property rights externalities and resource degradation locating the tragedy abstract resource degradation in the third world is largely driven by the demands of farm households for fuelwood and land for agriculture since resources are often controlled through indigenous systems of property the tragedy of the commons has been used to explain resource degradation as a result private property is suggested as a solution to resource degradation a dynamic model capable of examining household incentives for resource use under private and common property is developed results of the model reject the conventional wisdom that gives rise to the presumed optimality of private individual property in natural resources and the correlated indictment of group management regimes

bioeconomics of sustainable harvest of competing species abstract the concept of maximum sustainable yield frontier msf is applied to a gause model of competing species maximizing the present value of economic rent under costless harvesting with positive discount rate implies optimal stock levels below the locus of msf stocks maximizing economic rent with positive harvesting costs and zero discount rate implies optimal stock levels above the locus of msf stocks it is shown how the optimal steady state stock levels are altered by changes in the exogenous discount rate harvest prices and harvest costs optimal harvesting might imply harvesting of one of the two species at a loss

externalities expectations and pigouvian taxes this article derives pigouvian type corrective measures for reciprocal externalities when non nash behavior characterizes the participants these reciprocal externalities may involve various kinds of environmental pollutants such as acid rain a comparison between corrective measures for nash and non nash behavior demonstrates that positive conjectures regarding the other agent s externality generating activity have an expectation internalizing influence that usually reduces the required corrective measures negative conjectures e g free riding expectations however have an expectation externalizing effect that increases the required corrective measures the article analyzes both two person and n person externalities 13 references 3 figures 1 table

heterogeneity returns to scale and collective action i analyze the effects of resource inequality and valuation heterogeneity on the provision of public goods with increasing or decreasing returns to scale in production the existing literature typically takes the agents characteristics as given and known to the researcher in contrast this paper compares collective action provision across groups of agents with resources and valuations for the public good drawn from different known joint distributions specifically i characterize the expected equilibrium public good level as function of various distributional properties and moments a resource valuation distribution that first order stochastically dominates another distribution always results in higher expected public good provision level independent of the production technology with decreasing returns to scale in the public good production higher resource inequality results in higher expected provision with increasing returns the same result holds when the mean resource level is relatively low but expected provision decreases in inequality when the mean resource level is high a parallel result holds for agents valuations l auteur analyse les effets de l inegalite des ressources et de l heterogeneite dans l evaluation de biens publics dont la production se fait avec des rendements croissants et decroissants a l echelle la litterature specialisee suggere habituellement que les caracteristiques des agents sont donnees et connues du chercheur a contrario ce memoire compare l action collective de groupes d agents dont les ressources et les evaluations du bien public sont tirees de distributions conjointes connues specifiquement le niveau d equilibre anticipe du bien public est fonction de divers moments et proprietes de ces distributions une distribution conjointe ressources evaluations qui en domine une autre au sens stochastique de premier ordre resulte toujours en un niveau de bien public anticipe plus eleve quelle que soit la technologie de production quand les rendements a l echelle sont decroissants une inegalite de ressources plus grande resulte en un niveau de bien public anticipe plus eleve quand les rendements sont croissants le meme resultat s ensuit si le niveau moyen de la ressource est relativement bas mais le niveau de bien public anticipe decroit quand le niveau moyen de la ressource est eleve des resultats paralleles sont notes pour ce qui est des evaluations du bien public par les agents

the theory of public goods non nash behaviour abstract most treatments of equilibrium public goods provision assume zero conjectural variations in the sense that each individual regards the behaviour of the rest of the community as independent of his own this paper introduces nonzero conjectural variations into the model a diagram is introduced which can depict both the individual s and the community s equilibrium in the presence of nonzero conjectural variations equilibrium and optimal outcomes are compared and a specific functional form is used to investigate the effect of community size on the nature of equilibrium finally we discuss the requirement that conjectures should be consistent

expectations the commons and optimal group size abstract this article derives a formula for the optimal number of exploiters of a commons whose output is sold in an imperfectly competitive market and whose exploiters hold nonzero or non nash conjectures we express the optimal number of exploiters in terms of the conjecture the elasticity of input productivity and the price elasticity of market demand consistent conjectures those that agree with reality imply the full tragedy of the commons and zero profits for the exploiters

