sequential formation of coalitions in games with externalities and fixed payoff division this paper analyzes a sequential game of coalition formation when the division of the coalitional surplus is fixed and the payoffs are defined relative to the whole coalition structure gains from cooperation are represented by a valuation which maps coalition structures into payoff vectors i show that any core stable coalition structure can be attained as a stationary perfect equilibrium of the game if stationary perfect equilibria may fail to exist in general games a simple condition is provided under which they exist in symmetric games furthermore symmetric stationary perfect equilibria of symmetric games generate a coalition structure which is generically unique up to a permutation of the players a general method for the characterization of equilibria in symmetric games is proposed and applied to the formation of cartels in oligopolies and coalitions in symmetric majority games journal of economic literatureclassification numbers c78 c71 1996 academic press inc

learning and wage dynamics we develop a dynamic model of learning about worker ability in a competitive labor market the model produces three testable implications regarding wage dynamics 1 although the role of schooling in the labor market s inference process declines as performance observations accumulate the estimated effect of schooling on the level of wages is independent of labor market experience 2 timeinvariant variables correlated with ability but unobserved by employers such as certain test scores are increasingly correlated with wages as experience increases and 3 wage residuals are a martingale we present evidence from the nlsy that is broadly consistent with the model s predictions

reprint of marriage and health selection protection and assortative mating abstract using data from the panel study of income dynamics psid and the medical expenditure panel survey meps we analyze the health gap between married and unmarried individuals of working age controlling for observables we find a gap that peaks at 10 points at ages 55 59 years the marriage health gap is similar for men and women if we allow for unobserved heterogeneity in innate health permanent and age dependent potentially correlated with timing and likelihood of marriage we find that the effect of marriage on health disappears below age 40 years while about 5 points difference between married and unmarried individuals remains at older ages 55 59 years this indicates that the observed gap is mainly driven by selection into marriage at younger ages but there might be a protective effect of marriage at older ages exploring the mechanisms behind this result we find that better innate health is associated with a higher probability of marriage and a lower probability of divorce and there is strong assortative mating among couples by innate health we also find that married individuals are more likely to have a healthier behavior compared to unmarried ones finally we find that health insurance is critical for the beneficial effect of marriage

wealth accumulation over the life cycle and precautionary savings this article constructs and simulates a life cycle model of wealth accumulation and estimates the parameters of the utility function the rate of time preference and the coefficient of risk aversion by matching the simulated median wealth profiles with those observed in the panel study of income dynamics and in the survey of consumer finances the estimates imply a low degree of patience and a high degree of risk aversion the results are used to study the importance of precautionary savings in explaining wealth accumulation they imply that wealth accumulation is driven mostly by precautionary motives at the beginning of the life cycle whereas savings for retirement purposes become significant only closer to retirement

portfolio choices of parents and their children as young adults asset accumulation by african american families the portfolio composition decision often is stylized as either a life cycle choice to allocate income to consumption or as a choice along a risk return locus with the locus derived from the underlying market equilibrium of asset returns and prices empirical work on household financial behavior has identified large differences in wealth levels and in portfoliocomposition choices of different demographic groups well beyond income and risk tolerance by far the most striking difference in this literature emerges when the population is subdivided by race for example given the strong performance of the u s equity market in the past decade portfolio choices of stocks have been key to wealth building yet africanamerican families have been less likely to have held stocks as of the mid 1980 s and less likely to have become shareholders over the period 1989 1994 erik hurst et al 1998 this paper attempts to resolve this puzzle by examining cross generational influences on current portfolio composition decisions

a theory of endogenous coalition structures consider an environment with widespread externalities and suppose that bind ing agreements can be written we study coalition formation in such a setting our analysis proceeds by defining on a partition function an extensive form bargaining game we establish the existence of a stationary subgame perfect equilibrium for such a game our main results are concerned with the characterization of equilib rium coalition structures we develop an algorithm that generates under certain conditions an equilibrium coalition structure our characterization results are especially sharp for symmetric partition functions in particular we provide a uniqueness theorem and apply our results to a cournot oligopoly journal of economic literature classification numbers c71 c72 c78 d62 q 1999 academic press

marginal contributions and externalities in the value our concern is the extension of the theory of the shapley value to problems involving externalities using the standard axiom systems behind the shapley value for an arbitrary exogenous coalition structure leads to the identification of bounds on players payos around an externality free value in endogenizing the coalition structure we analyze a two stage process of coalition formation in whose second stage our axiomatic results are applied we find reasons to explain inecient coalition structures and provide sucient conditions for eciency

