pollution added credit trading pact new dimensions in emissions trading abstract to date sources of hazardous toxic or otherwise harmful emissions have been regulated on a pollutant by pollutant basis environmental policies even the more advanced incentive based programs have focused on individual substances rather than on the overall environmental problem to which the substances contribute this has produced results that are less economically efficient and ecologically effective than is desirable a more comprehensive approach combines the principles of emission reduction credit trading with advances made recently in the field of environmental impact assessment to yield an advanced form of inter pollutant trading which we refer to as pollution added credit trading pact pact incorporates a method for estimating the total environmental harm generated pollution added by a facility emitting a variety of pollutants weightings that reflect relative harm are used to calculate total pollution added each facility covered by pact would receive annual allowances for total pollution added that they could discharge to the environment as with existing emissions trading programs surplus allowances could be sold and shortfalls would be covered by purchasing other facilities surplus allowances pact is more efficient than single pollutant emissions trading in that it captures differences in marginal reduction costs that exist between pollutants as well as between facilities it is more ecologically effective because it focuses on the overall environmental problem rather than on the individual pollutants that contribute to the problem

markets for pollution control when firms are noncompliant the problem of noncompliance and enforcement in transferable discharge permit tdp markets has not received much attention this paper examines the consequences of noncompliance for a tdp market given fairly general assumptions about the characteristics of the enforcement policy in place the analysis reveals that when firms are noncompliant tdp markets retain their efficiency property only under some fairly stringent conditions the effect of noncompliance on the equilibrium permit price raises some important questions about the ability of a tdp market to achieve and remain in equilibrium when firms are noncompliant

the effect of annuity insurance on savings and inequality this paper examines the amount of precautionary savings and wealth inequality arising from life span uncertainty by comparing saving behavior under perfect insurance arrangements with that arising under imperfect arrangements namely when longevity risk can be pooled only with members of one s own family the central findings of the paper are that 1 perfecting insurance arrangements can sharply lower savings in both intergenerationally altruistic and life cycle economies and that 2 in altruistic economies perfecting annuity insurance can greatly influence inequality indeed in the long run in our model switching from imperfect family insurance to perfect insurance can mean the difference between absolute inequality and absolute equality

a panel analysis of job changes and unemployment abstract this paper tests for state dependence in histories of unemployment and job mobility from the first six waves of the german socio economic panel soep transitions between states of employment and unemployment are modelled as outcomes of binomial probit processes which are first and higher order markov the use of simulation estimation allows quite general intertemporal covariance structures in order to capture individual heterogeneity it is investigated how differences in human capital and other personal characteristics and macro or industry determinants such as regional unemployment growth and immigration pressure affect labour mobility

the effect of annuity insurance and savings and inequality this paper examines the amount of precautionary savings and wealth inequality arising from life span uncertainty by comparing saving behavior under perfect insurance arrangements with that arising under imperfect arrangements namely when longevity risk can be pooled only with members of one s own family the central findings of the paper are 1 perfecting insurance arrangements can lower savings in intergenerationally altruistic and life cycle economies and 2 in altruistic economies perfecting annuity insurance can influence in equality indeed in the long run in the model switching from imperfect family insurance to perfect insurance can mean the difference between absolute inequality and absolute equality copyright 1986 by university of chicago press

implementing marketable emissions permits the environmental protection agency is introducing bubbles offsets and banks as a way of controlling pollution with market incentives to obtain standards for each source and guide the reallocation of emissions the new method is not a true market because polluters must go through the permitting procedure in order to trade emission allowances this study examines whether an efficient market without source by source review is feasible it considers the importance of enough participants competitiveness sensitivity to geographic emission patterns and trading flexibility to sustain marketable permits the design features that address these problems are permit life market definition market initiation and market operation a stable permit market eliminates some of the uncertainties in decision making because it allows firms to select a preferred level of risk 9 references dck

