dynamic adverse selection a theory of illiquidity fire sales and flight to quality we develop a dynamic equilibrium model of asset markets with adverse selection there exists a unique equilibrium in which better quality assets trade at higher prices but with a lower price dividend ratio in less liquid markets sellers of high quality assets signal quality by accepting a lower trading probability we show how the distribution of sellers private information affects an asset s price and liquidity how a change in that distribution can cause a re sale and a ight to quality and how asset purchase and subsidy programs may raise prices and liquidity and reverse the ight to quality jel d82 g12 this paper develops a dynamic equilibrium model of asset markets with adverse selection the owners of heterogeneous assets are privately informed about the quality of their assets sellers set prices for their assets recognizing that sales may be rationed at high prices buyers set prices recognizing that the quality of available assets may depend on the price selected in equilibrium sellers of high quality assets are willing to set a high price despite the low sale probability because the continuation value from failing to sell a high quality asset is high conversely sellers of low quality assets opt for a low price buyers are indifferent between paying a low price for a low quality asset and a high price for a high quality asset we prove these results in a deliberately stylized dynamic general equilibrium framework assets are perfectly durable and pay a constant dividend each period some amount of a perfectly perishable consumption good better quality assets pay a higher dividend but only the asset s current owner observes the dividend this is the source of private information and the root of the adverse selection problem as in akerlof 1970 the only permissible trades are between the consumption good and the asset individuals are risk neutral and have a discount factor that changes over time independently across individuals creating gains from trade finally discount factors are observable which ensures that patient individuals never sell assets since there are no gains from trade we believe this framework is useful for capturing

efficiency of job creation in a search and matching model with labor force participation in a search and matching model where workers are ex ante heterogeneous with respect to productivity and there is labor force participation albrecht et al 2010 show that satisfying the hosios rule leads to excessive vacancy creation we show that efficient vacancy creation requires a modified version of the hosios condition that captures not only the standard search externalities but also the output externality and the participation externality

efficiency in a search and matching economy with a competitive informal sector we consider a dual labor market with a frictional formal sector and a competitive informal sector we show that the size of the informal sector is generally too large compared to the optimal allocation of the workers it follows that our results give a rationale to informality reducing policies

on the efficiency of participation with vertically differentiated workers in this journal albrecht et al 2010 assume that the planner problem is constrained by participation decisions when this constraint is relaxed participation is too high whereas market tightness is too low subsidizing non participants improves market efficiency and reduces unemployment

auctions with contingent payments there now exists a host of results concerning the revenue performance of various auction methods this note delves deeper into auction markets by examining the effects on sellers revenue of certain noncash means of payment the basic result that bidding mediums which include some contingent pricing feature generally yield the seller more revenue than do cash bids is intriguing by itself and also points out the limitations of received theory since what follows builds on the independent preferences framework it is useful to first note the assumptions of that model and the major results pertaining to it to model an auction in the independent preferences tradition one assumes that bidders have reservation values vi that are known only privately and that can be depicted as being drawn independently from some distribution f v the most important result for this model is the revenue equivalence theorem as given in john riley and william samuelson 1981 any auction involving risk neutral bidders for which the following four conditions hold a a buyer can make any bid above some minimum reserve price b the buyer making the highest bid is awarded the object c the auction rules are anonymous and d there is a common equilibrium bidding strategy in which each buyer makes a bid bi which is a strictly increasing function of his reservation value vi yields an expected revenue of

life cycle equilibrium unemployment this paper extends the job creation job destruction approach to the labor market to take into account a deterministic finite horizon as hirings and separations depend on the time over which investment costs can be recouped the life cycle setting implies age differentiated labor market flows while search by the unemployed falls with age the separation rate is rather u shaped over the life cycle worker heterogeneity in the context of undirected search implies an intergenerational externality which is not eliminated by the hosios condition we show that age specific policies are required to attain the first best allocation

estimating markups and market conduct with multidimensional product attributes we demonstrate how to estimate a model of oligopoly pricing when products are multi dimensionally differentiated we provide an empirical counterpart to recent theoretical work on product differentiation using specifications informed by economic theory we estimate price cost margins for products differentiated in many dimensions

