learning about a new technology pineapple in ghana this paper investigates the role of social learning in the diffusion of a new agri cultural technology in ghana we use unique data on farmers communication patterns to define each individual s information neighborhood conditional on many potentially confounding variables we find evidence that farmers adjust their inputs to align with those of their information neighbors who were surpris ingly successful in previous periods the relationship of these input adjustments to experience further indicates the presence of social learning in addition applying the same method to input choices for another crop of known technol ogy correctly indicates an absence of social learning effects jel d83 013 033 q16

if we knew ability how would we tax individuals abstract the suggestion to tax people on earnings capacity instead of earnings has been around for a long time and is attractive in terms of economic efficiency in this paper we reflect on the feasibility of such a system and give an exploratory empirical implementation we apply the leyden welfare function of income a survey based measure of an individual s welfare associated with income to derive implications for ability taxation under the assumption that iq and schooling reflect earnings capacity we derive the tax functions using different criteria to distribute the utility loss due to taxation

family and community networks in mexico u s migration a household s decision to send migrants is based on infornation it has on the entry costs expected returns and risks of migration information and assistance flow from both family migrant networks and community migrant networks using data from a national survey of rural mexican households we show the importance of networks in both the decision to migrate and the level of migration we find that community and family networks are substitutes in assisting migration suggesting that once migration is well established in a community family networks become less important in addition the development of strong community networks erases the role of household characteristics in migration allowing those initially least favored to also participate in migration finally we show that network density at points of destination in the united states strongly affects where individuals choose to migrate

optimal capital income taxation with incomplete markets borrowing constraints and constant discounting for a wide class of infinitely lived agent models chamley has shown that the optimal capital income tax rate is zero in the long run lucas has argued that for the u s economy there is a significant welfare gain from switching to this policy this paper shows that for the bewley class of models with incomplete insurance markets and borrowing constraints the optimal tax rate on capital income is positive even in the long run therefore cutting the capital income tax to zero may well lead to welfare losses

positive and normative judgments implicit in u s tax policy and the costs of unequal growth and recessions calculating the welfare implications of changes to economic policy or shocks requires economists to decide on a normative criterion one approach is to elicit the relevant moral criteria from real world policy choices converting a normative decision into a positive inference as in the recent surge of inverse optimum research we find that capitalizing on the potential of this approach is not as straightforward as we might hope we perform the inverse optimum inference on u s tax policy from 1979 through 2010 and argue that the results either undermine the normative relevance of the approach or challenge conventional assumptions upon which economists routinely rely when performing welfare evaluations

commitment and fairness in a dynamic regulatory relationship this paper considers a multiperiod model of a regulated firm that has stationary private information which may be revealed through performance if it cannot make commitments to future policies the regulator has an incentive to exploit any information the firm reveals and laffont and tirole show that there is no regulatory policy that is separating over any closed interval a fairness arrangement is proposed in which the firm agrees not to quit if in future periods the regulator allows it to earn a nonnegative profit given the type it revealed in earlier periods the properties of such arrangements are studied and an example is presented in which both the firm and the regulator prefer a fairness arrangement to a policy feasible without commitment

the undesirability of randomized income taxation under decreasing risk aversion abstract for the standard specification of the utilitarian optimal income tax problem with hidden characteristics the paper shows that randomized tax schemes are undesirable if preferences exhibit a property of weakly decreasing risk aversion according to the multidimensional risk aversion concept of hellwig hellwig m f 2004 risk aversion in the small and the large with multidimensional outcomes max planck institute for research on collective goods bonn preprint 2004 6 http www mpp rdg mpg de pdf dat 2005 23online pdf this property of decreasing risk aversion also implies that the optimal income tax schedule is unique and depends continuously on the data of the problem

a contribution to the theory of optimal utilitarian income taxation abstract the paper provides a new formulation of the mirrlees seade theorem on the positivity of the optimal marginal income tax under weaker assumptions and in a more general model the formulation of the theorem is independent of whether the model involves finitely many types or a continuous type distribution the formal argument makes the underlying logic transparent relating the mathematics to the economics and showing precisely how each assumption enters the analysis

computing multi period information constrained optima this paper presents a detailed theoretical derivation and justification for methods used to compute solutions to a multi period including infinite period continuum agent unobservedeffort economy actual solutions are displayed illustrating cross sectional variability in consumption and labour effort in the population at a point in time and variability for a typical individual over time the optimal tradeoff between insurance and incentives is explored and the issue of excess variability is addressed by consideration of the analogue full information economy and various restricted contracting regimes

