moral hazard adverse selection and health expenditures a semiparametric analysis theoretical models predict asymmetric information in health insurance markets may generate inefficient outcomes due to adverse selection and moral hazard however previous empirical research has found it difficult to disentangle adverse selection from moral hazard in health care consumption we propose a two step semiparametric estimation strategy to identify and estimate a canonical model of asymmetric information in health care markets with this method we can estimate a structural model of demand for health care we illustrate this method using a claims level data set with confidential information from a large self insured employer we find significant evidence of moral hazard and adverse selection

a theory of voting equilibria a voting equilibrium arises when the voters in an electorate acting in accordance with both their preferences for the candidates and their perceptions of the relative chances of various pairs of candidates being in contention for victory generate an election result that justifies their perceptions voting equilibria always exist and the set of equilibria can vary substantially with the choice of voting system we compare equilibria under the plurality rule approval voting and the borda system we consider a candidate positioning game and find that the plurality rule imposes little restriction on the position of the winning candidate in three candidate races while approval voting leads to a winner positioned at the median of the voter distribution we contrast campaign activities intended to influence voter preferences with activities meant to influence only perceptions of candidate viability

comment sequential moment restrictions in panel data 1992 comment sequential moment restrictions in panel data journal of business economic statistics vol 10 no 1 pp 20 26

the incidence of medicare abstract the medicare program transfers nearly 300 billion annually from taxpayers to beneficiaries this paper considers the incidence of such transfers in the context of a life cycle model with uncertainty about future health care expenditures we find the distributional consequences of the medicare program are roughly neutral in dollar terms households living in high income neighborhoods pay more in taxes but they also receive more in benefits these dollar flows however ignore the insurance value of the medicare system given the incomplete insurance coverage of lower income elderly households prior to the medicare program the money metric benefits to lower income groups exceed the dollar flows suggesting that medicare redistributes more than a simple accounting exercise would suggest

expanding the life cycle model precautionary saving and public policy one of the key puzzles in understanding saving behavior is not so much why people save the title of this session but why people don t save according to the familiar life cycle model households should accumulate wealth to provide for their retirement consumption the surprising result from the data is the sizable fraction of the population who have accumulated so little even among those nearing retirement given that earnings will almost surely decline when households retire such behavior can imply poor living standards for the elderly some might interpret the low wealth accumulation as being evidence of myopia irrationality or a failure of households to enforce mental accounting richard thaler 1994 while others might view the low level of wealth accumulation as evidence of high individual rates of time preference determining the underlying causes of low wealth is crucial for public policies that seek to alleviate low aggregate saving rates in the united states as well as policies that seek to buttress the adequacy of financial resources for the elderly in this paper we outline what we believe to be the causes of why many people do not save we conclude by speculating about government policies that may be most effective at encouraging saving much of the research examining levels of consumption saving and wealth as well as their responsiveness to policy has been done using a life cycle model with the simplifying assumption of perfect certainty alan auerbach and laurence kotlikoff 1987 for example developed a model with 55 overlapping generations of individual lifecycle households each with empirically plausible age earnings profiles and utility parameters and used the model to address tax policy and demographic issues in a regime in which all households are identical within a generation and all generations know future earnings and interest rates more recently a line of inquiry has examined the effects of uncertainty on saving generally in the context of highly stylized models this research has shown that in these models uninsured earnings uncertainty can alter optimal saving behavior in a variety of important ways for a partial review of this precautionary saving literature see hubbard et al 1994 in two recent papers hubbard et al 1993 1994 we have combined these two strands of the literature by examining the implications of a life cycle model of consumption saving and wealth accumulation subject to what we think are the three most important sources of uninsured idiosyncratic risk facing households uncertainty about earnings medical expenses and length of life our intent has been to create a realistic model in which families live for many periods working for part of their lives and retiring later in life to parameterize the uncertainty facing families we estimate tdiscussants christopher carroll federal reserve board john b shoven stanford university laurence kotlikoff boston university