social security unanticipated benefit increases and the timing of retirement between 1969 and 1972 real u s social security retirement benefits rose by 20 the rise was unanticipated and followed over 15 years of relatively constant real benefits this paper proposes a model of retirement behaviour in which workers respond differently although in a theoretically consistent manner to the anticipated and unanticipated components of the social security benefit they can receive upon retirement the retirement age decision in the presence of unanticipated benefit changes is shown to be a special case of utility maximization under a nonlinear budget constraint the model is estimated using the longitudinal retirement history survey between 1969 and 1973 real social security benefits for u s workers with fixed earnings histories were raised by more than 20 these increases were the first significant increases in social security since the early 1950 s at the same time that retirement benefits were rising the trend toward early retirement among older american men accelerated in the period from 1965 to 1970 the labour force participation rate of men aged 55 to 64 fell 1 6 percentage points from 84x6 to 83 0 but in the five years after 1970 the rate fell an additional 7 4 points to 75 6 the participation rate of men over 65 fell by 1 1 points in the five years after 1965 but by 5 2 points during the mid 1970 s 1 not surprisingly a large share of this labour force decline has been attributed to the effects of the social security increases enacted in 1969 and 1972 the purpose of this paper is to determine the precise effect of the unanticipated benefit increases on the timing of retirement the effect of social security on the age at retirement has been the subject of lively debate in recent years the literature has been reviewed in two recent papers by mitchell and fields 1982 and hurd 1983 who reach nearly opposite conclusions about the lessons that can be drawn from past empirical research mitchell and fields find that no definite judgment can be reached about the effects of social security on retirement while hurd argues that more careful studies have all found a significant and meaningful effect of social security on early retirement certainly the earlier studies by boskin 1977 and boskin and hurd 1978 found very large social security effects with boskin concluding that the social security system has been the major factor in the explosion in earlier retirement boskin 1977 p 1 very recent studies by burkhauser and quinn 1983 burtless and moffitt 1984 diamond and hausman 1984 fields and mitchell 1984 and hausman and wise 1985 have found smaller social security effects however none of them dealt explicitly with the rapid rise in real benefits during the early 1970 s the approach taken in this paper differs significantly from that in the earlier research just cited the proposed econometric model takes full account of the nonlinear relationship between goods consumption and the age at retirement introduced by social security

bargaining and value we present and analyze a model of noncooperative bargaining among n participants applied to situations describable as games in coalitional form this leads to a unified solution theory for such games that has as special cases the shapley value in the transferable utility tu case the nash bargaining solution in the pure bargaining case and the recently introduced maschler owen consistent value in the general nontransferable utility ntu case moreover we show that any variation in a certain class of our bargaining procedure which generates the shapley value in the tu setup must yield the consistent value in the general ntu setup

an empirical model of labor supply in a life cycle setting this paper formulates and estimates a structural intertemporal model of labor supply using theoretical characterizations derived from an economic model of lifetime behavior a two step empirical analysis yields estimates of intertemporal and uncompensated substitution effects which provide the information needed to predict the response of hours of work to life cycle wage growth and shifts in the lifetime wage path

the labor supply response to mismeasured but predictable wage changes most panel data studies of intertemporal labor supply assume classical measurement error recent validation studies refute this assumption in this study i address nonclassical measurement error explicitly i use data on males from the panel study of income dynamics validation study to purge measurement error from the panel study of income dynamics i find a large amount of predictable wage variation in the data even after allowing for measurement error however there is almost no labor supply response to these predictable wage changes therefore failure to control for nonclassical measurement error cannot explain the low estimated labor supply elasticities in other papers

are women more risk averse we find that single women exhibit relatively more risk aversion in financial decision making than single men using u s sample data we examine household holdings of risky assets to determine whether there are gender differences in financial risk taking as wealth increases the proportion of wealth held as risky assets is estimated to increase by a smaller amount for single women than for single men gender differences in financial risk taking are also influenced by age race and number of children greater financial risk aversion may provide an explanation for women s lower levels of wealth compared with men s jel j16 d81 g11

stock market participation and the internet theory indicates that frictions e g information and transaction costs could account for the lower than expected stock market participation rates this paper examines the hypothesis that there has been a fundamental change in participation and links this change to the reduction of these frictions by the advent of the internet using panel data on household participation rates over the past decade the results show computer internet using households raised participation substantially more than non computer using households the increased probability of participation was equivalent to having over 27 000 in additional household income or over two more mean years of education

weakly monotonic solutions for cooperative games abstract the principle of weak monotonicity for cooperative games states that if a game changes so that the worth of the grand coalition and some player s marginal contribution to all coalitions increase or stay the same then this player s payoff should not decrease we investigate the class of values that satisfy efficiency symmetry and weak monotonicity it turns out that this class coincides with the class of egalitarian shapley values thus weak monotonicity reflects the nature of the egalitarian shapley values in the same vein as strong monotonicity reflects the nature of the shapley value an egalitarian shapley value redistributes the shapley payoffs as follows first the shapley payoffs are taxed proportionally at a fixed rate second the total tax revenue is distributed equally among all players

stockholding behavior of u s households evidence from the 1983 1989 survey of consumer finances most households persistently invest in riskless assets but not stocks and may do so because they perceive information required for market participation to be costly relative to expected benefits in a consumption capital asset pricing model ccapm increased risk aversion income risk and lower resources reduce the information expense sufficient to deter stockholding bivariate probit analysis using the 1983 1989 survey of consumer finances shows that households with lower risk aversion higher education and greater wealth who were nonstockholders in 1983 had an increased conditional probability of entering by 1989 whereas 1983 stockholders with lower resources more limited education and greater risk aversion were more likely to be nonstockholders by 1989

the retirement consumption puzzle a marital bargaining approach abstract evidence from several countries reveals a substantial drop in household consumption around the age of retirement that is difficult to explain with life cycle models using food consumption data from more than 550 households from the panel study of income dynamics for the years 1979 1986 and 1989 1992 we find that married couple households decrease their expenditures on both food consumed at home and away from home by about 9 following the retirement of the male household head no significant decrease in consumption is found for single households either in a sample of males or a pooled sample of single males and females these results are consistent with a model of marital bargaining in which wives prefer to save more than their husbands do to support an expected longer retirement period and relative control over household decisions is affected by control over market income the pattern of the consumption decline which is increasing in the age gap between husband and wife lends further support to this interpretation