how important are idiosyncratic shocks evidence from labor supply the notion that individuals face idiosyncratic labor market uncertainty is a common one government programs such as unemployment insurance and social security are motivated by such an idea economic theory ranging from labor supply to savings behavior to asset pricing often presupposes that such risks are important a number of papers however have questioned this orthodoxy sumru altug and robert a miller 1990 for instance are unable to reject a set of factor structure restrictions implied by complete markets john h cochrane 1991 and barbara j mace 1991 find evidence of consumption insurance although not against all types of risks robert m townsend 1994 documents evidence of risk sharing in indian villages michael p keane and kenneth i wolpin 1997 argue that 90 percent of the labor market uncertainty faced by a group of males is resolved by age 16 other studies have suggested the opposite papers by joseph g altonji et al 1991 orazio attanasio and steven j davis 1996 and attanasio and guglielmo weber 1992 as well as some evidence in cochrane 1991 and mace 1991 suggest that risk sharing is far from complete in particular for low frequency shocks angus deaton and christina paxson 1994 show that inequality in labor earnings total income and consumption increases with age they suggest that this is difficult to reconcile with standard models of complete consumption insurance in storesletten et al 2000 we ask similar questions using a general equilibrium life cycle model we conclude that increasing inequality with age consumption inequality in particular is difficult to explain in the absence of uninsured idiosyncratic shocks received throughout the working years we argue that between 40 percent and 50 percent of an individual s lifetime uncertainty remains unresolved prior to entering the workforce this paper further examines the implications of increasing inequality with age we begin by asking if a very different model one which features full risk sharing can account for the data the idea which deaton and paxson 1994 attribute to steven davis is that increasing income and consumption inequality can arise in a perfect insurance setting if i dispersion in labor productivity increases with age and ii preferences are nonseparable between leisure and consumption if this is true an efficient allocation may feature increasing consumption dispersion because higher productivity workers will supply relatively more labor and be compensated with more consumption we develop a specific model and find that for plausible parameter values this is exactly what happens what also happens however is that such an allocation features increasing inequality in hours worked using data from the panel study on income dynamics psid we show that inequality in hours worked is roughly constant across age this casts doubt on the full risksharing model and strengthens the argument in favor of uninsurable idiosyncratic risk the remainder of our paper provides a more general discussion of the evidence on inequality and age and how this suggests an important role for idiosyncratic labor market shocks

analysis of environmental efficiency variation in this article we develop and implement a methodology for analyzing the sources of variation in environmental efficiency across producers we formulate a two stage model in the first stage we use stochastic frontier analysis to estimate both technical and environmental efficiency in the second stage we again use stochastic frontier analysis to regress estimated environmental efficiency scores against a variety of technology physical environment and management variables in this stage we estimate the impact of each explanatory variable on environmental efficiency and we derive conditional estimates of environmental efficiency from the one sided error component we illustrate our methodology with an empirical application to a panel of dutch dairy farms we find evidence of relatively low levels of environmental efficiency and we find that environmental efficiency can be improved through a number of policy options including the provision of farmers with more insight into the nutrient balance of their farms

risk sharing networks and insurance against illness most risk sharing tests on developing country data are conducted at the level of the village generally the full risk sharing hypothesis is rejected this paper uses detailed data on all insurance networks within a village in tanzania networks are not clustered but largely overlapping we test whether full risk sharing occurs within these networks while village level full insurance cannot be rejected for food consumption we find evidence consistent with at least partial insurance of non food consumption via networks

on the optimality of optimal income taxation abstract the mirrleesian model of income taxation restricts attention to simple allocation mechanism with no strategic interdependence i e the optimal labor supply of any one individual does not depend on the labor supply of others it has been argued by piketty 2009 12 that this restriction is substantial because more sophisticated mechanisms can reach first best allocations that are out of reach with simple mechanisms in this paper we assess the validity of piketty s critique in an independent private values model as a main result we show that the optimal sophisticated mechanism is a simple mechanism or equivalently a mirrleesian income tax system

the formation of risk sharing networks this paper examines the formation of risk sharing networks in the rural philippines we find that geographic proximity possibly correlated with kinship is a major determinant of mutual insurance links among villagers age and wealth differences also play an important role in contrast income correlation and differences in occupation are not determinants of network links reported network links have a strong effect on subsequent gifts and loans gifts between network partners are found to respond to shocks and to differences in health status from this we conclude that intra village mutual insurance links are largely determined by social and geographical proximity and are only weakly the result of purposeful diversification of income risk the paper also makes a methodological contribution to the estimation of dyadic models

meeting strangers and friends of friends how random are social networks we present a dynamic model of network formation where nodes find other nodes with whom to form links in two ways some are found uniformly at random while others are found by searching locally through the current structure of the network e g meeting friends of friends this combination of meeting processes results in a spectrum of features exhibited by large social networks including the presence of more high and low degree nodes than when links are formed independently at random having low distances between nodes in the network and having high clustering of links on a local level we fit the model to data from six networks and impute the relative ratio of random to network based meetings in link formation which turns out to vary dramatically across applications we show that as the random network based meeting ratio varies the resulting degree distributions can be ordered in the sense of stochastic dominance which allows us to infer how the formation process affects average utility in the network

