costs associated with the movement of capital across sectors we analyze the economy s response to exogenous changes in factor endowments and output prices our model reproduces the predictions of the rv theory in the short run moment immediately after a parameter change and the predictions of the ho model in the long run steady state implied by a new set of parameters numerical examples of transition paths are also provided

portfolio selection in multidimensional general and partial moment space abstract this paper develops a general approach for the single period portfolio optimization problem in a multidimensional general and partial moment space a shortage function is defined that looks for possible increases in odd moments and decreases in even moments a main result is that this shortage function ensures sufficient conditions for global optimality it also forms a natural basis for developing tests on the influence of additional moments furthermore a link is made with an approximation of an arbitrary order of a general indirect utility function this non parametric efficiency measurement framework permits to differentiate mainly between portfolio efficiency and allocative efficiency finally information can in principle be inferred about the revealed risk aversion prudence temperance and other higher order risk characteristics of investors

data envelopment analysis models of investment funds abstract this paper develops theory missing in the sizable literature that uses data envelopment analysis to construct return risk ratios for investment funds it explores the production possibility set of the investment funds to identify an appropriate form of returns to scale it discusses what risk and return measures can justifiably be combined and how to deal with negative risks and identifies suitable sets of measures it identifies the problems of failing to deal with diversification and develops an iterative approximation procedure to deal with it it identifies relationships between diversification coherent measures of risk and stochastic dominance it shows how the iterative procedure makes a practical difference using monthly returns of 30 hedge funds over the same time period it discusses possible shortcomings of the procedure and offers directions for future research

the labour market impact of immigration in the first part of this paper we present a stylized model of the labour market impact of immigra tion we then discuss mechanisms through which an economy can adjust to immigration changes in factor prices output mix and production technology in the second part we explain the problems of empirically estimating how immigration affects labour market outcomes of the resident population and review some strategies to address these we then summarize some recent empirical studies for the uk and other countries we conclude with an outlook on what we believe are important avenues for future research

occupational choice and the process of development this paper models economic development as a process of institutional transformation by focusing on the interplay between agents occupational decisions and the distribution of wealth because of capital market imperfections poor agents choose working for a wage over self employment and wealthy agents become entrepreneurs who monitor workers only with sufficient inequality however will there be employment contracts otherwise there is either subsistence or self employment thus in static equilibrium the occupational structure depends on distribution since the latter is itself endogenous we demonstrate the robustness of this result by extending the model dynamically and studying examples in which initial wealth distributions have long run effects in one case the economy develops either widespread cottage industry self employment or factory production employment contracts depending on the initial distribution in the other example it develops into prosperity or stagnation

expected utility asset allocation most asset allocation analyses use the mean variance approach for analyzing the trade off between risk and expected return analysts use quadratic programming to find optimal asset mixes and the characteristics of the capital asset pricing model to determine reasonable optimization inputs this article presents an alternative approach in which the goal of asset allocation is to maximize expected utility where the utility function may be more complex than that associated with mean variance analysis inputs for the analysis are based on the assumption of asset prices that would prevail if there were a single representative investor who desired to maximize expected utility

non parametric frontier estimates of mutual fund performance using c and l moments some specification tests there is a burgeoning literature using non parametric frontier methods to measure mutual fund performance these articles measure the relationship between the various characteristics mainly return information and some costs of ownership of these specialized financial products to establish a ranking using some efficiency measure we argue in favor of the use of the shortage function which is compatible with general investor preferences and question some of the often maintained hypotheses in this line of research the empirical part employs a large database of us and european mutual funds to offer extensive tests of the underlying modeling assumptions using various frontier estimators

resampling dea estimates of investment fund performance abstract data envelopment analysis dea is attractive for comparing investment funds because it handles different characteristics of fund distribution and gives a way to rank funds there is substantial literature applying dea to funds based on the time series of funds returns this article looks at the issue of uncertainty in the resulting dea efficiency estimates investigating consistency and bias it uses the bootstrap to develop stochastic dea models for funds derive confidence intervals and develop techniques to compare and rank funds and represent the ranking it investigates how to deal with autocorrelation in the time series and considers models that deal with correlation in the funds returns