earnings test non actuarial adjustments and flexible retirement abstract in response to the challenges of increasing longevity many countries have introduced flexibility reforms for their public pension systems a key measure of these reforms is the abolishment of earnings tests it is claimed that these reforms increase labor supply and therefore the financial sustainability of pension systems we build a simulation model to show that abolishing an earnings test may indeed create more labor supply but simultaneously reduce the average claiming age when adjustments remain less than actuarial as is the case in most european pension systems flexibility reforms may therefore worsen rather than improve the sustainability of public pension systems

the effects of sons and daughters on men s labor supply and wages in this paper we estimate the effects of children and the differential effects of sons and daughters on men s labor supply and hourly wage rates the responses to fatherhood of two cohorts of men from the psid sample are examined separately and we use fixed effects estimation to control for unobserved heterogeneity we find that fatherhood significantly increases the hourly wage rates and annual hours of work for men from both cohorts most notably men s labor supply and wage rates increase more in response to the births of sons than to the births of daughters

wealth inequality and intergenerational links previous work has had difficulty generating household saving behaviour that makes the distribution of wealth much more concentrated than that of labour earnings and that makes the richest households hold onto large amounts of wealth even during very old age i construct a quantitative general equilibrium overlapping generations model in which parents and children are linked by accidental and voluntary bequests and by earnings ability i show that voluntary bequests can explain the emergence of large estates while accidental bequests alone cannot and that adding earnings persistence within families increases wealth concentration even more i also show that the introduction of a bequest motive generates lifetime savings profiles more consistent with the data

labor supply and government programs a cross country analysis abstract there are substantial cross country differences in labor supply late in the life cycle age 50 a theory of labor supply and retirement decisions is developed to quantitatively assess the role of social security disability insurance and taxation for understanding differences in labor supply late in the life cycle across european countries and the united states the findings support the view that government policies can go a long way towards accounting for the low labor supply late in the life cycle in the european countries relative to the united states with social security rules accounting for the bulk of these effects

household investment decisions and offspring gender parental accounting numerous behavioural factors have been identified as having an impact on household stockholding decisions given there is both theoretical and empirical evidence to support the premise that offspring gender can influence specific types of parental preferences i test the theory that offspring gender has an effect on parental investment decision making i find that offspring gender does influence household stock market participation specifically i find that having only female offspring can significantly increase the probability of stockholding given stockholding can have large effects on household wealth levels and that family wealth levels affect intergenerational transfers this finding could have important implications for understanding distributional welfare issues

bidding for the surplus a non cooperative approach to the shapley value abstract we propose a simple mechanism to determine how the surplus generated by cooperation is to be shared in zero monotonic environments with transferable utility the mechanism consists of a bidding stage followed by a proposal stage we show that the subgame perfect equilibrium outcomes of this mechanism coincide with the vector of the shapley value payoffs we extend our results to implement the weighted shapley values finally we generalize our mechanism to handle arbitrary transferable utility environments the modified mechanism generates an efficient coalition structure and implements the shapley values of the super additive cover of the environment journal of economic literature classification numbers c71 c72

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

is there a retirement savings puzzle in this paper we ask whether households are saving enough for their retirement we use data on income expenditure and expenditure components to analyse patterns of behaviour at and around the time of retirement for successive date of birth cohorts we compare periods of unemployment to periods of retirement and separate expenditures into categories reflecting work related expenditures basic necessities and other goods we find that income typically falls by more at unemployment than retirement but the reverse is true for expenditure we observe falls in expenditure at retirement for all expenditure categories using a stochastic life cycle model including mortality rates we assess the anticipated impact of retirement on consumption against that of unemployment the inter relationship between goods and leisure explains a large part of the persistent fall in expenditure at retirement we argue that the only way in which the life cycle hypothesis could be reconciled with the remaining unanticipated dip in consumption would be with the systematic arrival of unexpected adverse information at the time of retirement

the effects of marital status and children on savings and portfolio choice this paper investigates the impact of demographic shocks on optimal decisions about saving life insurance and most centrally asset allocation we analyze these choices within the framework of a life cycle model that features exogenous changes in family composition heterogeneity in lifetime income and uninsurable fluctuations in earnings and medical costs our analysis indicates that marital status transitions and children can have important effects on optimal household decisions widowhood induces sharp reductions in the portfolio shares in stock and the impact is largest for women and individuals with children divorce causes men and women to reallocate their portfolios in different directions men choose much riskier allocations while women opt for safer ones children play a fundamental role in the optimal portfolio decisions men with children for example increase their shares in response to divorce by less than half as much as men without children comparing our simulation results with panel data evidence on stockholding from the psid and the hrs we conclude that changes in marital status and children matter empirically as well but not always in the ways that the model predicts

sharing a fish stock when distribution and harvest costs are density dependent we studied cooperative and competitive solutions for managing a trans boundary fish stock that has a stock size dependent distribution and harvesting costs using norwegian spring spawning nss herring clupea harengus as a case study this is among the first studies to investigate the effect of a dynamic distribution in a partition function game framework i e including externalities the special feature of nss herring is that it comes under the sole ownership of norway when the stock size is sufficiently low the three players in our game are differentiated by stock ownership cost per unit effort and stock elasticity of harvest we find that cost asymmetry improves the likelihood of forming a stable grand coalition as harvesting load can be assigned to each fishing zone according to a player s relative cost level and the density of fish a dynamic distribution increases the bargaining power of norway because of her ability to control both the total stock and the stock shares in different zones especially during the stock transition years however the bargaining power of norway may disappear if her cost of harvesting exceeds that of the other players this loss of bargaining power can take on two forms first a dynamic distribution may encourage a minor player to free ride because norway needing a coalition partner to improve her cost effectiveness would be less inclined to retaliate as retaliation hurts her ally as much as the free rider second in a stable grand coalition norway is not guaranteed to receive an allocation of benefit shares in proportion to not to say in excess of her stock ownership at the current stock condition the strategy where norway reduces stock abundance below the level where the stock becomes non migratory is found attractive only if the discounting rate is sufficiently high