peer effects and social networks in education this paper studies whether structural properties of friendship networks affect individual outcomes in education we first develop a model that shows that at the nash equilibrium the outcome of each individual embedded in a network is proportional to her katz bonacich centrality measure this measure takes into account both direct and indirect friends of each individual but puts less weight to her distant friends we then bring the model to the data by using a very detailed dataset of adolescent friendship networks we show that after controlling for observable individual characteristics and unobservable network specific factors the individual s position in a network as measured by her katz bonacich centrality is a key determinant of her level of activity a standard deviation increase in the katz bonacich centrality increases the pupil school performance by more than 7 percent of one standard deviation

optimal multiperiod contracts and the gain from enduring relationships under private information informational asymmetries can play a key role in explaining the existence and nature of multiperiod contracts in an illustrative risk sharing model even relatively short two period contracts can be mutually beneficial if there is private information though one period contracts suffice otherwise further contracts which are pareto optimal relative to the environment and the information structure are defined and partially characterized an example illustrates how otherwise inefficient intertemporal tie ins can be used optimally to mitigate incentive problems the obvious borrowing lending schemes are not private information pareto optimal in these period by period actions are not sufficiently constrained discounting affects the form of the optimal contract but none of these qualitative conclusions

the game form approach to redistribution this paper reviews the game form approach to redistributive policies this approach provides a justiucation for studying tax systems as good institutional arrangements for reallocating resources in a heterogeneous society after situating the problem of asymmetric information for public policy the paper provides a short overview of the main concepts and results in implementation theory next these tools are used to inquire about the possibility to decentralise the reallocation of resources in a production economy with the help of tax transfer systems finally the paper deals with some recent extensions of the theory a simple example is used throughout to illustrate the different results

redistributive taxation in a simple perfect foresight model abstract we investigate the redistributive potential of capital taxation in an intertemporal maximizing model of capital formation first even unanticipated redistributive capital taxation is severely limited in its effectiveness since it depresses wages second under any convergent redistributive tax policy which maximizes a paretian social objective the capital income tax will converge to zero independent of the factor supply elasticities these results are independent of workers holdings of capital

the old boy and girl network social network formation on university campuses this paper documents the structure and composition of social networks on university campuses and investigates the processes that lead to their formation using administrative data and information from facebook com we document the factors that are the strongest predictors of whether two students are friends race is strongly related to social ties even after controlling for a variety of measures of socioeconomic background ability and college activities we develop a model of the formation of social networks that decomposes the formation of social links into effects based upon the exogenous school environment and effects of endogenous choice arising from preferences for certain characteristics in one s friends we use student level data from an actual social network to calibrate the model we simulate the social network under alternative university policies aimed at reducing social segmentation we find that changes in the school environment that affect the likelihood that two students interact have only a limited potential to reduce the racial segmentation of the social network

monopoly with incomplete information recent theoretical research on principal agent relationships has emphasized incentive problems that arise when the parties involved are constrained by either asymmetric information or their inability to monitor each other s actions here we concentrate on the former constraint and consider the case of a single principal the monopolist the main contribution is to show that under a separability assumption strong conclusions can be drawn about the nature of optimal incentive schemes although the primary focus is on optimal quantity discounts in a monopolized market the results also shed light on related topics such as optimal income taxation and commodity bundling

the effects of moral hazard on asset prices when financial markets are complete abstract this paper discusses the implications for prices and quantities of an alternative trading arrangement in kahn s 1990 economic environment with moral hazard unlike kahn s model of asset trade my model does not impose any unmotivated restrictions on short sales instead it features complete markets and publicly observable asset transactions like kahn s model my model implies that allocations are constrained pareto optimal however the implications of my model for asset prices are considerably different in particular when all agents have log utility asset prices satisfy an aggregation theorem also unlike kahn s model the model in this paper does worse than the standard representative agent model in terms of explaining the equity premium

coordinating development can income based incentive schemes eliminate pareto inferior equilibria individuals inability to coordinate investment may significantly constrain economic development in this paper we study a simple investment game characterized by multiple equilibria and ask whether an income based incentive scheme can uniquely implement the high investment outcome a general property of this game is the presence of a crossover investment point at which an individual s incomes from investment and noninvestment are equal we show that arbitrarily small errors in the government s knowledge of this crossover point can prevent unique implementation of the high investment outcome we conclude that informational requirements are likely to severely limit a government s ability to use income based incentive schemes as a coordination device

network effects and the dynamics of migration and inequality theory and evidence from mexico international migration is costly and initially only the middle class of the wealth distribution may have both the means and incentives to migrate which can increase inequality in the sending community however the migration networks formed lower the costs for future migrants which can in turn lower inequality this paper shows both theoretically and empirically that wealth has a nonlinear effect on migration and then examines the empirical evidence for an inverse u shaped relationship between emigration and inequality in rural sending communities in mexico after instrumenting we find that the overall impact of migration is to reduce inequality across communities with relatively high levels of past migration we also find some suggestive evidence for an inverse u shaped relationship among communities with a wider range of migration experiences