the impact of the correlation between health expenditure and survival probability on the demand for insurance abstract this paper studies the effects of health shocks on the demand for health insurance and annuities along with precautionary saving in a dynamic life cycle model i argue that when the health shock can simultaneously increase health expenses and reduce longevity rational agents would neither fully insure their uncertain health expenses nor fully annuitize their wealth because the correlation between health expenses and longevity provides a self insurance channel for both uncertainties that is when the agent is hit by a health shock which simultaneously increases health expenses and reduces longevity she can use the resources originally saved for consumption in the reduced period of life to pay for the increased health expenses since the two uncertainties partially offset each other the precautionary saving generated in the model should be smaller than in a standard model without the correlation between health expenses and longevity in a quantitative life cycle model calibrated using the medical expenditure panel survey dataset i find that the health expenses are highly correlated with the survival probabilities and this correlation significantly reduces the demand for actuarially fair health insurance while its impact on the demand for annuities and precautionary saving is relatively small

uncertain medical expenses and precautionary saving near the end of the life cycle this paper introduces a dynamic structural model of household consumption decisions in which elderly families consider the effects of uncertain future medical expenses when deciding current levels of consumption the model with uncertain medical expenses implies a potentially important role for precautionary saving incentives to explain slow rates of dissaving among elderly americans during retirement rather than just simulating the stochastic dynamic model preference parameters are estimated using panel data on health wealth and expenditures for retired families the health uncertainty model predicts consumption levels closer to observed expenditures than a life cycle model with uncertain longevity however elderly families typically dissave their financial assets more slowly than even the baseline health uncertainty model predicts is optimal

state sponsored violence as a tragedy of the commons england s privateering wars with france and spain 1625 1630 the tragedy of the commons is the familiar problem that open access to a common property resource leads to overexploitation and to zero profits a commons model is applied to an example of state sponsored private violence the practice of privateering or licensed piracy it is predicted that the presence of uncertainty about the value of the prey will reduce the amount of exploitation effort and that industry profits may be positive due to both uncertainty and heterogeneous exploiters using data from england s wars with france and spain between 1625 and 1630 the model suggests that the commons represented by enemy merchant shipping was not overexploited and that privateering profits were positive the dynamic paths of privateering effort ships seized and individual firm profits were however consistent with the normal expectation that commons exploitation will peak and fall as competition drives down returns through entry

on the severity of economic downturns lessons from cross country evidence abstract we measure the severity of recessions as a function of their amplitude and duration within a quantile regression framework we assess what causes economic downturns to be more or less severe we find that the most severe downturns have striking similarities regarding cumulated domestic credit and large current account deficits

the commons and the optimal number of firms the problem of the commons is a frequently cited example of market failure in which exploiters pursuit of profits does not lead to the attainment of a social or pareto optimum in particular a free access equilibrium induces an unrestricted number of exploiters or firms to equate the variable input s average product instead of its marginal product to the input s real rental rate hence the rents of the variable input are driven to zero haveman 1973 1 when the number of firms in a commons is unrestricted the scarce factor e g the fishery the hunting ground is not imputed a rent a social optimum can be achieved if a single firm exploits a commons and sells its output in a perfectly competitive market weitzman 1974 the purpose of this note is to derive an expression for the optimal number of firms exploiting a commons when the resulting output is sold in an imperfectly competitive market 2 since demand inelasticity due to monopoly power leads to overconservation while an increase in the number of exploiting firms typically leads to underconservation a finite number of firms for a commons can be found corresponding to a social or pareto optimum in particular the optimum number of firms depends directly on the elasticity of the input productivity and inversely on the price elasticity of market demand

health care reform or more affordable health care this article investigates the impact on the u s economy of making health care more affordable we compare health care cost reductions with the patient protection and affordable care act aca using a rich life cycle general equilibrium model with heterogeneous agents we evaluate a wide range of cost reductions ranging from 0 64 realistic and feasible to 29 5 equivalence with oecd our results show that the aca is more effective in reducing uninsured population than all cost reductions considered this result holds throughout the life cycle and for the most fragile part of the population the poorest the less educated and those with bad health realistic and feasible cost reductions are less welfare improving than the aca the increase of welfare induced by the reform is around 7 8 times higher than the increase provided by cost reductions besides the poorer are more benefited than the richer after the reform while the opposite occurs after cost reductions finally to obtain the same welfare increase of the aca medical costs have to decrease by 5 21 a very hard task these results provide support for the aca against opponents who might present cost reductions as alternatives