participation recruitment selection and the minimum wage this paper reexamines the efficiency of participation with heterogeneous workers in a search matching model with bargained wages and free entry assuming that firms hire their best applicants we state that participation is insufficient whatever workers bargaining strengths the reason for this is that when holding a job the marginal participant should receive the entire output as a consequence introducing a small minimum wage raises participation job creation and employment therefore the aggregate income of the economy is enhanced

platform competition in two sided markets many if not most markets with network externalities are two sided to succeed platforms in industries such as software portals and media payment systems and the internet must get both sides of the market on board accordingly platforms devote much attention to their business model that is to how they court each side while making money overall this paper builds a model of platform competition with two sided markets it unveils the determinants of price allocation and end user surplus for different governance structures profit maximizing platforms and not for profit joint undertakings and compares the outcomes with those under an integrated monopolist and a ramsey planner jel l5 l82 l86 l96

competitive search equilibrium in this paper i construct an equilibrium for markets with frictions which is competitive in the sense that all agents are price takers and maximize utility subject to a set of market parameters i show that the equilibrium allocation is socially optimal i also show how the competitive search equilibrium can be achieved if employers with vacancies can advertise publicly the wages they pay

unravelling of dynamic sorting we consider a two sided finite horizon search and matching model with heterogeneous types and complementarity between types the quality of the pool of potential partners deteriorates as agents who have found mutually agreeable matches exit the market when search is costless and all agents participate in each matching round the market performs a sorting function in that high types of agents have multiple chances to match with their peers however this sorting function is lost if agents incur an arbitrarily small cost in order to participate in each round with a sufficiently rich type space the market unravels as almost all agents rush to participate in the first round and match and exit with anyone they meet copyright 2005 wiley blackwell

job search and mobility in developing countries theory and policy implications abstract a labor market model is developed in which the formal sector is characterized by search frictions whereas the informal sector is competitive we show that there exists a unique steady state equilibrium in this dual economy we then consider different policies financed by a tax on firms profits we find that reducing the unemployment benefit or the firms entry cost in the formal sector induces higher job creation and formal employment reduces the size of the informal sector but has an ambiguous effect on wages we also find that an employment wage subsidy policy and a hiring subsidy policy have different implications in particular the former increases the size of the informal sector while the latter decreases it

good jobs versus bad jobs this article develops a model of noncompetitive labor markets in which high wage good and low wage bad jobs coexist minimum wages and unemployment benefits shift the composition of employment toward high wage jobs because the composition of jobs in the laissez faire equilibrium is inefficiently biased toward low wage jobs these labor market regulations increase average labor productivity and may improve welfare

managerial incentives on the near linearity of optimal compensation contracts are examined when outcomes depend on managers choices as well as efforts as the cost of effort shrinks relative to payoffs the optimal contract converges to a linear payoff if the control space of the agent has full dimensionality but not otherwise thus when the agent can trade expected return for greater correlation with other returns it is better to ignore relative performance when the cost of effort is small when the choices include all fair gambles and hedges the linear schedule is no more expensive than any other schedule that induces effort unfair gambles are examined as well

estimating network effects in two sided markets without data on prices and quantities abstract i develop a semi structural approach to identify network effects on two sided monopoly platforms without data on prices and quantities when total revenue data is available the test is sufficient when separate revenue data is available on the two sides the test is both necessary and sufficient

sorting and decentralized price competition we investigate the role of search frictions in markets with price competition and how it leads to sorting of heterogeneous agents there are two aspects of value creation the match value when two agents actually trade and the probability of trading governed by the search technology we show that positive assortative matching obtains when complementarities in the former outweigh complementarities in the latter this happens if and only if the match value function is root supermodular that is its nth root is supermodular where n reflects the elasticity of substitution of the search technology this condition is weaker than the condition required for positive assortative matching in markets with random search

non adherence to a low fat diet an economic perspective abstract despite bearing increased risk of suffering a heart attack failure to adhere to a low fat dietary regimen is wide spread the paper applies an expected utility maximization model to inquire into the individual s decision to deviate from a prescribed low fat diet offering an economic explanation for excess high fat consumption the implications of self protection against the risk of dying from an attack are further examined the analysis reveals that self protection and dietary adherence can be complements suggesting that public health policy may help reduce both the risk of an attack and the risk of dying from an attack through providing incentives for self protection