economics an emerging small world we study the evolution of social distance among economists over the period 1970 2000 while the number of economists has more than doubled the distance between them which was already small has declined significantly the key to understanding the short average distances is the observation that economics is spanned by a collection of interlinked stars a star is an economist who writes with many other economists most of whom have few coauthors and generally do not write with each other

growth and risk sharing with private information abstract we examine the impact of incomplete risk sharing on growth and welfare the source of market incompleteness in our economy is private information a household s idiosyncratic productivity shock is not observable by others risk sharing between households occurs through long term contracts with intermediaries we find that incomplete risk sharing tends to reduce the rate of growth relative to the complete risk sharing benchmark numerical examples indicate that the welfare cost and the growth effect of private information are small

public benefits private benefits and policy mechanism choice for land use change for environmental benefits the choice of policy mechanisms for encouraging environmentally beneficial land use change should depend on the relative levels of private or internal net benefits and public or external net benefits a map of recommended policy mechanisms is developed depending on the relative levels of these variables positive incentives negative incentives and extension need to be targeted carefully to appropriate projects where private net benefits are closer to zero and or public net benefits are more extremely positive or negative technology development is suggested where private net costs outweigh public net benefits no action is recommended for many potential projects

implementation of first best allocations via generalized tax schedules abstract the classical problem of optimal taxation introduced by j mirrlees rev econ stud 38 1971 175 208 is addressed and it is argued that by using generalized tax schedules i e schedules which depend not only on individual income but also on the whole profile of incomes announced by the society a planner can implement any pareto optimum which stands in great contrast with the set of second best pareto optima attainable via classical tax schedules the mechanism relies crucially on the fixed probability distribution of characteristics and on a finite number of agents journal of economic literature classification numbers d78 d82 h21

incentives and aggregate shocks this paper presents an incentive based theory of the dynamics of the distribution of consumption in the presence of aggregate shocks the paper builds on the models concerning the distribution of income or consumption and incentive problems of green 1987 thomas and worrall 1991 phelan and townsend 1991 and atkeson and lucas 1992 by incorporating aggregate production shocks the model allows an examination of the interactions between individual and aggregate consumption series given incomplete insurance further the methodology outlined allows the incorporation of incentive considerations to macroeconomic environments similar to rogerson 1988 and hansen 1985

efficiency and equality in a simple model of efficient unemployment insurance abstract this paper describes the efficient allocation of consumption and work effort in an economy in which workers face idiosyncratic employment risk and considerations of moral hazard prevent full insurance we impose a lower bound on the expected discounted utility that can be assigned to any agent from any date onward and show with this feature added that the efficient unemployment insurance scheme induces an invariant cross sectional distribution of individual entitlements to utility the paper thus provides a simple prototype model suited to the study of the normative question what is the trade off between equality and efficiency in resource allocation journal of economic literature classification numbers d31 d63 d82 j65

direct versus indirect taxation the design of the tax structure revisited this article studies the optimal direct indirect tax mix problem when individuals differ in several unobservable characteristics productivity and endowments it presents general expressions for the optimal commodity tax rates and proves that contrary to atkinson and stiglitz s 1976 result differential commodity taxation remains a useful instrument of tax policy even if preferences are separable between labor and produced goods when cross substitution effects are zero the expressions resemble traditional many households ramsey rules in a cobb douglas illustration where endowments differ only in good 1 interpreted as wealth the tax on good 2 provides an indirect way to tax the unobservable wealth

analysis of environmental efficiency variations a nutrient balance approach recent literature has argued that environmental efficiency ee which is built on the materials balance mb principle is more suitable than other ee measures in situations where the law of mass conversation regulates production processes in addition the mb based ee method is particularly useful in analysing possible trade offs between cost and environmental performance identifying determinants of mb based ee can provide useful information to decision makers but there are very few empirical investigations into this issue this article proposes the use of data envelopment analysis and stochastic frontier analysis techniques to analyse variation in mb based ee specifically the article develops a stochastic nutrient frontier and nutrient inefficiency model to analyse determinants of mb based ee the empirical study applies both techniques to investigate mb based ee of 96 rice farms in south korea the size of land fertiliser consumption intensity cost allocative efficiency and the share of owned land out of total land are found to be correlated with mb based ee the results confirm the presence of a trade off between mb based ee and cost allocative efficiency and this finding favouring policy interventions to help farms simultaneously achieve cost efficiency and mp based ee

payroll tax financed social insurance with variable retirement the optimal relationship between retirement benefits and retirement age is derived the model assumes ex ante identical workers zero one labor supply no private savings wages and payroll taxes constant over life random onset of an inability to work and the impossibility of distinguishing those unable to work from those choosing retirement this formulation is meant to capture some issues for retirement programs where governments commonly do not measure disability e g ages 65 70 with intertemporally additive preferences optimal benefits rise with the age of retirement but more slowly than would be actuarially fair a nonadditive example is also considered