designing economic instruments for the environment in a decentralized fiscal system designing economic instruments for the environment when external effects are important markets will be inefficient and economists have considered several broad classes of economic instruments to correct these inefficiencies however the standard economic analysis has tended to neglect important distinctions and interactions between the geographic scope of pollutants the enforcement authority of various levels of government and the fiscal responsibilities of the levels of government for example externalities generated in a particular local area may be confined to the local area or may spill over to other jurisdictions also local governments may be well informed about how best to regulate or enforce pollution control within their jurisdiction but they may not consider the effects of their actions on other jurisdictions finally the existence of locally generated waste emissions affects the appropriate assignment of both expenditure and tax responsibilities among levels of government the standard analysis therefore focuses mainly upon an aggregate or national perspective it typically ignores the possibility that the externality may be created and addressed by local governments and it does not consider the implications of decentralization for the design of economic instruments targeted at environmental problems this paper examines the implications of decentralization for the design of corrective policies that is how does one design economic instruments in a decentralized fiscal system in which externalities exist at the local level and in which subnational governments have the power to provide local public services as well as to choose tax instruments that can both finance these expenditures and correct the market failures of externalities

will markets direct investments under the kyoto protocol lessons from the activities implemented jointly pilots under the kyoto protocol countries can meet treaty obligations by investing in projects that reduce or sequester greenhouse gases elsewhere prior to ratification treaty participants agreed to launch country based pilot projects referred to collectively as activities implemented jointly aij to test novel aspects of the project related provisions relying on a ten year history of projects we investigate the determinants of aij investment our findings suggest that review agency preferences related to national political objectives and possibly deeper cultural ties influenced project selection and limited the number of aij projects bilateral ties also appear to have affected investment decisions directly possibly because of related transaction costs the results suggest an investment process different from the assumptions that underlie well known estimates of cost savings related to the protocol s flexibility mechanisms we conclude that if approaches developed under the aij programs to approve projects are retained the scale of investment under kyoto s flexibility provisions and their cost savings will be less than what is generally anticipated and the pattern of investment less driven by abatement costs

time aggregation and state dependence in welfare receipt dynamic discrete choice models are an important tool in studies of state dependence in benefit receipt a common assumption of such models is that benefit receipt sequences follow a conditional markov process this property has implications for how estimated period to period benefit transition probabilities should relate when receipt processes are aggregated over time this paper assesses whether the conditional markov property holds in welfare benefit receipt dynamics in norway using high quality monthly data from administrative records we find that the standard conditional markov model is seriously misspecified estimated state dependence is affected substantially by the chosen time unit of analysis with the average treatment effect of past benefit receipt increasing with the level of aggregation the model can be improved considerably by permitting richer types of benefit dynamics we find strong evidence for both duration and occurrence dependence in benefit receipt allowing for heterogeneity in the entry and persistence processes we find important disparities in the effects of observed and persistent unobserved characteristics based on our preferred model the month to month persistence probability in benefit receipt for a first time entrant is 37 percentage points higher than the entry rate of an individual without previous benefit receipt over a 12 month period this corresponds to an average treatment effect of 5 percentage points

rebound effects of new irrigation technologies the role of water rights we study how institutions such as water rights can complement new irrigation technologies in promoting the sustainability of u s agriculture using data from the ogallala high plains aquifer region of kansas we find that water extraction moderately increases after adopting low energy precise application lepa irrigation and this rebound effect is in general higher for farmers with larger water rights about half of the lepa s rebound effects arise because adopters tend to irrigate more land and grow more water intensive crops with the remaining half attributable to more intensive irrigation farmers with greater water rights use more water with two thirds of the effects arising from irrigating larger land areas and one third of the effects attributable to more intensive irrigation a 10 reduction of water rights will reduce water use by 5 in the long run and if the reduction targets the majority of the water rights which lie between 100 and 500 af lepa s rebound effect decreases by 15 4 finally we find that farmers have an incentive to apply a small amount of water in order to preserve their water rights but the associated water waste is insignificant

government intervention as a bequest substitute abstract a subsequent generations model is used in order to characterize consumption allocation under the future generation s income uncertainty altruistic concerns towards future generations give rise to precautionary bequests which act as a hedge on risk it is shown that given a first order correlation between mean future income and the present generation s income government can provide a pareto improvement through a tax transfer policy with universal participation this policy acts as a substitute for precautionary bequests distributional aspects of government tax transfer policy are also discussed

low pay dynamics and transition probabilities this paper models low pay transitions in britain using a bivariate probit model with endogenous selection to address the initial conditions problem and parental variables as instruments the exogeneity of the initial state is strongly rejected and results in considerable overstatement of the effects of explanatory factors the probability of being low paid depends strongly on low pay in the previous year restricting attention to those who remain employees results in an overstatement of the probability of the low paid moving up the earnings distribution but is not found to have much effect on the estimated effects of explanatory variables