robustness and linear contracts abstract we consider a moral hazard problem where the principal is uncertain as to what the agent can and cannot do she knows some actions available to the agent but other unknown actions may also exist the principal demands robustness evaluating possible contracts by their worst case performance over unknown actions the agent might potentially take the model assumes risk neutrality and limited liability and no other functional form assumptions very generally the optimal contract is linear the model thus offers a new explanation for linear contracts in practice it also introduces a flexible modeling approach for moral hazard under nonquantifiable uncertainty jel d81 d82 d86

a theory of rational addiction we develop a theory of rational addiction in which rationality means a consistent plan to maximize utility over time strong addiction to a good requires a big effect of past consumption of the good on current consumption such powerful complementarities cause some steady states to be unstable they are an important part of our analysis because even small deviations from the consumption at an unstable steady state can lead to large cumulative rises over time in addictive consumption or to rapid falls in consumption to abstention our theory also implies that cold turkey is used to end strong addictions that addicts often go on binges that addicts respond more to permanent than to temporary changes in prices of addictive goods and that anxiety and tensions can precipitate an addiction

risk sharing vs incentives contract design under two sided heterogeneity we study the matching patterns between heterogeneous principals and agents in a principal agent model the resulting equilibrium relationship between risk and incentives could be negative positive or u shaped these results may provide an explanation for the absence of systematic empirical support for the standard risk model d 2005 elsevier b v all rights reserved

estimating market power in a two sided market the case of newspapers the newspaper industry is a two sided market the readers market and the advertising market are closely linked by inter market network externalities we estimate market power in the italian newspaper industry by building a structural model which encompasses a demand estimation

competition between networks a study of the market for yellow pages this paper estimates the importance of network effects in the market for yellow pages i estimate three simultaneous equations consumer demand for usage of a directory advertiser demand for advertising and a publisher s first order condition derived from profit maximizing behaviour estimation shows that advertisers value consumer usage and that consumers value advertising implying a network effect i find that internalizing network effects would significantly increase surplus as an application i consider whether the market benefits from monopoly which takes advantage of network effects or oligopoly which reduces market power i find that a more competitive market is preferable copyright 2004 wiley blackwell

negative assortative matching of risk averse agents with transferable expected utility abstract i give necessary and sufficient conditions for expected utility to be transferable among agents with different state independent risk preferences who share a risk they cannot influence in an assignment game where participants choose partners based on risk aversion the conditions permit a simple proof that matching is negative assortative

marriage and class here we consider a matching model where agents are heterogeneous and utilities nontransferable we utilize this framework to study how equilibrium sorting takes place in marriage markets we impose conditions that guarantee the existence of a steady state equilibrium and then characterize it several examples are developed to illustrate the richness of equilibria the model reveals an interesting sorting externality that can support multiple steady state equilibria even with constant returns to matching excerpt

frictional assignment i efficiency abstract this paper examines the two sided matching problem where the agents on each side of the market are heterogeneous and the matching process is time consuming this is cast in a labor market setting where workers of different skills match with different machine qualities i characterize the efficient allocation and then show that it can be decentralized by a market mechanism the efficient assignment is not always positively assortative despite the fact that machine qualities and skills are complementary in production to decentralize the efficient allocation the market mechanism requires the firms to post wages and commit each machine quality to a particular skill implications on wage inequality are briefly examined journal of economic literature classification numbers j31 e24 j64

efficiency in a search and matching model with participation policy this note presents a random search and matching model with ex ante heterogeneity in worker productivity a social planner with the power to prevent labor market participation by the least productive is shown to increase economic efficiency this is true even at the hosios rule which under worker homogeneity implements the constrained efficient allocation

on the segmentation of markets this paper endogenizes the market structure of an economy with heterogeneous agents who want to form bilateral matches in the presence of search frictions and when utility is nontransferable there exist infinitely many marketplaces and each agent chooses which marketplace to be in agents get to choose not only whom to match with but also whom they meet with perfect segmentation is obtained in equilibrium where agents match with the first person they meet all equilibria have the same matching pattern although perfect assortative matching is not obtained in equilibrium the degree of assortativeness is greater than in standard models

competition and collusion in the american automobile industry the 1955 price war movements in total quantity and in quality adjusted price suggest a supply side shock in the american automobile market in 1955 this paper tests the hypothesis that the shock was a transitory change in industry conduct a price war the key ingredients of the test are alternative equilibrium models of oligopoly under product differentiation in nonnested cox tests of hypotheses a collusive solution is sustained in 1954 and in 1956 while a competitive solution holds in 1955 the result does not appear to be an artifact since it is robust in tests against alternative specifications copyright 1987 by blackwell publishing ltd