voting over selfishly optimal nonlinear income tax schedules abstract majority voting over selfishly optimal nonlinear income tax schedules proposed by a continuum of individuals who have quasilinear in consumption preferences is considered roell 2012 has shown that individual preferences over these schedules are single peaked in this article a complete characterization of selfishly optimal schedules is provided each selfishly optimal schedule has a bunching region in a neighborhood of the proposer s skill type coincides with the maxi max schedule below this region and coincides with the maxi min schedule above it using techniques introduced by vincent and mason 1967 the bunching region is identified by solving an unconstrained optimization problem information about the optimal schedules is used to provide a relatively simple proof of single peakedness the condorcet winning tax schedule features marginal tax rates that are negative resp positive on the maxi max resp maxi min part of the schedule except at the endpoints of the skill distribution where they are zero

economic inefficiency and environmental impact an application to aquaculture production abstract in industries characterized by frequent innovation and high productivity growth substantial variation in produced quantity and input use may occur leading to increased costs an effect that has received little attention is that inefficiency can exacerbate environmental impacts this effect is particularly important if environmentally damaging inputs are overused in addition to increasing firms costs such inefficiency can also increase the environmental impact of the firm s activity this makes the degree of inefficiency in an industry an issue for environmental regulators in this paper we estimate technical and allocative efficiency for a sample of norwegian salmon farmers our results show that both technical and allocative inefficiency on average are significant in explaining the level and variation in farm costs and that the main environmental impact due to inefficiency from the norwegian salmon aquaculture industry has its origin in technical inefficiency

optimal indirect and capital taxation we consider an environment in which agents skills are private information and follow arbitrary stochastic processes we prove that it is typically pareto optimal for an individual s marginal benefit of investing in capital to exceed his marginal cost of doing so this wedge is consistent with a positive tax on capital income we also prove that it is pareto optimal for the marginal rate of substitution between any two consumption goods to equal the marginal rate of transformation this lack of a wedge is consistent with uniform taxation of consumption goods within a period

pareto optima and competitive equilibria with adverse selection and moral hazard this paper explores the extent to which standard general equilibrium analysis of pareto optima and of competitive equilibria can be applied to environments with moral hazard and adverse selection problems allowing for lotteries contracts with random components we first establish that an adverse selection insurance economy a moral hazard insurance economy a signaling economy and a private information labor market economy are all special cases of a simple general structure we then show that techniques for characterizing pareto optimal contracts as solutions to concave programming problems are useful and nice and appear to be broadly applicable allowing for lotteries we show how to characterize the optimal allocations for the adverse selection insurance and labor market economies we then show that standard existence and optimality theorems for competitive equilibria apply in the linear space containing lotteries if agents with characteristics which are distinct and privately observed at the time of initial trading enter the economy wide resource constraints in a homogeneous way other kinds of diversity are not critical for economies with moral hazard which satisfy the homogeneity condition competitive contract markets single out a subset of the optima and thus can be consistent with apparent unemployment and with a random allocation of labor supplied though all households are averse to risk the adverse selection insurance and signaling economies however do not satisfy the homogeneity condition and are difficult to decentralize efficiently with a price system

a note on optimal income taxation public goods provision and robust mechanism design abstract this paper extends the model of optimal income taxation due to mirrlees mirrlees j 1971 an exploration in the theory of optimum income taxation review of economic studies 38 175 208 and includes private information on public goods preferences a mechanism design approach is used to establish the following result if policies are required to be robustly implementable in the sense of bergemann and morris bergemann d morris s 2005 robust mechanism design econometrica 73 1771 1813 then the optimality conditions in the extended model with uncertainty about tax and expenditure policies are the same as in the standard model of optimal income taxation the paper provides a foundation for a widely used assumption in public finance namely that individuals optimize their behavior subject to a predetermined and commonly known tax system

information and incentives the economics of carrots and sticks prize lecture to the memory of alfred nobel december 9 1996 this abstract was borrowed from another version of this item

progressive estate taxation we present a model with altruistic parents and heterogeneous productivity we derive two key properties for optimal estate taxation first the estate tax should be progressive so that parents leaving a higher bequest face a lower net return on bequests second marginal estate taxes should be negative so that all parents face a marginal subsidy on bequests both properties can be implemented with a simple nonlinear tax on bequests levied separately from the income tax these results apply to other intergenerational transfers such as educational investments and are robust to endogenous fertility choices both estate or inheritance taxes can implement the optimal allocation but we show that the inheritance tax has some advantages finally when we impose an ad hoc constraint requiring marginal estate taxes to be nonnegative the optimum features a zero tax up to an exemption level and a progressive tax thereafter