group decision making in the shadow of disagreement abstract a model of group decision making is studied in which one of two alternatives must be chosen while agents differ in their preferences over alternatives everybody prefers agreement to disagreement our model is distinguished by three features private information regarding valuations differing intensities in preferences and the option to declare neutrality to avoid disagreement there is always an equilibrium in which the majority is more aggressive in pushing its alternative thus enforcing their will via both numbers and voice however under general conditions an aggressive minority equilibrium inevitably makes an appearance provided that the group is large enough such equilibria invariably display a tyranny of the minority the increased aggression of the minority always outweighs their smaller number leading to the minority outcome being implemented with larger probability than the majority alternative we fully characterize the asymptotic behavior of this model as group size becomes large and show that all equilibria must converge to one of three possible limit outcomes

information aggregation rationality and the condorcet jury theorem the condorcet jury theorem states that majorities are more likely than any single individual to select the better of two alternatives when there exists uncertainty about which of the two alternatives is in fact preferred most extant proofs of this theorem implicitly make the behavioral assumption that individuals vote sincerely in the collective decision making a seemingly innocuous assumption given that individuals are taken to possess a common preference for selecting the better alternative however in the model analyzed here we find that sincere behavior by all individuals is not rational even when individuals have such a common preference in particular sincere voting does not constitute a nash equilibrium a satisfactory rational choice foundation for the claim that majorities invariably do better than individuals therefore has yet to be derived

a model of pre electoral coalition formation abstract in many countries three or more candidates compete against one another in single office elections i present a model of three candidates competing for a single office in which two candidates can form a coalition prior to the election a pre electoral coalition since the candidates are both policy and office motivated one candidate can incentivize the other candidate to withdraw his candidacy by choosing a joint policy platform i examine how electoral environments such as election rules ideological distance and pre election polls influence incentives to form pre electoral coalitions i find that pre electoral coalitions are more likely to form i in plurality elections than in two round runoff elections ii as the threshold for first round victory decreases in two round runoff elections iii as the two potential coalition partners ideological distance increases conditional on divided support and iv as the fraction of office value which is transferable increases moreover i analyze and compare voter welfare under plurality and the two round runoff rules

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

lenders on the storm of wholesale funding shocks saved by the central bank abstractwe provide empirical evidence on banks responses to shocks in the wholesale funding market using data of 181 euro area banks over the period from august 2007 to june 2013 responses to funding liquidity shocks for both banks lending volumes and loan rates to households and corporates are analysed in a panel var framework we thereby distinguish banks by country extent of eurosystem borrowing bank size and capitalization the results show that shocks in the securities and interbank markets have significant effects on loan rates and credit supply particularly of banks in stressed countries of the periphery the results also suggest that central bank liquidity has mitigated this effect on lending volumes lending to nonfinancial corporations is more sensitive to wholesale funding shocks than lending to households lending volumes of large banks that are typically more dependent on wholesale funding and banks with large exposure to sovereign bonds show stronger responses to wholesale funding s

the wealth age relation among the aged aged people face the problem of allocating over the rest of their lifetimes the wealth that they have accumulated during their working years this problem is fairly complex because they are uncertain about the dates of their death and because they may wish to use their wealth to finance general consumption or hold it to meet emergencies leave estates or maintain power or status whether skilled at dynamic programming or not aged people effectively do make these decisions what are the results some studies of the entire lifetime pattern of saving and wealth tend to support the simple life cycle model in which the aged use up their wealth to help finance consumption harold lydall for example found saving rates to increase and then decrease with age in the whole population and to be negative for the group aged 65 and over guarded support for the theory was found by franco modigliani and albert ando in britain and by dorothy projector in the united states more recently a f shorrocks examined the lifetime pattern of wealth holding in estate tax data for a single cohort and found the hump pattern that is characteristic of life cycle saving other evidence on wealth holding runs contrary to this however in a study of estate tax returns in washington d c james d smith found that wealth increased with age among the aged after controlling for other demographic variables examining national estate tax data john brittain found wealth to increase with age in the united states and a b atkinson and a j harrison reported the same pattern in england and wales in a sample of tiaa annuity recipients analyzed by james mulanaphy over half reported that their total savings had increased during retirement and another quarter reported that their savings had remained about the same in this paper i examine wealth holding patterns among aged married couples using survey data representing the entire aged population of the united states in 1968 the statistical analysis serves as a test of the hypothesis that emerges from life cycle theory and provides some further exploration into the economic behavior of the aged i find that the aged tend to increase their wealth over time