urban growth and transportation we estimate the effects of interstate highways on the growth of u s cities between 1983 and 2003 we find that a 10 increase in a city s initial stock of highways causes about a 1 5 increase in its employment over this 20 year period to estimate a structural model of urban growth and transportation we rely on an instrumental variables estimation that uses a 1947 plan of the interstate highway system an 1898 map of railroads and maps of the early explorations of the u s as instruments for 1983 highways we investigate the role of interstate highways in the growth of u s cities our investigation is in three parts in the first we develop a simple structural model describing the joint evolution of highways and employment in cities in the second we develop an instrumental variables strategy that allows us to identify key parameters of our structural model we are also able to provide out of sample evidence for the validity of our estimates and for the central assumptions of our model in the third we use our estimates to assess counterfactual transportation policies we find that a 10 increase in a city s stock of interstate highways causes about a 1 5 increase in its employment over 20 years and that an additional kilometre of highway allocated to a city at random is associated with a larger increase in employment or population than is a road assigned to a city by the prevailing political process our results also suggest that too many new highways were built between 1983 and 2003 these findings are important for three reasons first transportation generally and infrastruc ture in particular are large segments of the economy the median u s household devotes about 18 of its income to road transportation while all levels of government together spend another 200 billion dollars annually overall the value of capital stock associated with road transporta tion in the u s tops 5 trillion dollars united states bureau of transportation statistics 2007 2010 given the magnitude of transportation expenditures it is important that the impact of these expenditures on economic growth be carefully evaluated and not assessed on the basis of the claims of advocacy groups our analysis provides a basis for assessing whether these resources are well allocated our results also provide useful guidance to policy makers charged with planning cities since changes in a city s transportation infrastructure cause changes to the city s employment new transportation infrastructure causes complementary changes in the demand for public utilities and schools our results provide a basis for estimating the magnitude of such changes finally this research is important to furthering our understanding of how cities operate and grow transportation costs are among the most fundamental quantities in theoretical models

technological change technological catch up and capital deepening relative contributions to growth and convergence we decompose labor productivity growth into components attributable to 1 technological change shifts in the world production frontier 2 technological catch up movements toward or away from the frontier and 3 capital accumulation movement along the frontier the world production frontier is constructed using deterministic methods requiring no specification of functional form for the technology nor any assumption about market structure or the absence of market imperfections we analyze the evolution of the cross country distribution of labor productivity in terms of the tripartite decomposition finding that technological change is decidedly nonneutral and that both growth and bipolar international divergence are driven primarily by capital deepening jel o30 o47 d24

least squares learning and the stability of equilibria with externalities this paper studies the stability of competitive equilibria in a model of aggregate employment when the representative agent uses a least squares forecasting procedure it is shown that the pareto inferior low employment steady state is always unstable under least squares learning even if it is stable under perfect foresight the high employment steady state is stable under learning if and only if it is saddle point stable under perfect foresight this weakens multiple equilibrium theories of coordination failure that purport to explain persistently high unemployment the pareto superior high employment steady state will be the focal point of individual forecasting

current account dynamics in a finite horizon model abstract this paper examines the response of the current account in a small open economy to a permanent change in the price of imported intermediate goods to do so it extends blanchard s 1985 open economy model to incorporate the capital stock with adjustment costs a la hayashi 1982 a price increase in imported intermediate goods can be viewed as a combination of transfer payments abroad and capital taxation the former effect leads to a current account deficit and the latter leads to a current account surplus the overall effect depends on the relative magnitude of these effects

isolating the network effect of immigrants on trade within the migration trade nexus literature this paper proposes a more carefully defined measure of migration business networks and quantifies its impact on bilateral trade using cross sectional data and controlling for the overall bilateral stock of migrants the share of migrants employed in managerial business related occupations has a strong additional effect on trade those immigrants should be the ones directly involved in the diffusion and transmission of information relevant for companies trading with other countries their presence is found to increase the volume of trade especially of imports beyond the already known effect of immigrants or highly educated immigrants when we control for the presence of highly educated immigrants the share of immigrants in business network occupations shows a particularly large effect on trade in differentiated goods we also find that highly educated individuals in business related occupations are those contributing to stimulate import and export by the largest margin business network effects seem particularly important in stimulating exports to culturally different countries such as those with different language and legal origin