reference dependent risk attitudes we use koszegi and rabin s 2006 model of reference dependent utility and an extension of it that applies to decisions with delayed consequences to study preferences over monetary risk because our theory equates the reference point with recent probabilistic beliefs about outcomes it predicts specific ways in which the environment influences attitudes toward modest scale risk it replicates classical prospect theory including the prediction of distaste for insuring losses when exposure to risk is a surprise but implies first order risk aversion when a risk and the possibility of insuring it are anticipated a prior expectation to take on risk decreases aversion to both the anticipated and additional risk for large scale risk the model allows for standard consumption utility to dominate reference dependent gain loss utility generating nearly identical risk aversion across situations

core existence in vertically differentiated markets we prove that a sufficient condition for the core existence in a n firm vertically differentiated market is that the qualities of firms products are equispaced along the quality spectrum this result contributes to see that a fully collusive agreement among firms in such markets is more easily reachable when product qualities are not distributed too asymmetrically along the quality ladder

interpreting aggregate wage growth the role of labor market participation a new and easily implementable framework for the empirical analysis of the relationship between aggregate and individual wages is developed aggregate real wages are shown to contain three important bias terms one associated with the dispersion of individual wages a second deriving from compositional changes in the selected sample of workers and a third reflecting the distribution of working hours their importance for interpreting the path of aggregate wages and of the returns to education for recent experience in britain is highlighted a close correspondence between the estimated biases and the patterns of differences shown by aggregate wages is established

the effects of progressive taxation on labor supply when hours and wages are jointly determined this paper extends a standard intertemporal labor supply model to account for progressive taxation as well as the joint determination of hourly wages and hours worked we show that these two factors can have implications for both estimating labor supply elasticities as well as for using these elasticities in tax analysis failure to account for wage hours ties and progressive taxation may cause the hours response to marginal tax rate changes to be understated by 5 to 30 percent for men

a field study on matching with network externalities we study the effects of network externalities within a protocol for matching faculty to offices in a new building using web and survey data on faculty s attributes and choices we identify the different layers of the social network institutional affiliation coauthorships and friendships we quantify the effects of network externalities on choices and outcomes disentangle the layers of the networks and quantify their relative influence finally we assess the protocol used from a welfare perspective our study suggests the importance and feasibility of accounting for network externalities in assignment problems and evaluates techniques that can be employed to this end jel c78 c93 d62 d85 z13

pension design with a large informal labor market evidence from chile this article investigates the fiscal and welfare trade offs involved in designing a pension system when workers can avoid contributing by working informally using a life cycle model of labor supply and saving decisions i structurally estimate preferences and earnings opportunities in the formal and informal sectors using data on chilean households i find limited support for formal jobs rationing instead mandatory pension contributions significantly encourage informality policy experiments show that chile could lower minimum pension spending by 23 while guaranteeing the same income to retirees if the minimum pension s implicit tax rate was increased to 60

the stochastic shapley value for coalitional games with externalities abstract a long debated but still open question in the game theory literature is that of how to extend the shapley value to coalitional games with externalities while previous work predominantly focused on developing alternative axiomatizations in this article we propose a novel approach which centers around the coalition formation process and the underlying probability distribution from which a suitable axiomatization naturally follows specifically we view coalition formation in games with externalities as a discrete time stochastic process we focus in particular on the chinese restaurant process a well known stochastic process from probability theory we show that reformulating shapley s coalition formation process as the chinese restaurant process yields in games with externalities a unique value with various desirable properties we then generalize this result by proving that all values that satisfy the direct translation of shapley s axioms to games with externalities can be obtained using our approach based on stochastic processes

saving and liquidity constraints this paper is concerned with the theory of saving when consumers are not permitted to borrow and with the ability of such a theory to account for some of the stylized facts of saving behavior the models presented in the paper seem to account for important aspects of reality that are not explained by traditional life cycle models copyright 1991 by the econometric society

household asset allocation offspring education and the sandwich generation abstract this paper finds households with children and elderly dependents the sandwich generation significantly reduce both college savings and stockholding having any elderly dependents decreases the probability of both stockholding and college savings by twice as much as poor personal health hence these results have critical implications as they demonstrate the importance and magnitude of links between the pension system college financial aid and wealth accumulation elderly dependents limiting parental funds for offspring education can decrease offspring long term earnings potential via decreased human capital accumulation furthermore decreased stock holdings can decrease long term wealth accumulation and thus intergenerational wealth transfers

social interaction and stock market participation we propose that stock market participation is influenced by social interaction in our model any given social investor finds the market more attractive when more of his peers participate we test this theory using data from the health and retirement study and find that social households those who interact with their neighbors or attend church are substantially more likely to invest in the market than non social households controlling for wealth race education and risk tolerance moreover consistent with a peer effects story the impact of sociability is stronger in states where stock market participation rates are higher