health insurance and the demand for medical care evidence from a randomized experiment we estimate how cost sharing the portion of the bill the patient pays affects the demand for medical services the data come from a randomized experiment a catastrophic insurance plan reduces expenditures 31 percent relative to zero out of pocket price the price elasticity is approximately 0 2 we reject the hypothesis that less favorable coverage of outpatient services increases total expenditure for example by deterring preventive care or inducing hospitalization

are americans saving optimally for retirement we solve each household s optimal saving decisions using a life cycle model that incorporates uncertain lifetimes uninsurable earnings and medical expenses progressive taxation government transfers and pension and social security benefits with optimal decision rules we compare household by household wealth predictions from the life cycle model using a nationally representative sample we find making use of household specific earnings histories that the model accounts for more than 80 percent of the 1992 cross sectional variation in wealth fewer than 20 percent of households have less wealth than their optimal targets and the wealth deficit of those who are undersaving is generally small

does medicare save lives health insurance characteristics shift at age 65 as most people become eligible for medicare we measure the impacts of these changes on patients who are admitted to hospitals through emergency departments for conditions with similar admission rates on weekdays and weekends the age profiles of admissions and comorbidities for these patients are smooth at age 65 suggesting that the severity of illness is similar on either side of the medicare threshold in contrast the number of procedures performed in hospitals and total list charges exhibit small but statistically significant discontinuities implying that patients over 65 receive more services we estimate a nearly 1 percentage point drop in 7 day mortality for patients at age 65 equivalent to a 20 reduction in deaths for this severely ill patient group the mortality gap persists for at least 9 months after admission

manipulation through political endorsements abstract we study elections with three candidates under plurality voting a candidate is a condorcet loser if the majority of the voters place that candidate at the bottom of their preference rankings we first show that a condorcet loser might win the election in a three way race next we introduce to the model an endorser who has private information about the true probability distribution of the preferences of the voters observable endorsements facilitate coordination among voters who may otherwise split their votes and lead to the victory of the condorcet loser when the endorser has an ideological bias towards one of the candidates the coordination impact of endorsements remains unaltered moreover the endorser successfully manipulates the outcome of the election in favor of his bias even if his ideological bias is known by the voters the results are true for any endorsement cost and any magnitude of bias as long as the electorate is large enough

the oregon health insurance experiment evidence from the first year in 2008 a group of uninsured low income adults in oregon was selected by lottery to be given the chance to apply for medicaid this lottery provides an opportunity to gauge the effects of expanding access to public health insurance on the health care use financial strain and health of low income adults using a randomized controlled design in the year after random assignment the treatment group selected by the lottery was about 25 percentage points more likely to have insurance than the control group that was not selected we find that in this first year the treatment group had substantively and statistically significantly higher health care utilization including primary and preventive care as well as hospitalizations lower out of pocket medical expenditures and medical debt including fewer bills sent to collection and better self reported physical and mental health than the control group

selection on moral hazard in health insurance economic analysis of market failure in insurance markets tends to analyze selection and moral hazard as distinct phenomena in this paper we explore the potential for selection on moral hazard in insurance markets by this we mean the possibility that moral hazard effects are heterogenous across individuals and that individuals selection of insurance coverage is affected by their anticipated behavioral response to coverage we examine these issues empirically in the context of employer provided health insurance in the united states specifically we break down the general