is the 2007 u s sub prime financial crisis so different an international historical comparison the first major financial crisis of the twentyfirst century involves esoteric instruments unaware regulators and skittish investors it also follows a well trodden path laid down by centuries of financial folly is the special prob lem of sub prime mortgages really different our examination of the longer historical record which is part of a larger effort on cur rency and debt crises finds stunning qualitative and quantitative parallels across a number of standard financial crisis indicators to name a few the run up in us equity and housing prices that graciela l kaminsky and reinhart 1999 find to be the best leading indicators of crisis in countries experiencing large capital inflows closely tracks the average of the previous 18 post world war ii banking crises in industrial countries so too does the inverted v shape of real growth in the years prior to the crisis despite widespread concern about the effects on national debt of the tax cuts of the early 2000s the run up in us public debt is actually some what below the average of other crisis episodes in contrast the pattern of us current account deficits is markedly worse at this juncture the book is still open on how the current dislocations in the united states will play out the precedent found in the aftermath of other episodes suggests that the strains can be quite severe depending especially on the initial degree of trauma to the financial system and to some extent the policy response the average drop in real per capita output growth is over 2 percent and it typically takes two years to return to trend for the five most catastrophic cases which include episodes in finland japan

medical care costs how much welfare loss hardly a week goes by without a front page newspaper article on rising health care costs and the uninsured in this article i focus mainly on costs arguing that the issue has been somewhat misconceived while the level of medical care spending in the u s is a cause for concern the welfare losses associated with rises in that level of spending may not be as large as the public rhetoric can make them seem in fact cost containment may not be as urgent as is widely supposed and some proposed cost containment policies may result in welfare losses for the insured and even increase the number of uninsured

common pool equities an arbitrage based non cooperative solution to the common pool resource problem abstract it is proposed that a new type of property right termed a common pool equity can solve the common pool resource problem this equity may be presented to any firm that extracts from the resource for a share in profits it is shown that a profit arbitrage condition ensures that the market and socially efficient solutions correspond whenever market power is absent the cost externalities are fully internalized

pure public goods versus commons benefit cost duality sandler and arce 1 pure public goods versus commons benefit cost duality by todd sandler school of international relations university of southern california von kleinsmid center 330 los angeles ca 90089 0043 tsandler usc edu 213 740 9695 213 742 0281 fax and daniel g arce m department of economics rhodes college 2000 n parkway memphis tn 38112 1690 arce rhodes edu 901 843 3121 901 843 3736 fax final revision november 2002 sandler is the robert r and katheryn a dockson professor of international relations economics university of southern california and arce is the robert d mccallum distinguished professor of economics business rhodes college sandler s and arce s research was funded through the dockson and mccallum endowments respectively we have profited from the helpful comments of two anonymous referees

dissecting the cycle a methodological investigation following burns and mitchell we define the cycle as a pattern in the level of aggregate economic activity an algorithm to locate turning points is developed as is a new measure of pro cyclicality a link between turning points and the moments of the series is established thereby providing the statistical foundation that burns and mitchell s work lacked using these tools we are able to dissect cycles in terms of the contributions made by trend growth volatility serial correlation and non linear effects we dissect several models and find little evidence that certain non linear effects are important to the nature of business cycles

on the social efficiency of conflict abstract in sharp contrast with the economic literature on conflict this paper shows that confrontation may be efficiency enhancing conditions are derived under which a contest over the exclusive control of a resource pareto dominates peaceful access