when green isn t mean economic theory and the heuristics of the impact of environmental regulations on competitiveness and opportunity cost abstract the conventional neoclassical economic wisdom argues that the opportunity costs of environmental regulations are high with negative implications for costs and profits and by implication for growth and per capita gross domestic product gdp the minority view that environmental controls induce cost offsets that minimise such opportunity costs is marginalised by the conventional wisdom which assumes that economic agents are x efficient in production a behavioral model of the firm is presented in this paper whereby x inefficiency in production prevails even in a world of perfect product market competition that is dominated by rational economic agents in this model environmental regulations affect both the level of x efficiency and the extent of technological change and greener firms can be cost competitive and profitable however private economic agents cannot be expected to adopt green economic policy independent of regulations since in this model there need not be any economic advantage accruing to the affected firms in becoming greener

valuing the environment as input review of applications to mangrove fishery linkages the following paper reviews recent developments in the methodology for valuing the role of wetlands in supporting economic activity the main focus will be on mangroves serving as a breeding ground and nursery habitat in support of coastal and marine fisheries as this particular ecological function of a mangrove system means that it is effectively an unpriced environmental input into fisheries then it is possible to value this contribution through applying the production function approach the first half of the paper overviews the procedure for valuing the environment as an input applied to the case of a wetland supporting a fishery both the static ellis fisher freeman approach and the dynamic approach developed by barbier and strand incorporating the intertemporal bioeconomic fishing problem are reviewed the second half of the paper discusses briefly two recent case studies of mangrove fishery valuation an application in south thailand which is based on the static ellis fisher freeman model and an application in campeche mexico which is based on the dynamic approach 2000 elsevier science b v all rights reserved

on efficient distribution with private information this paper is a study of the dynamics of the efficient distribution of consumption in an exchange economy with many consumers each of whom is subject to private idiosyncratic taste shocks we propose a recursive method for finding feasible allocations that are incentivecompatible and that are pareto optimal within this set the method is applied to several parametric examples we find that in an efficient allocation the degree of inequality continually increases with a diminishing fraction of the population receiving an increasing fraction of the resources we discuss the extent to which these allocations can be decentralized via market arrangements this paper is a study of the dynamics of the efficient distribution of consumption in an exchange economy with private information the economy we study has a constant endowment flow of a single non storable consumption good which is to be allocated each period among a large number of consumers each period these consumers experience unpredictable idiosyncratic privately observed taste shocks affecting their marginal utility of current consumption efficiency dictates that more resources be allocated to those consumers who in any given period have a high marginal utility of current consumption

on the robustness of laissez faire abstract this paper considers a model economy in which agents are privately informed about their type their endowments of various goods and their preferences over these goods while preference orderings over observable choices are allowed to be correlated with an agent s private type we assume that the planner government is both uncertain about the nature of this joint distribution and unable to choose among multiple equilibria of any given social mechanism we model the planner government as having a maxmin objective in the face of this uncertainty our main theorem is as follows once we allow for this kind of uncertainty and assume no wealth effects in preferences the uniquely optimal social contract is laissez faire in which agents trade in unfettered markets with no government intervention of any kind

what s driving mexico u s migration a theoretical empirical and policy analysis using data gathered in 25 mexican communities the authors link individual acts of migration to 41 theoretically defined individual household community and macroeconomic level predictors the indicators vary through time to yield a discrete time event history analysis over the past 25 years probabilities of first repeat and return migration have been linked more to the forces identified by social capital theory and the new economics of migration than to the cost benefit calculations assumed by the neoclassical model the authors find that mexico u s migration stems from three mutually reinforcing processes social capital formation human capital formation and market consolidation

optimal nonlinear income taxation with a finite population abstract in the standard optimal income taxation problem tax payments depend only on each consumer s own actions piketty j econ theory 61 1993 23 41 shows that if one individual s tax schedule depends on others actions and the government knows the exact ability distribution it can implement any undistorted allocation as the unique revelation game outcome if some individuals misreveal their types piketty s mechanism may assign infeasible allocations we require that tax schedules must balance the government budget for every possible vector of revelations when individuals reveal their type by simple announcements all undistorted allocations can be still implemented even with off equilibrium feasibility constraints

a strategic model of social and economic networks we study the stability and efficiency of social and economic networks when self interested individuals can form or sever links first for two stylized models we characterize the stable and efficient networks there does not always exist a stable network that is efficient next we show that this tension persists generally to assure that there exists a stable network that is efficient one is forced to allocate resources to nodes that are not responsible for any of the production we characterize one such allocation rule the equal split rule and another rule that arises naturally from bargaining of the players

the value of environment across efficiency quantiles a conditional regression quantiles analysis of rangelands beef production in north eastern australia in agricultural systems the value of environmental inputs can be measured using the production function approach whereby the marginal contributions of factors are associated with a shadow value under perfect competition and rationality assumptions however empirical studies show that inefficiency in production is common indicating that the rationality assumption is not met furthermore substantial evidence exists to suggest that the contributions of environmental inputs in particular may be differentiated across the efficiency distribution this means that the frontier technology may not be an appropriate reflection of the technology in use by inefficient enterprises this article presents the use of conditional regression quantiles to consider how the value of environmental inputs measured by their contributions to production vary across efficiency quantiles we employed a case study of rangelands beef production in australia to consider how environmental health differentially contributes to production values across efficiency quantiles our approach generates detailed insights into the nature of environmentally sourced technical inefficiency and suggests that conditional quantile regression approaches are ideal for consideration of issues wherein substantial heterogeneity exists limiting the information content of conditional mean based analyses