effects of innovation on employment a dynamic panel analysis abstract this paper estimates the effect of innovation on employment at the firm level our uniquely long innovation panel data set of german manufacturing firms covers more than 20 years and allows us to use various innovation measures we can distinguish between product and process innovations as well as between innovation input and innovation output measures using dynamic panel gmm system estimation we find positive effects of innovation on employment this is true for innovation input as well as for innovation output variables innovations show their positive effect on employment with a time lag and process innovations have higher effects than product innovations

identifying earnings assimilation of immigrants under changing macroeconomic conditions failure to account for differences between immigrants and natives in their responsiveness to changes in macroeconomic conditions may bias estimates of assimilation effects on immigrant earnings using norwegian register data from 1980 to 1996 we first establish that earnings of immigrants from non oecd countries exhibit greater sensitivity to local unemployment than do earnings of natives the empirical analysis further reveals that standard methods of estimation which fail to consider differential immigrant and native responsiveness understate earnings growth and overstate cohort differentials among non oecd immigrants these biases are attributable to trends in macroeconomic conditions over the sample period

mean variance skewness portfolio performance gauging a general shortage function and dual approach this paper proposes a nonparametric efficiency measurement approach for the static portfolio selection problem in mean variance skewness space a shortage function is defined that looks for possible increases in return and skewness and decreases in variance global optimality is guaranteed for the resulting optimal portfolios we also establish a link to a proper indirect mean variance skewness utility function for computational reasons the optimal portfolios resulting from this dual approach are only locally optimal this framework permits to differentiate between portfolio efficiency and allocative efficiency and a convexity efficiency component related to the difference between the primal nonconvex approach and the dual convex approach furthermore in principle information can be retrieved about the revealed risk aversion and prudence of investors an empirical section on a small sample of assets serves as an illustration

policy designs in a dynamic model of infant industry protection abstract this paper takes the neoclassical infant industry model allows agents to respond to future expectations and reveals previously unexplained relationships between protection and outcome policy which projects to protect the industry until international competitiveness may not necessarily succeed consistent to the mixed empirical evaluations to guarantee success protection has to last longer however for success to be an equilibrium protection can last shorter decline after take off is also an equilibrium when adjustment speed is bounded increasing the protection rate is not isomorphic to decreasing its duration in policy design adjustment speed critical industry scale and policy duration are all relevant

growing through cycles the neoclassical growth model focuses on factor accumulation as an engine of growth while the neo schumpetarian growth model stresses innovation this paper argues that these two views of growth may capture different phases of a single growth experience in the model presented below the balanced growth path is unstable and the economy achieves sustainable growth through cycles under an empirically plausible condition perpetually moving back and forth between two phases one phase is characterized by higher output growth higher investment no innovation and a competitive market structure the other phase is characterized by lower output growth lower investment high innovation and a more monopolistic market structure both investment and innovation are essential in sustaining growth indefinitely and yet they move in an asynchronized way only one of them appears to play a dominant role in each phase the economy grows faster along the cycles than along the unstable balanced growth path

employment wages and the economic cycle differences between immigrants and natives in this paper we analyse differences in the cyclical pattern of employment and wages of immigrants and natives for two large immigrant receiving countries germany and the uk we show that despite large differences in their immigrant populations there are similar and significant differences in cyclical responses between immigrants and natives in both countries even conditional on education age and location we decompose changes in outcomes into a secular trend and a business cycle component we find significantly larger unemployment responses to economic shocks for low skilled workers relative to high skilled workers and for immigrants relative to natives within the same skill group there is little evidence for differential wage responses to economic shocks we offer three explanations for these findings an equilibrium search model where immigrants experience higher job separation rates a model of dual labour markets and differences in the complementarity of immigrants and natives to capital

imperfect factor mobility and the distribution of income abstract when labor is imperfectly mobile between industries workers may have a special interest in commercial policies that increase the price of the output of the industry in which they are employed this proposition is investigated in a two good model in which the degree of labor mobility is measured by the elasticity of a convex input transformation curve the existence of such a transformation curve is justified by a model in which individual workers have differing relative and absolute efficiencies in different industries the results are extended to the case of many industries

the labor market impact of immigration in western germany in the 1990 s in this article we estimate the wage and employment effects of recent immigration in western germany using administrative data for the period 1987 2001 and a labor market equilibrium model we find that the substantial immigration of the 1990s had very little adverse effects on native wages and on their employment levels instead it had a sizeable adverse employment effect on previous immigrants as well as a small adverse effect on their wages these asymmetric results are partly driven by a higher degree of substitution between old and new immigrants in the labor market and in part by the rigidity of wages in less than flexible labor markets in a simple counter factual experiment we show that in a world of perfect wage flexibility and no unemployment insurance the wage bill loss of old immigrants would be much smaller