disability capacity for work and the business cycle an international perspective important policy issues arise from the high and growing number of people claiming disability benefits for reasons of incapacity for work in oecd countries economic conditions play an important part in explaining both the stock of disability benefit claimants and inflows to and outflows from that stock employing a variety of cross country and country specific household panel data sets as well as administrative data we find strong evidence that local variations in unemployment have an important explanatory role for disability benefit receipt with higher total enrolments lower outflows from rolls and often higher inflows into disability rolls in regions and periods of above average unemployment in understanding the nature of the cyclical fluctuations and trends in disability it is important to distinguish between work disability and health disability the former is likely to be influenced by economic conditions and welfare programmes while the latter evolves in a slower fashion with medical technology and demographic changes there is little evidence of health disability being related to the business cycle so cyclical variations are driven by work disability the rise in unemployment due to the current global economic crisis is expected to increase the number of disability insurance claimants

individual and aggregate labor supply in heterogeneous agent economies with intensive and extensive margins we develop a heterogeneous agent general equilibrium model that incorporates both intensive and extensive margins of labor supply a nonconvexity in the mapping between time devoted to work and labor services distinguishes between extensive and intensive margins we consider calibrated versions of this model that dier in the value of a key preference parameter for labor supply and the extent of heterogeneity the model is able to capture the salient features of the empirical distribution of hours worked including how individuals transit within this distribution we then study how the various specications inuence labor supply responses to aggregate technology shocks we nd that abstracting from intensive margin adjustment has large eects on the volatility of aggregate hours even if intensive margin uctuates relatively little

sharing a river among satiable agents abstract we consider the problem of efficiently sharing water from a river among a group of satiable agents since each agent s benefit function exhibits a satiation point the environment can be described as a cooperative game with externalities we show that the downstream incremental distribution is the unique distribution which both is fair according to the aspiration welfare principle and satisfies the non cooperative core lower bounds on the other hand the cooperative core may be empty furthermore the downstream incremental distribution satisfies all core lower bounds for all connected coalitions if and only if each agent s individual rationality constraint is independent of the behavior of the other agents

the effect of social security on labor supply a cohort analysis of the notch generation this article uses aggregate birth year calendar year level data derived from the current population survey cps to estimate the effect of social security wealth on the labor supply of older men in the 1970s and 1980s the analysis focuses on measuring the impact of the 1977 amendments to the social security act which created a substantial unanticipated reduction in social security wealth for individuals born after 1916 this differential in benefits has become known as the benefit notch results indicate that labor supply continued to decline for the notch babies who received lower social security benefits than earlier cohorts

is consumption growth consistent with intertemporal optimization evidence from the consumer expenditure survey in this paper we show that some of the predictions of models of consumer intertemporal optimization are in line with the patterns of nondurable expenditure observed in u s household level data we propose a flexible specification of preferences that allows multiple commodities and yields empirically tractable equations we estimate preference parameters using the only u s micro data set with complete consumption information we show that previous rejections can be explained by the simplifying assumptions made in previous studies we also show that results obtained using good consumption or aggregate data can be misleading

humps and bumps in lifetime consumption in this article we argue that the life cycle model that allows demographics to affect household preferences and relaxes the assumption of certainty equivalence can generate hump shaped consumption profiles over age that are very similar to those observed in household level data sources and in particular match the differences in shape across different education groups liquidity constraints or myopia are not required to explain the empirical features of observed life cycle patterns

a life cycle model of health and retirement the case of swedish pension reform abstract sweden is one of the few western economies to have undertaken a large pension reform in recent years this was done with great expectations but little formal analysis in this paper we develop a life cycle labor supply model to quantify the predicted labor supply implications of this reform in our framework individuals choose when to stop working and given eligibility criteria when if to apply for disability and pension benefits agents are heterogeneous in skills and receive exogenous shocks to health throughout their life we find that the new pension system creates large incentives for the continued employment of older workers this is promising news for countries grappling with pension reform and indicates that there are significant lessons to be learned from the swedish case

bargaining and cooperation in strategic form games in this paper we view bargaining and cooperation as an interaction superimposed on a game in strategic form a multistage bargaining procedure for n players the proposer commitment procedure is presented it is inspired by nash s two player variable threat model a key feature is the commitment to threats we establish links to classical cooperative game theory solutions such as the shapley value in the transferable utility case however we show that even in standard pure exchange economies the traditional coalitional function may not be adequate when utilities are not transferable jel c70 c71 c78 d70

the mortality effects of retirement evidence from social security eligibility at age 62 abstract social security eligibility begins at age 62 and approximately one third of americans immediately claim at that age we examine whether age 62 is associated with a discontinuous change in aggregate mortality a key measure of population health using mortality data that covers the entire u s population and includes exact dates of birth and death we document a robust two percent increase in male mortality immediately after age 62 the change in female mortality is smaller and imprecisely estimated additional analysis suggests that the increase in male mortality is connected to retirement from the labor force and associated lifestyle changes

effects of permanent and transitory tax changes in a life cycle labor supply model with human capital i examine effects of labor income taxation in life cycle models with human capital accumulation in this case the opportunity cost of time equals the wage plus returns to work experience this has several interesting consequences first the data appear consistent with larger labor supply elasticities than prior work suggests second contrary to conventional wisdom permanent tax changes can have larger effects on current labor supply than temporary changes third human capital dampens responses of young workers to transitory tax changes fourth labor supply elasticities increase with age fifth human capital amplifies the effect of permanent tax changes in the long run

