time orientation and asset prices we analyze a general equilibrium asset pricing model where a small subset of the consumers investors have a short run urge to save that is their attitude toward consumption in the long run is a standard one f they do place zero weight on consumption far enough out in the future f but their short run effective rates of discount may be negative our model which is an elaboration on the framework proposed by faruk gul and wolfgang pesendorfer does not feature time inconsistencies thus we view consumers as fully rational but subject to specific internal frictions in the form of temptation and self control problems the model nests the mehra prescott model and we use it as a way of interpreting the wealth and asset pricing data some aspects of these data we argue can possibly be better understood using our model than the standard one r 2002 published by elsevier science b v

temptation and social security in a dynastic framework abstract we investigate welfare and aggregate implications of a pay as you go payg social security system in a dynastic framework in which individuals have self control problems the presence of self control problems induces individuals to save less because of their urge for temptation towards current consumption individuals efforts to balance between the short term urge for temptation and the long term commitment for consumption smoothing result in self control costs in this environment payg social security works as a self control cost reducing device in contrast the presence of altruism induces individuals to save more this in turn mitigates the adverse effects of self control problems and payg social security on savings but magnifies the self control costs we find that in our environment the adverse welfare effects of a payg system are further mitigated relative to the environments that incorporate altruism and self control issues separately however the level of mitigation is quite modest

time inconsistent preferences and social security revisited in continuous time abstract imrohoroglu et al 2003 prove that it is impossible in a three period partial equilibrium model for social security to improve the welfare of a naive quasi hyperbolic agent if the program has a negative net present value this paper first generalizes their impossibility theorem to a continuous time setting and then proves analytically that no discount function exists that can rationalize a social security program with a negative net present value

the optimal level of social security benefits the optimal level of social security benefits depends on balancing the protection that these benefits offer to those who lack the foresight to provide for their own old age against the welfare costs of distorting economic behavior the primary such cost is the distortion in private saving the present paper derives the level of social security benefits that is optimal in three basic cases in the first section the paper derives the optimal level of benefits for an economy in which all individuals do not anticipate retirement at all and therefore do no saving the second and third sections then derive optimal benefits for two different definitions of incomplete myopia

labor supply and the optimality of social security abstract traditional economic theory predicts that an unfunded public pension system can be justified on the basis of its ability to provide intergenerational transfers and also for its ability to provide partial insurance against mortality and labor income risks in this paper i demonstrate that the quantitative importance of these traditional roles depends on how the pension system distorts households labor supply decisions using a general equilibrium life cycle consumption model calibrated to the u s economy i show that these distortions can be large enough to erase much of the traditional welfare gains from social security i also find that this fact is robust within the range of labor supply elasticities usually encountered in the macroeconomic literature

time inconsistent preferences and social security in this paper we examine the role of social security in an economy populated by overlapping generations of individuals with time inconsistent preferences who face mortality risk individual income risk and borrowing constraints we find that unfunded social security lowers the capital stock output and consumption for consumers with time consistent or time inconsistent preferences however it may raise or lower welfare depending on the strength of time inconsistency

trade environment and development the issues in perspective abstract this special issue on trade and the environment brings together a number of papers that are constructively critical of the conventional economic wisdom on the topic we think that this criticism is warranted because of the decidely uncritical way in which free trade has been advocated in much of the literature and especially in policy the papers analyse the validity of the underlying assumptions on which the conventional wisdom is based and provide suggestions for ways to facilitate trade that is also adequately protective of the environment sustainability and other social values in this introductory piece we discuss trade the environment and sustainability summarizing arguments in the papers included in this issue and adding a few additional points not covered by them

confronting the environmental kuznets curve t he environmental kuznets curve posits an inverted u relationship between pollution and economic development kuznets s name was apparently attached to the curve by grossman and krueger 1993 who noted its resemblance to kuznets s inverted u relationship between income inequality and development in the first stage of industrialization pollution in the environmental kuznets curve world grows rapidly because people are more interested in jobs and income than clean air and water communities are too poor to pay for abatement and environmental regulation is correspondingly weak the balance shifts as income rises leading industrial sectors become cleaner people value the environment more highly and regulatory institutions become more effective along the curve pollution levels off in the middle income range and then falls toward pre industrial levels in wealthy societies the environmental kuznets curve model has elicited conflicting reactions from researchers and policymakers applied econometricians have generally accepted the basic tenets of the model and focused on measuring its parameters their regressions typically fitted to cross sectional observations across countries or regions suggest that air and water pollution increase with development until per capita income reaches a range of 5000 to 8000 when income rises beyond that level pollution starts to decline as shown in the conventional ekc line in figure 1 in developing countries some policymakers have interpreted such results as conveying a message about priorities grow first then clean up numerous critics have challenged the conventional environmental kuznets curve both as a representation of what actually happens in the development process and as a policy prescription some pessimistic critics argue that crosssectional evidence for the environmental kuznets curve is nothing more than a