conditional volatility skewness and kurtosis existence persistence and comovements abstract recent portfolio choice asset pricing value at risk and option valuation models highlight the importance of modeling the asymmetry and tail fatness of returns these characteristics are captured by the skewness and the kurtosis we characterize the maximal range of skewness and kurtosis for which a density exists and show that the generalized student t distribution spans a large domain in the maximal set we use this distribution to model innovations of a garch type model where parameters are conditional after demonstrating that an autoregressive specification of the parameters may yield spurious results we estimate and test restrictions of the model for a set of daily stock index and foreign exchange returns the estimation is implemented as a constrained optimization via a sequential quadratic programming algorithm adequacy tests demonstrate the importance of a time varying distribution for the innovations in almost all series we find time dependency of the asymmetry parameter whereas the degree of freedom parameter is generally found to be constant over time we also provide evidence that skewness is strongly persistent but kurtosis is much less so a simulation validates our estimations and we conjecture that normality holds for the estimates in a cross section setting we also document covariability of moments beyond volatility suggesting that extreme realizations tend to occur simultaneously on different markets

a theory of trickle down growth and development this paper develops a model of growth and income inequalities in the presence of imperfect capital markets and it analyses the trickle down effect of capital accumulation moral hazard with limited wealth constraints on the part of the borrowers is the source of both capital market imperfections and the emergence of persistent income inequalities three main conclusions are obtained from this model first when the rate of capital accumulation is sufficiently high the economy converges to a unique invariant wealth distribution second even though the trickle down mechanism can lead to a unique steady state distribution under laissez faire there is room for government intervention in particular redistribution of wealth from rich lenders to poor and middle class borrowers improves the production efficiency of the economy both because it brings about greater equality of opportunity and also because it accelerates the trickle down process third the process of capital accumulation initially has the effect of widening inequalities but in later stages it reduces them in other words this model can generate a kuznets curve

measuring international skilled migration a new database controlling for age of entry recent data on international migration of skilled workers define skilled migrants by education level without distinguishing whether they acquired their education in the home or the host country this article uses immigrants age of entry as a proxy for where they acquired their education data on age of entry are available from a subset of receiving countries that together represent 77 percent of total skilled immigration to countries of the oecd organization for economic co operation and development using these data and a simple gravity model to estimate the age of entry structure of the remaining 23 percent alternative brain drain measures are proposed that exclude immigrants who arrived before ages 12 18 and 22

assessing interactions among education social insurance and labor market policies in morocco this paper develops a general equilibrium model to assess the impact that integrated reforms of macroeconomic education and social protection policies can have on employment the model presents three innovations first it formalizes the production of skills in the economy by following sex age cohorts through the various levels of the education and training systems given dropout and repetition rates second it incorporates a module that projects social insurance expenditures as a function of the demographic structure of the country and the rules of the pension system finally it develops a very detailed description of the labor market where informality reflects strategic decisions by workers and not necessarily exclusion the model is applied to morocco the results of various simulations illustrate the importance of coordinating macro education and social protection policies in order to achieve meaningful effects on employment levels in particular the author show that isolated interventions to improve the internal efficiency of the education system can aggravate the unemployment problem that subsidies to investments are more efficient in sectors intensive in skilled labor and that not controlling the growth of pension expenditures and the tax wedge can depress employment in the formal sector

finding a maximum skewness portfolio a general solution to three moments portfolio choice considering the three first moments and allowing short sales the efficient portfolios set for n risky assets and a riskless one is found supposing that agents like odd moments and dislike even ones analytical formulas for the solution surface are obtained and important geometric properties provide insights on its shape in the three dimensional space defined by the moments a special duality result is needed and proved the methodology is general comprising situations in which for instance the investor trades a negative skewness for a higher expected return computation of the optimum portfolio weights is feasible in most cases