income uncertainty and the demand for annuities abstract two well known results concerning the demand for annuities in an overlapping generations model are i egoistic agents should annuitize all their wealth and ii altruistic agents should segment their savings between riskless bonds for bequests and annuities for own consumption this paper extends the analysis by considering income uncertainty it is shown that while the segmentation result holds under future generation s income uncertainty fgiu altruistic agents do not segment their savings in the presence of second period income uncertainty spiu the intuition for this result is that income uncertainty in the second period of life is contingent on being alive and therefore at the optimum the covariance between one s offspring s consumption and life uncertainty is not zero as in the case of certainty and fgiu the effects of precautionary savings on the demand for annuities are also analyzed

measuring state dependence in individual poverty histories when there is feedback to employment status and household composition this paper argues that the assumption of strict exogeneity which is usually invoked in estimating models of state dependence with unobserved heterogeneity is violated in the poverty context as important variables determining contemporaneous poverty status in particular employment status and household composition are likely to be influenced by past poverty outcomes therefore a model of state dependence is developed that explicitly allows for possible feedback effects from past poverty to future employment and household composition outcomes empirical results based on data from the german socio economic panel gsoep suggest that there are indeed such feedback effects and that failure to take them into account may lead to biased estimates of the state dependence effect copyright 2009 john wiley sons ltd

simple solutions to the initial conditions problem in dynamic nonlinear panel data models with unobserved heterogeneity i study a simple widely applicable approach to handling the initial conditions problem in dynamic nonlinear unobserved effects models rather than attempting to obtain the joint distribution of all outcomes of the endogenous variables i propose finding the distribution conditional on the initial value and the observed history of strictly exogenous explanatory variables the approach is flexible and results in simple estimation strategies for at least three leading dynamic nonlinear models probit tobit and poisson regression i treat the general problem of estimating average partial effects and show that simple estimators exist for important special cases copyright 2005 john wiley sons ltd

persistence of innovation discriminating between types of innovation and sources of state dependence abstract this paper advances current research on the persistence of innovation drawing on a panel data set constructed from three waves of the german part of the community innovation survey covering the time span from 2002 to 2008 i e cis iv cis 2007 and cis 2009 we explore persistence patterns for various types of innovation i e organizational product and process innovation and allowing for the moderating impact of firm level characteristics we use the ascertained patterns of persistence to comparatively evaluate various sources and underlying theoretical accounts of state dependence

the dynamics of health in the british household panel survey this paper considers the dynamics of a categorical indicator of self assessed health using eight waves 1991 1998 of the british household panel survey bhps our analysis has three focal points the relative contributions of state dependence and heterogeneity in explaining the dynamics of health the existence and consequences of health related sample attrition and the investigation of the effects of measures of socioeconomic status with a particular focus on educational attainment and income to investigate these issues we use dynamic panel ordered probit models there is clear evidence of health related attrition in the data but this does not distort the estimates of state dependence and of the socioeconomic gradient in health the models show strong positive state dependence and heterogeneity accounts for around 30 of the unexplained variation in health copyright 2004 john wiley sons ltd

the family as an incomplete annuities market families can self insure against uncertain dates of death through implicit or explicit agreements with respect to consumption and interfamily transfers interfamily transfers need have nothing to do with altruistic feelings they may simply reflect risk sharing behavior of completely selfish family members although family annuity markets are incomplete even small families can substitute by more than 70 percent for perfect market annuities given adverse selection and transaction costs family risk pooling may be preferred to public market annuities in the absence of public annuities these risk sharing arrangements provide powerful incentives for marriage and family formation

income uncertainty bequests and annuities abstract life uncertainty and income uncertainty are modeled simultaneously in order to analyze the influence of perfecting income insurance in the size of bequests and the demand for annuities the main result shows that government intervention aimed at providing intergenerational risk sharing acts as a bequest substitute and if annuities are available reduces the demand for annuities

is the ladder sticky measuring semi parametrically state dependence in earnings mobility employing the u s data for the 1990 s we disentangle state dependence from unobserved heterogeneity in earnings mobility the fixed effects dynamic multinomial logit utilized to model earnings quintiles dynamics fits the data very well much more so than the autocorrelated dynamic ordered probit unordered models should thus be preferred to study earnings mobility state dependence is found to be significant it has a protective anti fall effect at the top of the distribution and a detrimental anti rise effect at the bottom consequently the difficulty of climbing the ladder is not exclusively a question of individual characteristics public policies could thus be implemented to improve information about individuals ability and job offers and to design more efficient wage setting institutions