the cyclical and secular behaviour of the labour input comparing efficiency units and hours worked summary a monthly labour input series designed to correct for the fact that all hours worked are not of the same quality is constructed and its properties compared with unadjusted hours worked this efficiency units series is constructed from bls data on hours worked and earnings by age and sex the cyclical fluctuations displayed by the efficiency units series are smaller on average than those displayed by hours worked although the difference is not large however the secular behaviour of the series is quite different hours worked per capita displays a significant positive trend while efficiency units per capita does not

quasi hyperbolic discounting and retirement abstract some people have self control problems regularly this paper adds endogenous retirement to laibson s quasi hyperbolic discounting savings model quarterly journal of economics 112 1997 443 477 earlier selves think that the deciding self tends to retire too early and may save less to induce later retirement still earlier selves may think the pre retirement self does this too much saving more to induce early retirement the consumption pattern may be different from that with exponential discounting other observational non equivalence includes the impact of changing mandatory retirement rules or work incentives on savings and a possibly negative marginal propensity to consume out of increased future earnings naive agents are briefly considered

after the big bang obstacles to the emergence of the rule of law in post communist societies when russia launched mass privatization it was widely believed that it would create a powerful constituency for the rule of law that didn t happen we present a dynamic equilibrium model of the political demand for the rule of law and show that beneficiaries of mass privatization may fail to demand the rule of law even if it is the pareto efficient rule of the game the reason is that uncertainty about the legal regime can lead to asset stripping and stripping can give agents an interest in prolonging the absence of the rule of law this abstract was borrowed from another version of this item

pollution policy and trade liberalization of environmental goods during the doha round at the world trade organization reductions in trade barriers on environmental goods eg were put forward as a means of helping developed and developing countries alike deal with current environmental problems we examine the potential effectiveness of such a strategy in a developing country that imports all its consumption of eg from an imperfectly competitive foreign eco industry we point out that trade liberalization of eg might in fact lead to less stringent pollution taxes which can result in an actual rise in pollution levels we then show that the environmental effectiveness objective of this trade reform can be achieved when the regulator uses quantitative abatement standards as an alternative pollution policy instrument however this environmental achievement comes at the expense of social welfare

social security and self control preferences abstract we analyze the welfare effects of an unfunded social security system we do so using an overlapping generations economy wherein agents have self control preferences face mortality risk individual income risk and borrowing constraints given our specification of preferences unfunded social security helps reduce the agents temptation to consume in every period consequently the welfare costs it otherwise entails are substantially mitigated while both social security and self control when considered separately reduce welfare their combination renders this effect considerably less severe moreover if the cost of resisting temptation is very high the introduction of social security might even improve welfare

transport and co2 productivity growth and carbon dioxide emissions in the european commercial transport industry in the last decades transport activities persistently increased in the eu27 and were strongly coupled to growth in gross domestic product like most production processes they are inevitably linked with the generation of environmentally hazardous by products such as co2 emissions this leads to the question of how to promote a sustainable transport sector that meets both environmental protection targets and economic requirements in this context the objective of this paper is to compare the co2 sensitve productivity development of the european commercial transport industry for the period between 1995 and 2006 we calculate a malmquist luenberger productivity index to investigate the effects of country specific regulations on productivity and to identify innovative countries our results show a high variation in the co2 sensitive productivity development and a slight productivity decrease on average efficiency losses indicate that the majority of the countries were not able to follow the technological improvements induced by some innovative countries

re evaluating the role of energy efficiency standards a behavioral economics approach abstract the economic models that prescribe pigovian taxation as the first best means of reducing energy related externalities are typically based on the neoclassical model of rational consumer choice yet consumer behavior in markets for energy using durables is generally thought to be far from efficient giving rise to the concept of the energy efficiency gap this paper presents a welfare analysis of energy policies that is based on a behavioral model of temptation and self control introduced by gul and pesendorfer 23 24 we find that in the presence of temptation i pigovian taxes alone do not yield a first best outcome ii when viewed as substitutes energy efficiency standards can dominate pigovian taxes and iii a policy combining standards with a pigovian tax can yield higher social welfare than a pigovian tax alone implying that the two instruments should be viewed as complements rather than substitutes