matching with noise and the acceptance curse abstract this paper explores matching with both search and information frictions specifically everyone observes only a noisy signal of the true type of any potential mate in this context matching decisions must incorporate not only information about a partner s attribute conveyed by the noisy signal but also as in the winner s curse in auction theory information about a partner s type contained in his or her acceptance decision we show that there exists an equilibrium exhibiting a stochastic positive assorting of types generalizing becker j polit economy 81 1973 813 846 in equilibrium selection is adverse being accepted reduces an agent s estimate of a potential partner s type a phenomenon that we call the acceptance curse effect

on the inefficiency of matching models of unemployment with heterogeneous workers and jobs when firms rank their applicants in a circular matching model with bargained wages firms rank their applicants and pick the most suitable one job creation appears to lower the average output as firms do not internalize this effect there are too many jobs in a laissez faire equilibrium under the hosios condition by contrast job rejection is efficient for the equilibrium value of market tightness consequently introducing unemployment compensation raises the aggregate income by lowering market tightness due to the isomorphism between the two models these results extend to match specific productivities however competitive search restores market efficiency

partnerships versus corporations moral hazard sorting and ownership structure team production takes advantage of technological complementarities but comes with the cost of free ridership when workers differ in skills the choice of sorting pattern may be associated with a nontrivial trade off between exploiting the technological complementarities and minimizing the cost of free ridership this paper demonstrates that whether such a trade off arises depends i on how the power of incentives required for effort provision varies with workers types and ii on whether the workers are organized for production in partnerships or in corporations these results have implications for how production is organized in different industries in partnerships or in corporations jel d21 d82 g32 m12 m54 production in self managed teams and use of group incentives within corporations have become increasingly widespread over the last few decades e g see osterman 2000 and references therein increased reliance on group production can be attributed to the presence of technological complementarities between workers skills this in turn has implications for sorting of workers of different skills into teams namely expected output is maximized when high skilled workers are teamed with other high skilled workers at the same time team production comes with the problem of free riding recent studies such as franco mitchell and vereshchagina 2011 and kaya and vereshchagina 2013 have pointed out that the cost of alleviating this free rider problem may depend on how workers of different skills are sorted into teams therefore the sorting of workers may impact the total surplus from team production in at least two ways by taking advantage of technological complementarities and or by minimizing the cost of alleviating the freerider problem in this paper we illustrate that a nontrivial trade off between these two forces may arise and that this trade off has implications for how production is organized in partnerships or in corporations for this purpose we develop a model of joint production with two sided moral hazard in which workers of heterogeneous productivity may organize in partnerships or work for a corporation owned by an entrepreneur the technology available to

inefficient sorting under output sharing abstract i study sorting in a frictional market asset owners post their terms then workers direct their search when the owners switch from prices to shares the competition between workers is handicapped the unique equilibrium features inefficient positive assortative matching the queue lengths are distorted even though the hosios efficiency condition holds for every pair of types for any distribution of types all workers pair up with better assets the best workers suffer while the weakest workers gain the opposite occurs on the asset side competition drives the asset owners to post flatter contracts it leads to constrained efficiency whenever prices are feasible otherwise handicapped competition results in inefficient sorting

efficiency in a search and matching model with endogenous participation abstract we show that in a search matching model with endogenous participation in which workers are heterogeneous with respect to market productivity satisfying the hosios rule leads to excessive vacancy creation

unemployment insurance in theory and practice a hallmark of modern labor economics is the close interplay between the development of theory data sources and econometric testing the evolution of the economic analysis of unemployment insurance provides a good illustration new theoretical approaches in particular job search theory have inspired a large amount of empirical research some of it methodologically innovative and most of it highly relevant for economic policy the paper presents a broad survey and an assessment of the economic analysis of unemployment insurance as it has evolved since the 1970s

two sided markets a progress report the paper provides a road map to the burgeoning literature on two sided markets and presents new results it identifies two sided markets with markets in which the structure and not only the level of prices charged by platforms matters the failure of the coase theorem is necessary but not sufficient for two sidedness the paper builds a model integrating usage and membership externalities that unifies two hitherto disparate strands of the literature emphasizing either form of externality and obtains new results on the mix of membership and usage charges when price setting or bargaining determine payments between end users