intergenerational risk sharing abstract in this paper we examine government debt and tax transfer policies that can be improve the allocation of risk between generations markets cannot allocate risk efficiently between two generations whenever the two generations are not both alive prior to the occurence of a stochastic event this implies that government policies transferring risk between generations have the potential to create first order welfare improvements our model provides a non keynesian justification for the debt finance of wars and recessions as well as an added rationale for social security type tax transfer schemes which aid unlucky generations e g the depression generation at the expense of luckier generations

state dependence serial correlation and heterogeneity in intertemporal labor force participation of married women a dynamic search framework is developed to analyze the intertemporal labor force participation behavior of married women using longitudinal data to allow for a rich dynamic structure the sensitivity to alternative distributional assumptions is evaluated using linear probability and probit models the dynamic probit models are estimated using maximum simulated likelihood msl estimation to overcome the computational difficulties inherent in maximum likelihood estimation of models with nontrivial error structures the results find that participation decisions are characterized by significant state dependence unobserved heterogeneity and negative serial correlation in the error component the hypothesis that fertility decisions are exogenous to women s participation decisions is rejected when dynamics are ignored however there is no evidence against this hypothesis in dynamic model specifications women s participation response is stronger to permanent than current nonlabor income reflecting unobserved taste factors

state dependence individual heterogeneity and the choice of employment status evidence from korea abstractfocusing on the individual heterogeneity this article examines the causes of an individual s employment status choice and the extent of state dependence in the korean labour market we estimate a dynamic multinomial logit model using the panel data drawn from the first to fifteenth wave of the korean labour and income panel study the results suggest the presence of state dependence individual characteristics and growth background have a significant effect on the choice of employment status gender is still an important employment factor males are more likely to be employed and this gender effect is highest for regular employment re one s educational attainment and age operate in opposite directions that is educational attainment age has a positive negative impact on the choice of a regular job and a negative positive impact on the choice of a non regular job contrary to our expectations a wealthy family background reduces the probability of individuals being wage workers and rais

uncertainty and optimal social security systems this paper examines the annuity aspect of social security within the framework of an overlapping generations model the duration of life is assumed to be uncertain under a fully funded system demand for social security is determined by each generation so as to maximize expected lifetime utility taking into account the welfare of future generations under a pay as you go system with intergenerational transfers demand for retirement benefits by the working population takes into account taxes paid by descendants it is shown that the two modes of finance are equivalent in terms of all real aggregates effects of changes in expected lifetime and in the birth rate are analyzed starting at the optimal level a compulsory balanced increase in social security taxes and benefits is shown to increase short run savings

trade offs in designing markets with multiple objectives abstract this paper explores some of the problems involved in designing markets with multiple objectives the first part of the paper considers the issue of how such markets are designed in theory while the second part reviews some evidence on actual applications in the field of air pollution control

economic prescriptions for environmental problems how the patient followed the doctor s orders o ne of the dangers with ivory tower theorizing is that it is easy to lose sight of the actual set of problems which need to be solved and the range of potential solutions as one who frequently engages in this exercise i can attest to this fact in my view this loss of sight has become increasingly evident in the theoretical structure underlying environmental economics which often emphasizes elegance at the expense of realism in this paper i will argue that both normative and positive theorizing could greatly benefit from a careful examination of the results of recent innovative approaches to environmental management the particular set of policies examined here involves two tools which have received widespread support from the economics community marketable permits and emission charges pigou 1932 dales 1968 kneese and schultze 1975 both tools represent ways to induce businesses to search for lower cost methods of achieving environmental standards they stand in stark contrast to the predominant command and control approach in which a regulator specifies the technology a firm must use to comply with regulations under highly restrictive conditions it can be shown that both of the economic approaches share the desirable feature that any gains in environmental quality will be obtained at the lowest possible cost baumol and oates 1975 until the 1960s these tools only existed on blackboards and in academic journals as products of the fertile imaginations of academics however some countries have recently begun to explore using these tools as part of a broader strategy for managing environmental problems