a welfare analysis of social security in a dynastic framework in this article we study the welfare effects of unfunded social security in a general equilibrium model populated with overlapping generations of altruistic individuals that differ in lifetime expectancy and earnings ability contrary to previous research our results indicate that steady state welfare increases with social security for most households although by very different amounts this result is mainly due to two factors first the presence of two sided altruism significantly mitigates the crowding out effect of unfunded social security second ability shocks and uncertain lifetimes generate significant heterogeneity among households to yield different induced preferences for social security

corruption and development a review of issues in this paper we start with a discussion of some of the different denotations of the problem of corruption we then consider the ways in which the damaging consequences of corruption operate in a developing economy while not ignoring its possible redeeming features in some cases we pursue the question of why corruption is perceptibly so different in different societies and also persistent finally we examine the feasible policy issues that arise in this context

measuring self control problems a structural estimation we perform a structural estimation of the preference parameters in a buffer stock consumption model augmented with temptation disutility we adopt a two stage method of simulated moments methodology to match our simulated moments with those observed in the us survey of consumer finances to identify the parameters we use liquid and quasi liquid retirement wealth holdings at different ages as target moments we find evidence of a significantly positive degree of temptation and estimates under the unrestricted model are more precise than estimates under the restricted model with no temptation overall a model with temptation preferences explains better the observed target moments

equilibrium welfare and government policy with quasi geometric discounting abstract we consider a representative agent equilibrium model where the consumer has quasi geometric discounting and cannot commit to future actions we restrict attention to a parametric class for preferences and technology and solve for time consistent competitive equilibria globally and explicitly we then characterize the welfare properties of competitive equilibria and compare them to that of a planning problem the planner is a consumer representative who without commitment but in a time consistent way maximizes his or her present value utility subject to resource constraints the competitive equilibrium results in strictly higher welfare than the planning problem whenever the discounting is not geometric journal of economic literature classification numbers e21 e61 e91

social security reform with self control preferences abstract this paper analyzes a fully funded social security system under the assumption that agents face temptation issues agents are required to save through individually managed personal security accounts without and with mandatory annuitization when the analysis is restricted to crra preferences our results are congruent with the literature in indicating that the complete elimination of social security is among the reform scenarios that maximize welfare however when self control preferences are introduced and as the intensity of self control becomes progressively more severe the social security elimination scenario loses ground very rapidly in fact in the case of relatively severe temptation the elimination of social security becomes the least desirable alternative under the light of the above findings any reform proposal regarding the social security system should consider departures from standard preferences to preference specifications suitable for dealing with preference reversals

annuities and individual welfare advancing annuity demand theory we present suffcient conditions for the optimality of full annuitization under market completeness that are substantially less restrictive than those used by yaari 1965 we examine demand with market incompleteness finding that positive annuitization remains optimal widely but complete annuitization does not how uninsured medical expenses affect demand for illiquid annuities depends critically on the timing of the risk a new set of calculations with optimal consumption trajectories very different from available annuity income streams still shows a preference for considerable annuitization suggesting that limited annuity purchases are plausibly due to psychological or behavioral biases

consumption savings decisions with quasi geometric discounting we study the consumption savings problem of an infinitely lived rational consumer who has time inconsistent preferences in the form of quasi geometric discounting the consumer operates a weakly concave production function and must simply divide current resources into current consumption and savings there is no uncertainty a solution to the consumer s problem is a subgame perfect equilibrium of a dynamic game between the consumer s successive selves we show that this game has a continuum of equilibria in stationary markov strategies not only is the stationary point of the consumer s asset holdings indeterminate but each stationary point has a continuum of dynamic paths converging to it the savings policy rules underlying these dynamic paths are step functions

re exploring the trade and environment nexus through the diffusion of pollution some scholars argue that trade liberalization results in the outsourcing of pollution to pollution havens and this may explain the existence of the environmental kuznets curve ekc in industrialized countries others claim that trade liberalization effectively lessens pollution by allowing a more efficient use of resources and the diffusion of clean technologies in part because these theories generate similar predictions for industrialized countries empirical studies have not provided conclusive evidence for either argument to identify the role of trade i draw on the insights of the diffusion literature and estimate a spatial regression model where trade operates as the mechanism through which pollution shifts from country to country using the case of per capita carbon dioxide hbox co 2 emissions i find that once spatial correlation is accounted for the ekc disappears the effect is even stronger when looking at trade from developing countries only providing support for the pollution haven hypothesis i also show that the hbox co 2 trajectory of developing countries goes above the one previously followed by industrialized countries this suggests that developing countries carry on an additional carbon burden above the one that would be obtained in the absence of trade these findings contribute to the literature on the non economic effects of trade and the constraints of domestic policies when the costs of trade are low