the effects of social networks on employment and inequality we develop a model where agents obtain information about job opportunities through an explicitly modeled network of social contacts we show that employment is positively correlated across time and agents moreover unemployment exhibits duration dependence the probability of obtaining a job decreases in the length of time that an agent has been unemployed finally we examine inequality between two groups if staying in the labor market is costly and one group starts with a worse employment status then that group s drop out rate will be higher and their employment prospects will be persistently below that of the other group

the environment as a factor of production the authors develop a model of environmental resource use in production with an empirical analysis of how electric power companies consume and bank sulfur dioxide pollution permits the model considers emissions fuels and labor as variable inputs with quasi fixed inputs of permits and capital incorporating information from permit markets allows the authors to distinguish between user costs and asset shadow values their findings indicate that firms are holding stocks of pollution permits for reasons other than short term cost savings the results also reveal substantial substitution possibilities between emissions permits stocks and other factors of production the authors speculate that anticipated secondary markets for carbon offset inventories related to the flexibility mechanisms of the kyoto protocol will have similar effects for greenhouse gas emitting firms

group formation in risk sharing arrangements we study informal insurance within communities explicitly recognizing the possibility that subgroups of individuals may destabilize insurance arrangements among the larger group we therefore consider self enforcing risk sharing agreements that are robust not only to single person deviations but also to potential deviations by subgroups however such deviations must be credible in the sense that the subgroup must pass exactly the same test that we apply to the entire group it must itself employ some self enforcing risk sharing agreement we observe that the stability of subgroups is inimical to the stability of the group as a whole two surprising consequences of this analysis are that stable groups have uniformly bounded size a result in sharp contrast to the individual deviation problem and that the degree of risk sharing in a community is generally non monotonic in the level of uncertainty or need for insurance in the community

efficiency welfare and political competition we study political competition in an environment in which voters have private information about their preferences our framework covers models of income taxation public goods provision or publicly provided private goods politicians are vote share maximizers they can propose any policy that is resource feasible and incentive compatible they can also offer special favors to subsets of the electorate we prove two main results first the unique symmetric equilibrium is such that policies are surplus maximizing and hence first best pareto efficient second there is a surplus maximizing policy that wins a majority against any welfare maximizing policy thus in our model policies that trade off equity and efficiency considerations are politically infeasible jel codes c72 d72 d82 h21 h41 h42

the formation of migrant networks in this paper we provide the first direct evidence on the internal structure of the migrant social network by using a purposely designed survey on sri lankan immigrants living in milan we show that the pattern of within group link formation is heterogeneous across immigrants and differentiated according to the network function i e accommodation credit job finding we find that migrants tend to interact with co nationals who come from nearby localities at origin while the time of arrival has a u shaped effect once the link is formed material support is provided mainly to relatives while early migrant fellows are helpful for job finding abstract from author

intertemporal distortions in the second best we consider a very general class of public nance problems that encompasses ramsey models of optimal taxation as well as economies with limited commitment private information and political economy frictions we identify a su cient condition to rule out permanent intertemporal distortions at the optimum if there exists an admissible allocation that converges to the rst best steady state then all intertemporal distortions are temporary in the second best we analyze a series of applications to illustrate the signi cance of this result

optimal taxation of capital income in general equilibrium with infinite lives this paper analyzes the optimal tax on capital income in general equilibrium models of the second best agents have infinite lives and utility functions which are extensions from the koopmans form the population is heterogeneous the important property of the models is the equality between the social and the private discount rates in the long run i find that the optimal tax rate is zero in the long run for a special case of additively separable utility functions i then determine the tax rates along the dynamic path and conditions that are sufficient for the local stability of the steady state

nonlinear price discrimination with a finite number of consumers and constrained recontracting abstract in the monopoly nonlinear pricing problem with unobservable consumer types we study mechanisms in which the firm makes the set of consumer options conditional on the aggregate reports of consumer types it receives previous mechanisms that exploit knowledge of the true type distribution often have multiple equilibria or use noncredible contracts off the equilibrium path when the monopolist can replace contracts after initial reports subject to the constraint that truthful consumers are not made worse off the outcome is essentially the same as when the monopolist has full information this holds whether or not the monopolist can make offers to consumers who reject all original contract offers when the monopolist must guarantee nonnegative surplus to all truthful consumers in all contingencies the equilibrium outcome has undistorted contracts but lower profits for the monopolist