the persistence of energy poverty a dynamic probit analysis abstract this paper contributes to the growing literature on energy poverty in developing countries we use a dynamic probit estimator on three rounds of panel data from urban ethiopia to estimate a model of the probability of being energy poor and to investigate the persistence of energy poverty we also study the impact of energy price inflation which ethiopia experienced during 2007 2009 on energy use and energy poverty we find strong evidence of state dependence in energy poverty a household that is energy poor in one round is up to 16 more likely to be energy poor in the subsequent round dynamic probit regression results also suggest that an increase in the price of kerosene the most important fuel for the urban poor drives households into energy poverty a fractional response estimator for panel data which estimates the impact of energy prices on the proportion of energy obtained from clean sources also supports the finding on the adverse impact of energy price inflation households responded to the significant rise in the price of kerosene by consuming a large amount of charcoal which has been documented to have serious environmental climate and health consequences our results have significant implications for policies formulated to reduce energy poverty conserve biomass resources and promote energy transition in developing countries

the persistence of subjective poverty in urban ethiopia using panel data spanning 15 years this paper investigates the persistence and correlates of subjective and consumption poverty in urban ethiopia despite the decline in consumption poverty in recent years which has been linked to rapid economic growth subjective poverty has remained largely unchanged dynamic probit regression results show that households with a history of past poverty continue to perceive themselves as poor even if their material consumption improves our results also suggest that the relative economic position of households is a strong determinant of subjective poverty and having at least some type of employment reduces the likelihood that households will perceive themselves as poor even if they remain in objective poverty receiving remittances from abroad on the other hand does not reduce perceived poverty even if it raises material consumption we argue that any analysis to measure the impact of growth on welfare should encompass subjective measures as well

uncertainty resolution and the timing of annuity purchases abstract this paper considers the question of why the annuity market is thin a model is presented in which consumers have the option of purchasing annuities before discovering their survival probability they can then recontract the initial choice after the resolution of this form of uncertainty it is shown that consumers purchase insurance against their own survival probability type at a very young age and do not undertake further transactions this characterization is then used to analze the effects of introducing future income uncertainty and to investigate the trade off between old age insurance motive and portfilio flexibility

regulatory constraints on environmental markets abstract there have been several recent regulatory reforms aimed at promoting economic efficiency these reforms fall into two broad categories those aimed at promoting competition in specific industries and those aimed at addressing problems that cut across several industries this analysis examines two reforms that fall into the latter category both of these policies are specifically designed to enhance environmental quality while promoting cost savings the analysis focuses on the biases and inefficiencies associated with the use of these policies the paper concludes with a discussion of the possibility of designing more efficient alternatives in light of the political constraints that are imposed on regulators

modelling low income transitions we examine the determinants of low income transitions using first order markov models that control for initial conditions effects those found to be poor in the base year may be a non random sample and for attrition panel retention may also be non random our econometric model is a form of endogeneous switching regression and is fitted using simulated maximum likelihood methods the estimates derived from british panel data for the 1990s indicate that there is substantial genuine state dependence in poverty we also provide estimates of low income transition rates and lengths of poverty and non poverty spells for persons of different types

does poverty trap rural malagasy households this paper studies the determinants of poverty dynamics in several rural areas from madagascar a particular attention is devoted to testing if rural poverty persistence in madagascar could be explained by a vicious circle leading to a poverty trap annual poverty transitions retrieved from an original household panel data survey covering the 1996 2006 periods show that differences in household and environment characteristics are clearly associated with di erences in poverty transitions probabilities poverty vulnerable households have higher dependency ratio and are less educated they also show different income generating activities pattern they cultivate less market oriented crops and have more vulnerable activities such as agricultural wage work a markovian poverty transition model is used to evaluate the role of past poverty in this situation past poverty is allowed to have both an intercept and a slope effect on poverty transitions probabilities our results show that a substantial share of the di erences in household poverty transitions probabilities is attributable to past poverty status these results encourage the development of social protection to prevent households to fall into a poverty trap as well as speciffic measures to encourage paths out of poverty traps francais cet article etudie les determinants de la dynamique de la pauvrete dans plusieurs zones rurales de madagascar une attention particuliere est portee a l identification d un eventuel effet deletere de la pauvrete passee sur la pauvrete future pouvant conduire a un cercle vicieux de perpetuation de la pauvrete le papier se base sur l etude des transitions annuelles sur et sous le seuil de pauvrete observees sur un panel de menages ruraux malgaches entre 1996 et 2006 un modele markovien est utilise pour evaluer le role des caracteristiques des menages de l environnement et de la pauvrete passee dans la probabilite de passer sur ou sous le seuil de pauvrete les resultats montrent que certaines caracteristiques des menages et de l environnement sont clairement associees a differences dans les probabilites de transitions sur et sous le seuil de pauvrete en particulier les menages vulnerables a la pauvrete ont un rapport de dependance plus eleve sont moins eduques et ont une composition de revenus differentes ils sont notamment moins orientes vers les cultures agricoles et plus orientes vers des activites precaires comme le salariat agricole un effet deletere de la pauvrete passee sur le risque d etre pauvre dans le futur est egalement mis en evidence il passe a la fois par un effet de pente et un effet de niveau ces resultats soulignent la necessite de mettre en place des politiques specifiques contre la vulnerabilite a la pauvrete d une part et contre la pauvrete de long terme d autre part