self control and the theory of consumption to study the behavior of agents who are susceptible to temptation in infinite horizon consumption problems under uncertainty we define and characterize dynamic self control dsc preferences dsc preferences are recursive and separable in economies with dsc agents equilibria exist but may be inefficient in such equilibria steady state consumption is independent of initial endowments and increases in self control increasing the preference for commitment while keeping self control constant increases the equity premium removing nonbinding constraints changes equilibrium allocations and prices debt contracts can be sustained even if the only feasible punishment for default is the termination of the contract

temptation driven behavior and taxation a quantitative analysis in a life cycle model i introduction a central research question in the dynamic fiscal policy literature during the last 30 years or so is whether under fairly general modeling choices the government should impose a positive tax on capital income in the long run the original answer to this question is negative and is due to the seminal papers by chamley 1986 and judd 1985 who established that in the context of a standard neoclassical growth model with infinitely lived individuals an optimal income tax policy entails taxing capital at confiscatory rates in the short run and setting capital income taxes equal to zero in the long run only labor income should be taxed in the long run since then several modeling choices that cast doubt on the validity of this result were identified in the literature imrohoroglu 1998 showed that the optimal capital income tax rate is strictly positive in an overlapping generations olg setting where individuals face idiosyncratic earnings risk borrowing constraints and life span uncertainty conesa kitao and krueger 2009 extended imrohoroglu 1998 by adding a labor leisure choice they demonstrated that the optimal capital income tax rate is equal to 36 and concluded that this high rate is mainly driven by the life cycle structure of the model in contrast krusell kuruscu and smith 2010 analytically showed that within a class of ramsey tax schemes the optimal capital income tax rate should be negative that is savings should be subsidized when agents have self control problems moreover in the special case where consumers succumb completely to temptation ramsey taxes deliver first best welfare outcomes and in contrast to the chamley judd result the optimum calls for a subsidy to savings however an integrated assessment of the combined effects of the relevant trade offs both along the dimension of differences in preferences and along the dimension of the scope of capital income taxation versus labor income taxation is missing from all previous studies in both social security and capital taxation literature and this paper aims to bridge the gap in the literature and contribute in this aspect to the best of our knowledge this paper is the first study that introduces temptation driven preferences in a quantitative model aiming to tackle the question on the optimal capital income tax before proceeding to specifically articulate this paper s contribution to the literature we consider critical to address a question that lies at the very core of our line of research namely why fiscal policy models with time inconsistent or self control preferences are relevant in the first place initially the literature pioneered by strotz 1956 and phelps and poliak 1968 corroborated evidence coming from both introspection and experiments that agents exhibit preference reversals as time passes different strands within this literature have suggested that these preference reversals could be induced by either time inconsistent preferences see laibson 1997 or self control preferences gul and pesendorfer 2004 time inconsistent preferences typically assume that agents have sequences of different selves each valuing consumption streams in a unique way in contrast gul and pesendorfer 2004 provide a dynamically consistent model suitable for addressing preference reversals that does not necessitate splitting up the consumer in multiple selves that is self control preferences these preferences describe an individual that in every period is tempted to consume his entire endowment when he consumes less than his endowment he incurs a disutility cost that stems from exercising self control that is self control cost optimal behavior trades off the temptation to consume vis a vis the long run self interest of the individual 1 alongside these theoretical underpinnings there is sound empirical and experimental evidence that agents suffer from self control problems

the use of patent data for technological forecasting the diffusion of cnc technology in the machine tool industry in the 1980s a dramatic change in the competitive structure of the machine tool industry through the development and implementation of cnc technology occurred for the individual company the timely anticipation and forecast of these technological challenges has been of vital importance in order to incorporate these technological changes into its strategic planning process this paper assesses the suitability of patent data for forecasting technological developments based on the experience in the case of cnc technology following a general description of the technological life cycle concept and the discussion of possible benefits of patent data as a technological forecasting tool actual patenting activity in cnc technology is analysed it is found that the diffusion of cnc technology can be appropriately described by means of patent data different development stages in the life cycle of cnc technology can be distinguished where for each stage strategic r d investment decisions can be derived analysing the impact of cnc technology on the trade pattern between japan and germany clearly reveals that patenting activity causes subsequent and immediate market changes the strong japanese patent position in cnc technology is closely associated with favourable trade changes consequently it is recommended to incorporate the systematic and continuous monitoring of patenting activity into a company s overall competitor monitoring intelligence especially for small and medium sized enterprises patent data analysis provides a technological forecasting instrument with high potential benefits and relatively low cost