do conservation auctions crowd out voluntary environmentally friendly activities research has shown that introducing external incentives to encourage pro social behavior such as monetary rewards or regulation may crowd out voluntary pro social activity this has implications for the appropriate design and use of such incentive based programs this study investigates motivational crowding out in the case of conservation auctions a relatively new tool that provides monetary incentives to encourage landowners to adopt environmentally friendly management practices our experimental evidence shows that the introduction and subsequent removal of a conservation auction significantly reduces voluntary provision of environmental quality via monetary donations to an environmental charity compared to a control group that does not experience an auction we also attempt to examine some economic theories of behavior that explain this effect according to either individual motivations or social interactions and our initial exploration finds that crowding out occurs regardless of whether or not participants have opportunities to interact with one another during the experiment

networks in the modern economy mexican migrants in the u s labor market this paper attempts to identify job networks among mexican migrants in the u s labor market the empirical analysis uses data on migration patterns and labor market outcomes based on a sample of individuals belonging to multiple origin communities in mexico over a long period of time each community s network is measured by the proportion of the sampled individuals who are located at the destination the united states in any year we verify that the same individual is more likely to be employed and to hold a higher paying nonagricultural job when his network is exogenously larger by including individual fixed effects in the employment and occupation regressions and by using rainfall in the origin community as an instrument for the size of the network at the destination

income fluctuation and asymmetric information an example of a repeated principal agent problem we examine a simple repeated principal agent model with discounting there are a risk averse borrower with an unobservable random income and a risk neutral lender the efficient contract is characterized it tends to the first best constant consumption contract as the discount factor tends to one and the time horizon extends to infinity if the time horizon is infinite and the contract is legally enforceable the borrower s utility becomes arbitrarily negative with probability one if the borrower has constant absolute risk aversion consumption is transferred between any two states at a constant interest rate which is less than the rate of time preference

political economy of mechanisms we study the optimal mirrlees taxation problem in a dynamic economy in contrast to the standard approach where the taxation mechanism is operated by a benevolent planner with full commitment power we focus on economies in which policy decisions are made by self interested politicians who cannot commit to policies the society controls politicians using elections we show that the provision of incentives to politicians can be partly separated from redistribution across agents and that political economy constraints can be modeled as introducing additional aggregate distortions in the dynamic mirrlees problem we provide conditions under which the political economy distortions persist or disappear in the long run if the politicians are as patient as the agents the best sustainable mechanism leads to an asymptotic allocation where the aggregate distortions arising from political economy disappear in contrast when politicians are less patient than the citizens positive aggregate labor and capital taxes remain even asymptotically we conclude by providing a brief comparison of centralized

capturing the least costly way of reducing pollution a shadow price approach abstract the production analysis literature is increasingly concerned with estimating marginal abatement costs yet most studies do not emphasize the ways in which pollutants may be reduced and their costs which makes them unable to identify the least costly compliance strategy this paper utilizes the materials balance principle to relate pollution to the employment of material inputs a production model which allows input and output substitution downscaling of operations pollution control and emission permits purchases as compliance strategies is proposed and the implications of joint and non joint pollution controls for the trade off between pollutants and desirable outputs are considered marginal abatement costs reflecting the least costly way of compliance are derived by exploiting the duality between the directional distance function and the profit function

imperfect commitment altruism and the family evidence from transfer behavior in low income rural areas in this paper we examine empirically whether risk pooling is more advantageous among altruistic compared to selfish agents in a framework where individuals cannot make binding commitments in particular we incorporate altuism into a model of risk sharing under imperfect commitment and use simulation methods to establish tests of the roles of both altruism and commitment problems in determining the extent of insurance and the intertemporal movements in interhousehold transfers the tests are carried out using three panel data sets from two countries of rural south asia that provide detailed information on transfers and enable the measurement of income shocks the estimates provide strong support for the notion that imperfect commitment substantially constrains informal transfer arrangements whether kin based or not but also provide evidence that altruism plays an important role in ameliorating commitment constraints and thus in increasing the gains from income pooling

self selection and pareto efficient taxation abstract this paper analyses the set of pareto efficient tax structures the formulation of the problem as one of self selection not only shows more clearly the similarity between this problem and a number of other problems such as the optimal pricing of a monopolist which have recently been the subject of extensive research but also allows the derivation of a number of new results we establish i under fairly weak conditions randomization of tax structures is desirable ii if different individuals are not perfect substitutes for one another in production then the general equilibrium effects until now largely ignored in the literature of changes in the tax structure may be dominant in determining the optimal tax structure in particular if the relative wage of high ability and low ability individuals depends on the relative supplies of labor the optimal tax structure entails a negative marginal tax rate on the high ability individuals and a positive marginal tax rate on the low ability individuals the marnitude of which depends on the elasticity of substitution iii if individuals differ in their preferences pareto efficient taxation may entail negative marginal tax rates for high incomes while iv if wage income is stochastic the marginal tax rate at the upper end may be 100 our analysis thus makes clear that the main qualitative properties of the optimal tax structure to which earlier studies called attention are not robust to these attempts to make the theory more realistic