what makes you grab low carb beers what makes people choose low carbohydrate high protein food low carb food which is good for health but usually tastes bad using panel data on us beer consumption in which each consumption occasion is uniquely associated with various companion based consumption contexts and exposure levels to diet information we analyse the variations in consumers preferences for low carb food the results show that there exist considerable gender differences in the preference variation under peer pressure first single females behave in a way they dislike drinking low carb beer in front of friends spouses and significant others second male both married and single and married females pretend to choose low carb beer when accompanied by spouses or significant others finally the elasticity of demand for healthy food with respect to news articles about low carb diets is positive yet with substantial differences in the degree of elasticity across demographic groups

the assignment of workers to jobs in an economy with coordination frictions this paper studies the assignment of heterogeneous workers to heterogeneous jobs owing to the anonymity of a large labor market workers use mixed strategies when applying for jobs this randomness generates coordination frictions two workers may apply for a particular job whereas an identical job gets no applications the model generates assortative matching with a positive but imperfect correlation between matched workers and firms types it predicts that a worker s wage is increasing in her job s productivity and a firm s profit is increasing in its employees productivity the model also yields a version of the welfare theorems

dynamic epidemiology and the market for vaccinations abstract the intent of this paper is to raise the question of how and when externalities can arise in the market for vaccinations static and dynamic models of such markets are developed and compared a special case in a continuous time dynamic framework is examined and is found to be efficient i e there is no externality this is in contrast to the results from the static formulation raising doubts about the suitability of a static approach these results indicate that the question of whether there are externalities in individual immunization decisions is more involved than is generally supposed

performance pay and wage inequality an increasing fraction of jobs in the u s labor market explicitly pay workers for their performance using bonus pay commissions or piece rate contracts using data from the panel study of income dynamics we show that compensation in performance pay jobs is more closely tied to both observed and unobserved productive characteristics of workers than compensation in non performance pay jobs we also find that the return to these productive characteristics increased faster over time in performance pay than in non performance pay jobs we show that this finding is consistent with the view that underlying changes in returns to skill due for instance to technological change induce more firms to offer performance pay contracts and result in more wage inequality among workers who are paid for performance thus performance pay provides a channel through which underlying changes in returns to skill get translated into higher wage inequality we conclude that this channel accounts for 21 of the growth in the variance of male wages between the late 1970s and the early 1990s and for most of the increase in wage inequality above the eightieth percentile over the same period

the effects of labour market policies in an economy with an informal sector in this article we build an equilibrium search and matching model of an economy with an informal sector our model extends mortensen and pissarides 1994 by allowing for ex ante worker heterogeneity with respect to formal sector productivity we use the model to analyse the effects of labour market policy on informal sector and formal sector output on the division of the workforce into unemployment informal sector employment and formal sector employment and on wages finally we examine the distributional implications of labour market policy specifically we analyse how labour market policy affects the distributions of wages and productivities across formal sector matches in this article we construct a search and matching model that we use to analyse the effects of labour market policies in an economy with a significant informal sector what we mean by an informal sector is a sector that is unregulated and hence not directly affected by labour market policies such as severance or payroll taxes we find that labour market policies that apply only to the formal sector nonetheless affect the size and the composition of employment in the informal sector this is important since there is substantial economic activity in the informal sector in many economies particularly in developing countries estimates for some latin american countries put the informal sector at more than 50 of the urban work force 1 the informal sector is also important in many transition countries as well as in some developed economies 2 although much of the literature treats the informal sector as a disadvantaged sector in a segmented labour market framework this interpretation is not consistent with recent empirical evidence from latin america under a segmented or dual labour market interpretation one would expect jobs to be rationed in the primary sector and workers to be in the secondary or informal sector involuntarily and to be queuing for formal sector jobs maloney 2004 presents evidence for several latin american countries that challenges this view and instead interprets the informal sector as an unregulated micro entrepreneurial sector similarly using data from the argentinian household survey pratap and quintin 2006 reject the notion that labour markets are segmented in the greater buenos aires area concluding that there is no evidence of a formal sector wage premium after controlling for individual and establishment we thank mauricio santamaria for stimulating conversations that inspired our interest in this topic we also thank bob hussey and fabien postel vinay as well as our editor steve pischke and two anonymous