cyclical quality adjustment in the labor market 1 introductionthe u s unemployment rate fell to very low levels during the 1990s even more impressively the unemployment rate for minorities and less educated individuals fell disproportionately convergence of relative unemployment rates in expansions and divergence in recessions has been a feature of the u s economy over the last 30 years there are many possible reasons for this feature for example if the costs of hiring and firing less skilled labor are low one would expect these individuals to have very procyclical employment in this paper i explore an alternative model when there is an excess supply of labor high skilled people take jobs that would normally be occupied by less skilled people in expansions the process reverses with less skilled workers getting access to jobs that they would normally not attain i refer to this process as cyclical quality adjustment reder 1955 p 834 was one of the first to discuss how hiring standards adjust to business cycle conditions quality variations in labor markets arise through upgrading and downgrading of members of the labor force relative to the jobs they are to fill when applicants become scarce employers tend to lower the minimum standards upon which they insist as a condition for hiring a worker to fill a particular job and vice versa when applicants become plentiful since then many papers have developed this idea theoretically and many economic commentators appear to share this view of the labor market for example the economic report of the president states that a strong labor market is particularly important to less advantaged groups in the labor market such as workers with less education younger workers racial and ethnic minorities and immigrants when employers find it hard to fill vacancies they are more willing to hire and train workers whom they might pass over when they have fewer openings and an abundance of applicants council of economic advisors 1999 p 103 likewise the expansion during the 1990s spawned many newspaper articles about the improvement in the types of jobs available to less skilled applicants however there is little systematic empirical work about changes in job assignment in the united states over the business cycle the empirical work in this paper seeks to redress this situation cyclical assignment changes are important for many reasons as mentioned earlier job upgrading is a potential explanation for the greater cyclical variation of employment experienced by less skilled workers it is well known that the unemployment rates of less skilled individuals and minorities are more countercyclical relative to more skilled individuals clark and summers 1981 kydland 1984 keane and prasad 1993 hoynes 1999 the standard explanation for this effect is that low ability workers are more likely to be laid off in downturns because training and hiring costs are lower for these workers no commensurate attention has been paid to the issue of how the decision of who to hire changes over the business cycle however assignment models present a natural explanation for the greater procyclicality of employment of the less skilled both the adjustment cost hypothesis and the upgrading hypothesis imply that less skilled workers will have more procyclical employment empirically they are distinguishable because the upgrading explanation implies that jobs obtained by comparable workers should vary systematically over the cycle the adjustment cost hypothesis relates to the composition of those whose jobs are terminated second these mechanisms suggest a reason why wages are particularly procyclical for job changers recent studies using panel data have indicated that the wages of job starters are much more procyclical than the wages of workers who do not change jobs researchers have suggested various explanations for this result beaudry and dinardo 1991 and macleod and malcomson 1993 present contracting models in which the wages of job starters depend on the state of the labor market when they join the firm

a note on short term intersectoral factor immobility abstract the dynamic trade literature has identified two important aspects of the adjustment process to real shocks contributed to short term intersectoral factor immobilities real income rises over time as the production factors reallocate while the presence of nontradeable goods leads to a dynamic relative price effect while these effects are usually studied separately in the literature this paper presents a simple multi period model with optimizing agents in which both effects operate simultaneously as an illustration of the model the current account response to a favorable endowment shock is studied the two effects have an opposite impact on the direction of the current account response the relationship between model parameters and the response to the shock is studied

the distribution of talent and the pattern and consequences of international trade i study the interaction between imperfect labor contracts and international trade in a setting in which workers have private information about their own abilities when an individual s contribution to firm output can be measured accurately in some activities but not in others the most able workers select occupations in which their pay most closely reflects their own performance in a world economy with two otherwise similar countries that have different distributions of talent the country with the more heterogeneous labor force exports the good that is produced by the most talented individuals in this country trade exacerbates the polarization of the labor force and often worsens the distribution of income

mixed risk aversion abstract we analyze the class of increasing utility functions exhibiting all derivatives of alternating sign this property that we call mixed risk aversion is satisfied by the utility functions most commonly used in financial economics the utility functions displaying mixed risk aversion can be expressed as mixtures of exponential functions we characterize stochastic dominance and we find conditions for both mutual aggravation and mutual amelioration of risks when agents are mixed risk averse finally the analysis of the distribution function describing a mixed utility allows one to characterize the behaviour of its indexes of risk aversion and to discuss its implications for portfolio selection journal of economic literature classification numbers d81 g11