social security liquidity and early retirement abstract this paper investigates the effect of social security on retirement decisions it argues that it is important to take realistic account of how recipients evaluate potential benefit flows the paper presents a simple retirement model in which liquidity constraints prompt individuals to use higher than market discount rates in evaluating future pension benefits as a consequence even an apparently actuarially fair early retirement benefit could on average discourage continued work using data on individual retirement decisions i find support for the argument that this phenomenon contributes to some of the observed increase in early retirement

labor force dynamics of older men this paper describes and analyzes movements of older men among labor force states in the united states using quarterly observations derived from the retirement history survey rhs the results indicate substantial undercounts in the biannual data indicating that the prevalence of labor force movements at older ages has been underestimated previously the results show that labor force dynamics at older ages are important including duration and spell occurrence dependence and work experience effects these effects are robust to nonparametric controls for unobserved heterogeneity the estimates indicate that social security benefits have strong effects on the timing of labor force transitions at older ages but that changes in social security benefit levels over time have not contributed much to the trend toward earlier labor force exit excerpt

the effects of health insurance and self insurance on retirement behavior this paper provides an empirical analysis of the effects of employer provided health insurance medicare and social security on retirement behavior using data from the health and retirement study we estimate a dynamic programming model of retirement that accounts for both saving and uncertain medical expenses our results suggest that medicare is important for understanding retirement behavior and that uncertainty and saving are both important for understanding the labor supply responses to medicare half the value placed by a typical worker on his employer provided health insurance is the value of reduced medical expense risk raising the medicare eligibility age from 65 to 67 leads individuals to work an additional 0 074 years over ages 60 69 in comparison eliminating 2 years worth of social security benefits increases years of work by 0 076 years

the effect of part time work on wages evidence from the social security rules this article identifies the part time wage effect using hours variation caused by the social security rules we show that work hours and wages drop sharply at ages 62 and 65 we argue that the hours decline causes the wage decline resulting in a 25 wage penalty for men who cut their work week from 40 to 20 hours however we find little evidence for such an effect among women we also show that models that fail to account for the joint determination of hours and wages will understate the labor supply response to a tax change by about 26

confidence and the real value of money in an overlapping generations economy we demonstrate that stochastic bubbles which have a constant exogenous probability of collapsing may exist in general equilibrium on an intrinsically useless and unbacked asset money this may happen provided that the probability q that the bubble will persist next period is large enough and exceeds a threshold level q which we call the minimum rate of confidence this condition is always violated when the economy without bubble is dynamically efficient it is more likely to be satisfied in dynamically inefficient economies the larger the size of the inefficiency as measured by the excess of the growth rate over the no bubble interest rate we study both exchange and production economies

intertemporal substitution in labor supply evidence from micro data the sensitivity of the supply of labor to intertemporal variation in the wage is an important issue in macroeconomics the analysis of social security and pensions and the study of life cycle patterns of work this paper explores two approaches to the measurement of intertemporal substitution that have appeared in the literature the first approach is to use consumption to control for wealth and unobserved expectations about future wages in the labor supply equation the second approach is to estimate a first difference equation for hours in which labor supply from the previous period serves as a control for wealth and wage expectations the results indicate that intertemporal substitution elasticity for married men is positive but small

endogenous formation of coalitions the formation of coalitions is a fundamental problem in game theory by a coalition is meant a group of players e g economic or political agents which decide to act together as one unit relative to the rest of the players this includes the instances of syndicates unions cartels blocks political parties parliamentary coalitions etc we would like to emphasize that forming a coalition does not eliminate the individual players as decision makers in all interactions with the other players coalition members act as one unit it may be useful to think of a representative agent taking their place 2 however this arrangement will continue only as long as each player finds it desirable to act this way further bargaining occurs among the members of each coalition on how to divide what they obtained together thus the existence of coalitions implies that the interactions among the players will be conducted on two levels first among the coalitions and second within each coalition most of the existing models in economics and game theory assume that the coalition structure is given exogenously instead we try here to obtain it as an endogenous outcome of our model namely we want to be able to predict which coalitions will in fact form in each given situation 3 our theory combines two kinds of game theoretic concepts value and stability the basic idea is first to evaluate the players prospects in the various coalition structures and then based on these values to find which ones are stable we will call this value coalition structure value or cs value for short the reason we are considering coalition structures i e partitions of the set of players into disjoint coalitions rather than just coalitions is that in general players may find it to their advantage to join forces in some situations and to act separately in others all depending on the way the other participants are organized this implies that both the value and the stability concepts should depend on the entire coalition structure the cs value we analyze in this paper was first developed by owen 7

rational bargaining in games with coalitional externalities this paper provides a flexible strategic framework to analyze bargaining and values in environments with coalitional externalities within this framework we propose a new value that extends the shapley value to partition function form games the so called rational belief shapley rbs value we investigate the strategic foundation of the rbs value by constructing an implementation mechanism this mechanism extends existing models of multilateral bargaining by allowing players a higher degree of freedom to form coalitions the same framework of bidding and renegotiation allows for natural variations of the rbs mechanism in this way alternative shapley like values are obtained and a unified platform to analyze and compare these solutions is provided

social security reform and intertemporal smoothing abstract this paper examines the welfare and distributional impact of switching from a defined benefit pension system like social security to a defined contribution system of personal retirement accounts pras while such a switch would do away with the transfers that low wage workers receive through social security it would have the benefit of reducing labor supply distortions moreover a particular kind of pra suggested in this paper one that has very low or zero contribution rates early in life substantially enhances life cycle patterns of consumption and labor supply by making more resources available to credit constrained young workers simulations of a life cycle model show that in welfare terms these pras significantly outperform conventional pras because of this enhanced intertemporal smoothing

on the externality free shapley shubik index abstract we address the problem of extending the shapley shubik index to the class of simple games with externalities introduced in alonso meijide et al 2017 on the one hand we provide bounds for any efficient symmetric and monotonic power index on the other hand we characterize the restriction of the externality free value of de clippel and serrano 2008 to the class of games under study by adapting well known properties