the role of asset testing in public health insurance reform abstract starting slowly with the 1996 welfare reform act and culminating in the 2010 affordable care act means tested public health insurance eligibility expanded to include adults in low income families regardless of their asset holdings this paper quantifies the effects of these eligibility expansions within the context of the 2010 affordable care act i construct a dynamic stochastic general equilibrium model with indivisible labor supply expanded to include an endogenous household choice of health insurance coverage and calibrate it to u s data i establish that changes in the distribution of labor and welfare associated with removal of asset testing are driven by exit of high productivity and high wealth households from the labor market i then expand my analysis to the 2010 affordable care act to demonstrate that removal of asset testing is critical to the obtained results even when combined with other provisions of the act finally i find that a simple asset test for eligibility of health insurance transfers undoes the distortion to the household labor supply decision among high productivity types these results are robust to the introduction of employer premium contributions an independent health insurance market and idiosyncratic shocks to eligibility for employment based health insurance

endogenous conjectural variations in oligopoly abstract conventional oligopoly theories provide no mechanism for oligopolists to learn from their experience of other firms behavior in forming conjectural variations this paper explores two approaches to the solution of this problem in the first the consistent conjectures approach oligopolists passively react to changes in other firms outputs so as to keep their own profits at a maximum other firms correctly anticipate these reactions in the second approach the matching behavior approach firms actively choose reactions which will induce other firms to reduce their outputs again these reactions are correctly anticipated by the other firms the implications of these alternative models are derived and contrasted with the implications of the cournot and joint profit maximization models

tropical deforestation markets and market failures activities to curb deforestation yield private goods country specific public goods and global public goods markets can operate for the private goods while nations are motivated to strike bargains with one another over country specific public goods suboptimality stems from the global public goods and the positive externalities associated with preservation activities this suboptimality can be attenuated if the developed countries establish property rights to genetic material gathered from the rain forests since much of the global public benefits is derived by the developed countries they are in a weak bargaining position with respect to the shrinking rain forests

fuelwood subsistence foraging and the decline of common property abstract ideally common property can adapt to particularities in the social and physical environment to create environmentally sustainable regimes in practice common fuelwood foraging has been subject to numerous problems intimately linked to the historically changing role of common property schematic histories of fuelwood and forests in europe and java illustrate how common property systems have been undermined and the different implications their dissolution can have both cases indicate that fuelwood problems may be best interpreted within the rubric of subsistence foraging and the decline of common property rather than that of energy shortage and tree mismanagement

retirement wealth and lifetime earnings this article argues that a satisfactory theory of wealth inequality should account not only for the marginal distribution of wealth but also for the joint distribution of wealth and earnings the article describes the joint distribution of retirement wealth and lifetime earnings in the panel study of income dynamics it then evaluates the ability of a stochastic life cycle model to account for key features of this distribution the life cycle model fails to account for three key features of the data 1 the correlation between lifetime earnings and retirement wealth is too high 2 the wealth gaps between earnings rich and earnings poor households are too large 3 wealth inequality among households with similar lifetime earnings is too small models in which households differ in rates of return or time preferences account much better for the joint distribution of retirement wealth and lifetime earnings

harvest uncertainty and the tragedy of the commons abstract this paper demonstrates that a fixed number of risk averse firms faced with harvest uncertainty owing to resource stock uncertainty will typically reduce their exploitation of a commons in addition the total exploitation of the industry will decrease when entry is permitted and uncertainty is compared with certainty this result holds for perfectly competitive output markets and also characterizes imperfectly competitive output markets with linear market demand and risk neutral firms in the latter case the socially optimum number of firms is determined based upon the degree of uncertainty the price elasticity of market demand and the elasticity of input productivity

the effects of health wealth and wages on labour supply and retirement behaviour this paper estimates a life cycle model of labour supply retirement and savings behaviour in which future health status and wages are uncertain individuals face a fixed cost of work and cannot borrow against future labour pension or social security income the method of simulated moments is used to match the life cycle profiles of labour force participation hours worked and assets that are estimated from the data to those that are generated by the model the model establishes that the tax structure of the social security system and pensions are key determinants of the high observed job exit rates at ages 62 and 65 removing the tax wedge embedded in the social security earnings test for individuals aged 65 and older would delay job exit by almost one year by contrast social security benefit levels health and borrowing constraints are less important determinants of job exit at older ages for example reducing social security benefits by 20 would cause workers to delay exit from the labour force by only three months