dynamic models for fixed income portfolio management under uncertainty abstract we develop multi period dynamic models for fixed income portfolio management under uncertainty using multi stage stochastic programming with recourse the models integrate the prescriptive stochastic programs with descriptive monte carlo simulation models of the term structure of interest rates extensive validation experiments are carried out to establish the effectiveness of the models in hedging against uncertainty and to assess their performance vis a vis single period models an application to tracking the salomon brothers mortgage index is reported with very encouraging results results that establish the efficacy of the models in hedging against out of sample scenarios are also reported for an application from money management the multi period models outperform classical models based on portfolio immunization and single period models

how to measure labour market effects of immigration a review abstract this paper surveys available empirical evidence on labour market effects of immigration many different approaches have been used already to try to find out whether immigration hurts the labour market opportunities of natives no doubt new approaches will follow in the future as globalization will keep the migration issue on the agenda this literature review discusses the different approaches concentrating on both the methodology and the results at the end it tries to summarize available evidence

income distribution and macroeconomics this paper analyzes the role of wealth distribution in macroeconomics through investment in human capital it is shown that in the presence of credit markets imperfections and indivisibilities in investment in human capital the initial distribution of wealth affects aggregate output and investment both in the short and in the long run as there are multiple steady states this paper therefore provides an additional explanation for the persistent differences in per capita output across countries furthermore the paper shows that cross country differences in macroeconomic adjustment to aggregate shocks can be attributed among other factors to differences in wealth and income distribution across countries

residential investment and the current account abstract residential investment is an important driving force in the current account this paper first builds the model to show that residential investment for the empirically relevant case where demand for housing services has nonzero income elasticity is fundamentally different from nonresidential investment owing to this income effect the dynamics of housing are subject to the additional integral constraint as well as the standard stock adjustment and euler equations the model is used to examine the effects of changes in government purchases on the tradeable good housing subsidies and productivity shocks on the current account

putting risk in its proper place this paper examines preferences toward particular classes of lottery pairs we show how such concepts as prudence and temperance can be fully characterized by a preference relation over these lotteries if preferences are defined in an expected utility framework with differentiable utility the direction of preference for a particular class of lottery pairs is equivalent to signing the nth derivative of the utility function what makes our characterization appealing is its simplicity which seems particularly amenable to experimentation

toward an understanding of economic growth in africa a reinterpretation of the lewis model summary we develop a model economy that has many of the features of lewis 1954 but that also includes an in between sector as described by lewis 1979 our model underscores the importance of the following determinants of structural change i productivity growth in the agricultural sector ii productivity growth in the nonagricultural sector and iii the terms of trade public investment enhances productivity growth in all sectors but when it is financed by foreign inflows it also causes a real exchange rate appreciation leading to a contraction in the open modern sector these results provide a partial explanation for recent patterns of growth in rwanda and elsewhere in africa where the nontradables or what we call the in between sector has expanded more rapidly than the tradable sector our results also highlight the dilemma faced by poor countries in dire need of public investment with a very limited tax base

vintage human capital growth and the diffusion of new technology we develop a model of vintage human capital in which each technology requires vintage specific skills we examine the properties of a stationary equilibrium for our economy the stationary equilibrium is characterized by an endogenous distribution of skilled workers across vintages the distribution is shown to be single peaked under general conditions there is a lag between the appearance of a technology and its peak usage a phenomenon known as diffusion an increase in the rate of exogenous technological change shifts the distribution of human capital to more recent vintages thereby increasing the diffusion rate

migration and labour markets in oecd countries a panel cointegration approach this article examines the interaction between immigration and the host labour market of 14 organization for economic co operation and development oecd countries using nonstationary panel data methodology we estimate a trivariate vector error correction model vecm and derive causality tests to simultaneously assess the long and short term macroeconomic impact of newcomers on wages and unemployment levels in the host country the results suggest that an increase of migrants is likely to increase wages in the destination countries in the short run but to increase them in the long run there is no evidence of adverse effects on unemployment due to immigration in short and long term except for anglo saxon countries in the short term our findings also show that immigration is conditioned by levels of unemployment and wages especially in anglo saxon countries