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

why do so few hold stocks the authors investigate why 75 percent of u s households do not hold stocks despite the equity premium and predictions of expected utility models the question is relevant for privatization asset pricing and tax progressivity issues they show that risk aversion per se heterogeneity of beliefs habit persistence time nonseparability and quantity constraints on borrowing do not account for the phenomenon a wedge between borrowing and lending rates and minimum investment requirements are plausible but empirically weak factors more promising explanations are inertia and departures from expected utility maximization there is also qualified support for nondiversifiable income risk as a contributing factor copyright 1995 by royal economic society

children and household economic behavior this paper looks at some of the methodological issues that arise in modeling the effects of children on household behavior and presents some estimates for selected areas for our purposes household behavior will be taken to refer to household decisions on labor supply the allocation of expenditure to different periods and the decision as to what to do with the difference between income and expenditure i shall be concerned mainly with the effects of dependent children and i restrict attention largely to western societies excerpt

how social security and medicare affect retirement behavior in a world of incomplete markets this paper provides an empirical analysis of how the u s social security and medicare insurance system affect the labor supply of older males in the presence of incomplete markets for loans annuities and health insurance we estimate a detailed dynamic programming dp model of the joint labor supply and social security acceptance decision focusing on a sample of males in the low to middle income brackets whose only pension is social security the dp model delivers a rich set of predictions about the dynamics of retirement behavior and comparisons of actual vs predicted behavior show that the dp model is able to account for wide variety of phenomena observed in the data including the pronounced peaks in the distribution of retirement ages at 62 and 65 the ages of early and normal eligibility for social security benefits respectively we identify a significant fraction of health insurance constrained individuals who have no form of retiree health insurance other than medicare and who can only obtain fairly priced private health insurance via their employer s group health plan the combination of significant individual risk aversion and a long tailed pareto distribution of health care expenditures implies that there is a significant security value for these individuals to remain employed until they are eligible for medicare coverage at age 65 overall our model suggests that a number of heretofore puzzling aspects of retirement behavior can be viewed as artifacts of particular details of the social security rules whose incentive effects are especially strong for lower income individuals and those who do not have access to fairly priced loans annuities and health insurance

consumption retirement and social security evaluating the efficiency of reform that encourages longer careers abstract this paper proposes and analyzes a social security reform in which individuals no longer face the oasi payroll tax after say age 54 or a career of 34 years and their subsequent earnings have no bearing on their benefits we first estimate parameters of a life cycle model our specification includes non separable preferences and possible disability it predicts a consumption expenditure change at retirement we use the magnitude of the expenditure change together with households retirement age decisions to identify key structural parameters the estimated magnitude of the change in consumption expenditure depends importantly on the treatment of consumption by adult children of the household simulations indicate that the reform could increase retirement ages one year or more equivalent variations could average more than 4000 per household and income tax revenues per household could increase by more than 14 000

estimating the effect of individual time preferences on the use of disease screening economists have long been interested in evaluating the role that time preferences play in a wide range of economic decisions in the health care arena time preferences may be an especially important determinant of many decisions particularly the use of preventative health care one potential barrier to patient adoption of preventative screening regimens is that they impose current costs on consumers with the hope of lower costs in the future using data from a national survey we jointly estimate latent discount rate and preventative service demand models using a limited information maximum likelihood estimator iterated m estimator the results suggest that discount rates are generally inversely related to the likelihood of most screening tests

trends in male labor force participation and retirement some evidence on the role of pensions and social security in the 1970 s and 1980 s this article estimates the effects of changes in pension plans and social security in the 1970s and 1980s on the steady state retirement of men work incentives associated with pension coverage and plan characteristics are calculated primarily from the 1969 79 retirement history study and the 1983 and 1989 surveys of consumer finances simulations with a structural retirement model suggest that the long run effects of changes in pension plans and social security account for about a quarter of the reduction in full time work by men in their early sixties but cannot explain the reduction by those age 65

precautionary portfolio behavior from a life cycle perspective abstract the literature on household asset accumulation draws a sharp distinction between short run precautionary motives to buffer consumption from annual income shocks and long run life cycle considerations under income certainty however estimates of shock persistence imply considerable career uncertainty we study long run precautionary motives for life cycle wealth accumulation and portfolios allowing for uncertain returns incomes and lifespan we separate the effects of various factors on mean and median asset holdings including education risk aversion household heterogeneity bequests impatience variance and serial correlation of income shocks numerical solutions are compared with data from the 1992 survey of consumer finances