centralized and decentralized management of local common pool resources in the developing world experimental evidence from fishing communities in colombia this paper uses experimental data to test for a complementary relationship between formal regulations imposed on a community to conserve a local natural resource and nonbinding verbal agreements to do the same our experiments were conducted in the field in three regions of colombia each group of five subjects played 10 rounds of an open access common pool resource game and 10 additional rounds under one of five institutions communication alone two external regulations that differed by the level of enforcement and communication combined with each of the two regulations our results suggest that the hypothesis of a complementary relationship between communication and external regulation is supported for some combinations of regions and regulations but cannot be supported in general we therefore conclude that the determination of whether formal regulations and informal communication are complementary must be made on a community by community basis

collective contests for commons and club goods abstract this paper focuses on collective contests for commons and club goods our main objective is to examine in this context the effect of group size on its performance the main results specify conditions for the existence non existence of the group size paradox namely the situation where a larger group is less more effective in pursuing its interest because of despite the combined effect of the incentives that result in the free riding problem and the tragedy of the commons the paper also explains under what circumstances there exists a bias towards excessive or inadequate winning group size finally it examines the effect of restricted excludability of the commons good within the winning group on the relationship between group size and its winning probability

what motivates common pool resource users experimental evidence from the field this paper develops and tests several models of pure nash strategies of individuals who extract from a common pool resource when they are motivated by a combination of self interest and other motivations such as altruism reciprocity inequity aversion and conformism we test whether an econometric summary of subjects strategies is consistent with one of these motivations using data from a series of common pool resource experiments conducted in three regions of colombia as expected average extraction levels are less than that predicted by a model of pure self interest but are nevertheless sub optimal moreover we find that a model of conformism with monotonically increasing best response functions best describes average strategies our empirical results are inconsistent with models of altruism reciprocity and inequity aversion

harvesting preemption industrial concentration and enclosure of national marine fisheries this paper explores how harvesting technology can affect firms internalisation of common pool externalities and the incentives for expanding firm s size focusing on supply side non pecuniary externalities our closed entry harvesting competition model suggests that when marginal harvesting costs are weakly sensitive to common pool externalities atomistic competition is likely to remain other things equal as the predominant industrial structure in the fishery the avenue for increasing industrial concentration is modelled via stackelberg leadership which offers the option of preempting rivals production in our static modelling a fishery subject to stackelberg signalling results in higher overfishing versus the case of a highly decentralised harvesting sector proxied by the use of nash conjectures given that static optimising behaviour could be interpreted as a result of entry controls and other fishing regulations being widely perceived as ineffective controls the obtained overfishing ranking suggests that in fisheries where strategic preemption in production is feasible but where entry controls and other important regulations on fishing effort are considered to be ineffective overfishing is likely to remain the predominant outcome even if other incentives promote evolution towards a more concentrated industry structure when the fishery is already overpopulated by numerous small firms whatever advantages large firms may have in terms of profitability numerous small scale fishermen tend to make up for in the political arena this imposes constraints on the politically feasible fishing regulations we use a second best welfare benchmark to illustrate resulting policy trade offs

the optimal number of firms in the commons a dynamic approach we consider a common property resource sold in imperfectly competitive markets there is a dynamic externality current harvests lower future stocks raising future harvest costs and a static crowding externality increasing industry size raises costs but lowers prices thus it has ambiguous welfare effects the optimal industry size typically changes over time so that a first best outcome cannot be obtained with a fixed number of firms single firm exploitation is optimal only under special circumstances the socially optimal open loop steady state industry size corresponds to the static optimum both generally differ from the closed loop steady state optimum

dynamic voluntary provision of public goods abstract the paper considers a dynamic public goods problem in which individuals contributions are accumulated over time analyzing the infinite duration dynamic game with continuous contributions and flow benefits the paper demonstrates that the free riding problem is aggravated when players contributions are conditional on the observable collective contributions hence without commitment an additional incentive to depress contributions arises a current contributor can free ride on all future contributions as well as on current ones

a non cournot model of voluntary collective action the interaction of selfish rational actors in the provision of a public good is analyzed in an attempt to explain recent experimental findings as well as real world cases of voluntary collective action the model which allows for more sophisticated behavior than that assumed by the conventional cournot theory predicts a higher level of collective action that that theory the impacts of income effects and of the price elasticity of demand for the public good are given special emphasis