the interrelated dynamics of unemployment and low wage employment this paper examines the extent of state dependence in unemployment and the role played in this by intervening low wage employment a range of dynamic random and fixed effects estimators are compared low wage employment is found to have almost as large an adverse effect as unemployment on future prospects and the difference in their effects is found to be insignificant evidence is presented that low wage jobs act as the main conduit for repeat unemployment and considerably increases its probability obtaining a higher wage job reduces the increased risk of repeat unemployment to insignificance

the role of intergenerational transfers in aggregate capital accumulation this paper uses historical u s data to directly estimate the contribution of intergenerational transfers to aggregate capital accumulation the evidence presented indicates that intergenerational transfers account for the vast majority of aggregate u s capital formation only a negligible fraction of actual capital accumulation can be traced to life cycle or hump savings a major difference between this study and previous investigations of this issue is the use of more accurate longitudinal age earnings and age consumption profiles these profiles are simply too flat to generate substantial life cycle savings this paper suggests the importance of and need for substantially greater research and data collection on intergenerational transfers life cycle models of savings that emphasize savings for retirement as the dominant form of capital accumulation should give way to models that illuminate the determinants of intergenerational transfers

designing economic instruments for the environment in a decentralized fiscal system when external effects are important markets will be inefficient and economists have considered several broad classes of economic instruments to correct these inefficiencies however the standard economic analysis has tended to neglect important distinctions and interactions between the geographic scope of pollutants the enforcement authority of various levels of government and the fiscal responsibilities of the levels of government for example externalities generated in a particular local area may be confined to the local area or may spill over to other jurisdictions also local governments may be well informed about how best to regulate or enforce pollution control within their jurisdiction but they may not consider the effects of their actions on other jurisdictions finally the existence of locally generated waste emissions affects the appropriate assignment of both expenditure and tax responsibilities among levels of government the standard analysis therefore focuses mainly upon an aggregate or national perspective it typically ignores the possibility that the externality may be created and addressed by local governments and it does not consider the implications of decentralization for the design of economic instruments targeted at environmental problems this paper examines the implications of decentralization for the design of corrective policies that is how does one design economic instruments in a decentralized fiscal system in which externalities exist at the local level and in which subnational governments have the power to provide local public services as well as to choose tax instruments that can both finance these expenditures and correct the market failures of externalities

market power and transferable property rights the appeal of using markets as a means of allocating scarce resources stems in large part from the assumption that a market will approximate the competitive ideal when competition is not a foregone conclusion the question naturally arises as to how a firm might manipulate the market to its own advantage this paper analyzes the issue of market power in the context of markets for transferable property rights first a model is developed that explains how a single firm with market power might exercise its influence this is followed by an examination of the model in the context of a particular policy problem the control of particulate sulfates in the los angeles region

state dependence and stickiness of sovereign credit ratings evidence from a panel of countries using data from moody s we examine three sources of sovereign credit ratings persistence true state dependence spurious state dependence and serial error correlation accounting for ratings persistence we also examine whether ratings were sticky or procyclical for two major crises the european debt crisis and the east asian crisis we set up a dynamic panel ordered probit model with autocorrelated disturbances and nonparametrically distributed random effects an efficient markov chain monte carlo algorithm is designed for model estimation we find evidence of stickiness of ratings and of the three sources of ratings persistence with the true state dependence being weak