a structural retirement model the life cycle model analyzed here constrains most work on the main job to be full time partial retirement entails a wage reduction and frequently a job change maximum likelihood estimates of utility function parameters are designed to incorporate information on the age of leaving full time work and the age of full retirement the model closely tracks retirement behavior including peaks in retirement activity at 62 and 65 the paper explores the relation of these peaks to nonlinearities in the budget constraint created by various retirement programs policy analyses based on this and on earlier models with simpler structures are compared the retirement choice is one of the more prominent manifestations of life cycle behavior the decision is the result of an interplay between an individual s preferences and a set of incentives which change in complicated ways as the individual progresses through his or her late 50 s and 60 s the purpose of this study is to formulate and estimate a structural model which incorporates in a fundamental way this interplay between lifetime preferences and incentives and to illustrate how such a model may be used to investigate retirement behavior a structural model of this type is essential for analyzing potential policy changes which can be expected to affect incentives in varying ways over a number of years in the life cycle the current study incorporates two structural features which have frequently been omitted from previous studies first the model requires that an individual who wishes to reduce work effort below full time must accept a reduced hourly wage rate in order to do so this reflects empirical evidence from micro data sets which indicates that around one third of older individuals engage in part time work at one time or another and that regardless of whether or not these older workers change jobs to obtain part time work they usually take wage cuts as compared to their previous full time work 2 the fact that an individual is willing to accept a lower wage rate in return for the opportunity to work fewer than full time hours contains important information about the preferences of the

the stability of hedonic coalition structures we consider the partitioning of a society into coalitions in purely hedonic settings i e where each player s payoff is completely determined by the identity of other members of her coalition we first discuss how hedonic and nonhedonic settings differ and some sufficient conditions for the existence of core stable coalition partitions in hedonic settings we then focus on a weaker stability condition individual stability where no player can benefit from moving to another coalition while not hurting the members of that new coalition we show that if coalitions can be ordered according to some characteristic over which players have single peaked preferences or where players have symmetric and additively separable preferences then there exists an individually stable coalition partition examples show that without these conditions individually stable coalition partitions may not exist we also discuss some other stability concepts and the incompatibility of stability with other normative properties journal of economic literature classification numbers c71 a14 d20

efficient bidding with externalities we implement a family of efficient proposals to share benefits generated in environments with externalities these proposals extend the shapley value to games with externalities and are parametrized through the method by which the externalities are averaged we construct two slightly different mechanisms one for environments with negative externalities and the other for positive externalities we show that the subgame perfect equilibrium outcomes of these mechanisms coincide with the sharing proposals

lloyd shapley s matching and game theory this is a survey of lloyd shapley s contributions to matching theory and game theory in general starting with the work that inspired the swedish academy to award the 2012 nobel memorial prize in economic sciences to lloyd shapley and alvin roth

gender bias investments in children and bequests the impacts of pure sex preference and differential earnings opportunities by gender on investments in children are modelled with altruism if bequest constraints do not bind human investments are privately efficient with the higher earning gender receiving more education education does not depend on parental wealth the gender differential in bequests is ambiguous however even in this case when bequest constraints bind education may depend on wealth and it is also possible for the gender with better earnings opportunities to get less education the model is tested with data from philippine villages where bequest constraints are generally nonbinding the schooling differential slightly favors daughters estimated bequest behavior however reflects pure sex preference in terms of our model copyright 1995 by economics department of the university of pennsylvania and the osaka university institute of social and economic research association

labour supply the roles of human capital and the extensive margin we specify and estimate a life cycle labour supply model that expands on earlier work by simultaneously including human capital accumulation saving and bequests an active extensive margin a realistic specification of the progressive tax structure and the social security system and an accounting for private pensions and health expenditures by incorporating all these features we develop new insights into how taxes affect life cycle labour supply for instance we find that labour supply elasticities vary in important ways with age education and the tax structure itself we also show how human capital affects elasticities differently on the intensive versus extensive margins

the effect of age targeted tax credits on labor force participation of older workers abstract i analyze the effect of income tax policy changes on labor force participation of older workers i exploit two age targeted policy initiatives to promote work at older ages simultaneously implemented in sweden in 2007 an earned income tax credit and a payroll tax credit for workers above age 65 using an age based discontinuity in eligibility criteria i conduct a difference in differences analysis with the reform as an instrument for the net of tax rate i find a participation elasticity with respect to the net of participation tax rate of about 0 22 in the year following the 65th birthday for individuals who were working four years earlier

efficiency in coalition games with externalities a natural extension of superadditivity is not sufficient to imply that the grand coalition is efficient when externalities are present we provide a condition analogous to convexity that is sufficient for the grand coalition to be efficient and show that this also implies that the appropriately defined core is nonempty moreover we propose a mechanism which implements the most efficient partition for all coalition formation games and characterizes the resulting payoff division

back to work expectations and realizations of work after retirement this paper analyzes a puzzling aspect of retirement behavior known as unretirement nearly 50 percent of retirees follow a nontraditional retirement path that involves partial retirement or unretirement and at least 26 percent of retirees later unretire i explore two possible explanations 1 unretirement transitions result from failures in planning or financial shocks and 2 unretirement transitions are anticipated prior to retirement reflecting a more complex retirement process i show that unretirement was anticipated for the vast majority of those returning to work and is not a result of financial shocks poor planning or low wealth accumulation

sharing the surplus an extension of the shapley value for environments with externalities economic activities both on the macro and micro level often entail wide spread externalities this in turn leads to disputes regarding the compensation levels to the various parties affected we propose a method of deciding upon the distribution of the gains costs of cooperation in the presence of externalities when forming the grand coalition is efficient we show that any sharing rule satisfying efficiency linearity dummy player and a strong symmetry axioms can be obtained through an average game adding an additional axiom we identify one unique rule satisfying these properties