the performance of us equity mutual funds the paper examines the performance of us no load equity mutual funds fund performance is derived using stochastic frontier analysis for a flexible functional form this analysis allows us to derive parametric estimates of efficiency scores for each fund in our sample for the first time in the literature our results indicate that us no load equity funds display varying levels of efficiency over time but also depending on size and on investment style robustness analysis reaffirm the efficiency scores remain consistent across different selections of inputs and outputs as well as the underlying distribution of the return having estimated each fund s efficiency in the sample we unveil their underlying dynamics also with respect to risk and operational characteristics such as flows assets and morningstar star ratings panel var estimations reveal that the response of funds efficiency to a shock in risk is positive and substantial some evidence of reverse causality is also observed finally we extend our analysis to investigate the relationship between funds performance and key covariates across subgroups defined by size

mexican immigrant employment outcomes over the business cycle the united states is beginning to emerge from the deepest downturn the country has experienced since the great depression as of october 2009 the number of unemployed persons had risen by 8 2 million since the great recession began in december 2007 all demographic groups have experienced job losses but some groups have been more adversely affected than others repeating the pattern of most previous downturns the recession s impact has been worst for low education and minority workers one group that has been particularly hard hit is mexican immigrants data from the current population survey indicate that between the first quarter of 2007 and the second quarter of 2009 the unemployment rate among mexican immigrants rose from 4 2 percent to 11 3 percent and their employment rate dropped by 5 percentage points in contrast during that period the unemployment rate among non hispanic white natives rose from 3 7 percent to 7 8 percent and their employment rate fell by 2 6 percentage points mexican immigrants tend to be particularly vulnerable to economic downturns because of their relatively low skill levels they make up one fourth of all workers who do not have a high school diploma or equivalent and over one half of workers who have completed at most eighth grade when the economy slows employers look to shed their least productive employees first employers tend to invest less in training low skilled workers and therefore have less

explaining diversity symmetry breaking in complementarity games strategic complementarity games have found applications in many fields including macroeconomics development and labor economics they provide a useful framework within which to address questions like what generates the disparity across regions and countries why are there booms and recessions and what causes gender and race discrimination in the labor market in short they help us think about the diversity and variations across space time and groups the literature on complementarity games has emphasized coordination failures as the key notion to understand these questions this paper argues that such emphasis is misplaced the key to understand the diversity is symmetrybreaking the notion of coordination failures is not only irrelevant but also misleading when thinking about the diversity

self defeating regional concentration most policy debates on regional policies implicitly assume that there is too much concentration in our two region model of migration desirable concentration fails to occur under some conditions and undesirable concentration occurs in others in the latter case even though the individuals collectively prefer to be distributed evenly across the two regions they end up concentrating into one region in their pursuit of a better life hence the freedom to move can be self defeating we characterize the conditions for such self defeating concentration to occur the coordination failures between the entry decision of service firms and the migration decision of individuals are caused by the incompleteness of markets due to the endogeneity of the range of services available which deprive the agents of the opportunity to signal demand and supply for potential services the argument does not rely on price distortions the nonconvexities implied by increasing returns and nontradedness congestion externalities nor myopia in migration decisions

the dynamics of the wealth distribution and the interest rate with credit rationing are uniquely determined and wealth dispersion among individuals or firms is irrelevant introducing credit rationing into the solow model modifies these conclusions multiple stationary interest rates and wealth distributions can exist because higher initial rates can be self reinforcing through higher credit rationing and lower capital accumulation the wealth accumulation process is ergodic in every steady state but wealth mobility is lower with higher steady state interest rates aggregate output is higher in steady states with lower interest rates because credit is better allocated short run interest rate or distribution shocks can be self sustaining and can have long run effects on output through the induced dynamics of the wealth distribution and credit rationing

geometric representation of the mean variance skewness portfolio frontier based upon the shortage function the literature suggests that investors prefer portfolios based on mean variance and skewness rather than portfolios based on mean variance mv criteria solely furthermore a small variety of methods have been proposed to determine meanvariance skewness mvs optimal portfolios recently the shortage function has been introduced as a measure of e ciency allowing to characterize mvs optimal portfolios using non parametric mathematical programming tools while tracing the mv portfolio frontier has become trivial the geometric representation of the mvs frontier is an open challenge a hitherto unnoticed advantage of the shortage function is that it allows to geometrically represent the mvs portfolio frontier the purpose of this contribution is to systematically develop geometric representations of the mvs portfolio frontier using the shortage function and related approaches