precautionary saving and accidental bequests this paper presents a simple general equilibrium model of precautionary saving and accidental bequests this model is used to analyze the implications of individual lifetime uncertainty for aggregate consumption and capital accumulation a precautionary demand for saving arises because an individual consumer does not know in advance the date at which he will die and he wants to avoid low levels of consumption in the event that he lives longer than expected an implication of this precautionary saving is that when death does occur the consumer is generally holding some wealth which is then passed on to his heirs in the form of an accidental bequest even if all consumers have the same ex ante mortality probabilities there will be some intracohort variation in the date of death consequently there will be a nondegenerate distribution of bequests left by consumers in a cohort this nondegenerate distribution of bequests left by one generation induces variation in the distributions of wealth consumption and bequests of subsequent generations the importance of bequests in aggregate saving has been established by laurence kotlikoff and lawrence summers 1981 who reported that 80 percent of u s household wealth is inherited wealth one interpretation of this finding is that the simple life cycle model without bequest motives is an inadequate description of saving behavior in the united states but the model i present demonstrates that accidental bequests by selfish consumers can account for a potentially sizeable fraction of aggregate wealth although some part of bequests especially by the wealthy undoubtedly results from an explicit bequest motive accidental bequests also play a role in the intergenerational transfer of wealth as well as in the intragenerational variation in wealth in order to focus on the role of accidental bequests i purposely exclude a bequest motive from the specification of the utility function the effects of lifetime uncertainty on individual consumption behavior were first examined formally in a seminal paper by menachem yaari 1965 yaari s model provided the basic framework for virtually all subsequent work on uncertain lifetimes including well known papers by nils hakansson 1969 stanley fischer 1973 robert barro and james friedman 1977 david levhari and leonard mirman 1977 and kotlikoff and avia spivak 1981 however all of these papers focused on the consumption decision of an individual and ignored the effect of accidental bequests on the behavior of the recipients of these accidental bequests 2 as will be shown at various points in this paper changes in the economic environment can have effects on aggregate behavior which differ sharply from the effects on individual behavior because of the endogenous adjustment of bequests the effects of department of economics harvard university cambridge ma 02138 this paper is a revised version of bequests and social security with uncertain lifetimes nber working paper no 1372 june 1984 i thank olivier blanchard john burbidge christopher cavanagh robert clower stanley fischer benjamin friedman elhanan helpman mervyn king nobuhiro kiyotaki laurence kotlikoff robert mcdonald james pesando julio rotemberg lawrence summers lars svensson mark watson and jeffrey wolcowitz for valuable conversations and correspondence i also thank the participants in seminars at boston university columbia university cornell university federal reserve board harvard university university of iowa mit university of minnesota university of montreal national bureau of economic research north carolina state university the wharton school and yale university and two anonymous referees for their helpful comments i also thank the national science foundation for financial support 1 in the presence of perfect annuity and life insurance markets there may or may not be bequests depending on the presence or absence of a bequest motive but there would be no accidental bequests 2 kotlikoff and spivak focus on the role of the family in providing an incomplete annuities market but stop short of a full scale overlapping generations model in which the distribution of bequests is determined endogenously

designing more efficient markets lessons from los angeles smog control market based approaches for environmental protection are beginning to take root around the world this article attempts to improve our understanding of the performance of environmental markets by constructing and evaluating an information base on trades in los angeles which includes the first detailed data on trading prices the analysis suggests that trading activity has been shaped by the detailed regulations governing the market in addition transaction costs have played a crucial role we argue that the move toward adopting market based approaches for environmental protection needs to be accompanied by a vigorous effort to assess the properties of these systems as they are actually implemented

a framework for estimating dynamic unobserved effects panel data models with possible feedback to future explanatory variables abstract i show how to construct the likelihood function for the conditional maximum likelihood estimator in dynamic unobserved effects models where not all conditioning variables are strictly exogenous the method for handling the initial conditions problem appears to be novel and offers a flexible relatively simple alternative to existing methods

tradeable permits for pollution control when emission location matters what have we learned our knowledge about tradeable permit approaches to pollution control has grown rapidly in the two decades in which they have received serious analytical attention not only have the theoretical models become more focused and the empirical work more detailed but we have now had over a decade of experience with them in the u s this article draws upon economic theory empirical studies and actual experience with implementation to summarize what we have learned about applying tradeable permits to air pollution control in the special circumstance where the spatial aspects of the problem are a prime consideration