age dependent employment protection this paper examines the age related design of firing taxes by extending the theory of job creation and job destruction to account for a finite working life time we first argue that the potential employment gains related to employment protection are high for older workers as they are magnified by the proximity to retirement but higher firing taxes for these workers increase job destruction rates for the younger generations furthermore from a normative standpoint when firms cannot ex ante age direct their search the impact of each generation of unemployed workers on the average return on vacancies makes the internalization of the search costs for the other generations imperfect through the ex post nash bargaining process we show that the first best age profile of firing taxes is typically hump shaped partially in contradiction with existing policies in some european countries taking into account the fact that the human capital of older workers is more specific than general tends to exacerbate these results

quantifying equilibrium network externalities in the ach banking industry we seek to estimate the causes and magnitudes of network externalities for the automated clearinghouse ach electronic payments system using a panel data set on individual bank usage of ach we construct an equilibrium model of consumer and bank adoption of ach in the presence of a network the model identifies network externalities from correlations of changes in usage levels for banks within a network from changes in usage following changes in market concentration or sizes of competitors and from adoption decisions of banks outside the network with small branches in the network and can separately identify consumer and bank network effects we structurally estimate the parameters of the model by matching equilibrium behavior to the data using simulated maximum likelihood and a data set of localized networks and use a bootstrap to recover confidence intervals the parameters are estimated with high precision and fit various moments of the data reasonably well we find that most of the impediment to ach adoption is due to large consumer fixed costs of adoption the deadweight loss from the network externality is moderate the optimal number of ach transactions is about 16 higher than the equilibrium level

workforce location and equilibrium unemployment in a duocentric economy with matching frictions this article examines unemployment disparities and efficiency in a duocentric city where workers are non uniformly distributed between the two job centers we introduce commuting costs and search matching frictions to deal with the spatial mismatch between workers and firms in a decentralized economy job seekers do not internalize a composition externality they impose on all the unemployed with symmetric job centers a change in the distribution of the workforce can lead to asymmetric equilibrium outcomes we calibrate the model for los angeles and chicago metropolitan statistical areas simulations suggest that changes in the workforce distribution have non negligible effects on unemployment rates wages and net output but cannot be the unique explanation of a substantial mismatch problem

junk food home cooking physical activity and obesity the effect of the fat tax and the thin subsidy abstract in an effort to reduce the growing prevalence of obesity a tax on junk foods known as fat tax has been proposed the revenue from which could be used to finance a thin subsidy for healthy foods or exercising equipment the present paper addresses the fat tax and thin subsidy within a food intake rational choice model assuming that healthy meals are cooked at home with purchased ingredients and time input the paper examines the effects on obesity of a tax on junk food meals and a subsidy to cooking ingredients distinguishing between a weight conscious and a non weight conscious individual and between a weight conscious individual who is physically active and physically inactive the results show that for a non weight conscious individual a fat tax will unambiguously reduce obesity whereas a thin subsidy may increase obesity however for a weight conscious individual particularly one who is physically active even a fat tax may increase obesity as it may reduce not just the consumption of junk food but also the time devoted to physical activity the paper explores conditions under which obesity will rise fall or remain intact following the introduction of a fat tax or a thin subsidy

price structure in two sided markets evidence from the magazine industry we present and estimate a model of competition in a two sided market the market for magazine readership and advertising using data on magazines in germany we find evidence that magazines have properties of two sided markets the results are consistent with the perception that prices for readers are subsidized and that magazines make all their money from advertisers consistent with advertisers valuing readers more than readers value advertisements our results imply that higher demand on the reader side increases ad rates but that higher demand on the advertising side decreases cover prices

equilibrium unemployment and retirement we first propose some new empirical evidence on the fact that the labor market conditions matter for the retirement decision at the individual level we investigate whether unemployed workers retire before employed workers other things being equal our main objective in this paper is then to propose an equilibrium unemployment approach to retirement decisions that allows us to derive the positive and normative features of retirement decisions when search and matching frictions are considered two main conclusions emerge the retirement decision of unemployed workers depends on the labor market frictions whereas that of employed workers does not the existence of search externalities makes the retirement age of unemployed workers intrinsically suboptimal considering social security policy issues we show that the complete elimination of the implicit tax on continued activity is not necessarily welfare optimizing in a second best world where the labor market equilibrium suffers from distortions