medicaid insurance in old age the old age provisions of the medicaid program were designed to insure retirees against medical expenses we estimate a structural model of savings and medical spending and use it to compute the distribution of lifetime medicaid transfers and medicaid valuations across currently single retirees compensating variation calculations indicate that current retirees value medicaid insurance at more than its actuarial cost but that most would value an expansion of the current medicaid program at less than its cost these findings suggest that for current single retirees the medicaid program may be of the approximately right size

the importance of bequests and life cycle saving in capital accumulation a new answer as the workhorse of consumption and saving research for the past four decades the life cycle model has proved flexible and useful for examining a variety of questions in a classic paper albert ando and franco modigliani 1963 p 56 stated a key assumption of the basic model t he individual neither expects to receive nor desires to leave any inheritance although the authors contended that the absence of a bequest motive was not critical to the heart of their results the assumption set off a long standing battle over the relative importance of different motives for saving in an influential study laurence kotlikoff and laurence summers 1981 estimated that a large fraction of the u s capital stock was attributable to intergenerational transfers modigliani and his collaborators vigorously disagreed and based on their own empirical work claimed that life cycle saving was the primary source of capital accumulation modigliani 1988 subsequent work has failed to reach a consensus since this debate began an important advance in the consumption literature has been the incorporation of uncertainty in life cycle models see e g r glenn hubbard et al 1995 we argue that allowing for uncertainty resolves the controversy over the importance of life cycle and bequest saving by showing that these motives for saving are overlapping and cannot generally be distinguished a dollar saved today simultaneously serves both a precautionary life cycle function guarding against future contingencies such as health shocks or other emergencies and a bequest function because in the likely event that the dollar is not absorbed by these contingencies it will be available to bequeath to children or other worthy causes under this view households have a bequest motive but bequests are given i e the motive is operative in only some states of the world wealth is something like traveler s checks you take them along on vacation just in case but odds are they will remain uncashed and available for sundry goods after the journey is complete we first demonstrate the result using a simple model and then argue that this approach reconciles the apparent importance of bequests with households declared focus on life cycle saving finally we consider implications of our analysis

old sick alone and poor a welfare analysis of old age social insurance programmes all individuals face some risk of ending up old sick alone and poor is there a role for social insurance for these risks and if so what is a good programme a large literature has analysed the costs and benefits of pay as you go public pensions and found that the costs exceed the benefits this article instead considers means tested social insurance mtsi programmes for retirees such as medicaid and supplemental security income we find that the welfare gains from these programmes are large moreover the current scale of mtsi in the u s is too small in the following sense if we condition on the current social security programme increasing the scale of mtsi by 1 3 benefits both the poor and the affluent when a payroll tax is used to fund the increase

on the theory of strategic voting many analyses of plurality rule elections predict the complete coor dination of strategic voting and hence support for only two candidates here i suggest that stable multi candidate support will arise in equilibrium a group of voters must partially coordinate behind one of two challenging candidates in order to dislodge a disliked incumbent in a departure from existing models the popular support for each challenger is uncertain this support must be inferred from the private observation of informative signals such as the social communication of pref erences throughout the electorate or the imperfect observation of opinion polls the uniquely stable voting equilibrium entails only limited strategic voting and hence incomplete coordination this is due to the surprising presence of negative feed back an increase in the degree of strategic voting by others reduces the incentives for an individual to vote strategically the incentive to vote strategically is lower in relatively marginal elections after controlling for the distance from contention of a trailing preferred challenger a calibration of the model applied to the uk general election of 1997 is consistent with the impact of strategic voting and the reported accuracy of voters understanding of the electoral situation it suggests that nearly 50 seats may have been lost by the conservative party due to strategic voting 1 plurality rule elections and strategic voting 1 1 strategic voting and duverger s law plurality rule elections where the winner is the candidate who receives the largest number of votes are vulnerable to strategic voting a voter might well switch away from her preferred candidate and toward a perceived leader in the hope of exerting a greater influence over the outcome of the election this phenomenon has long been the focus of both economic and political scientific study in an influential essay riker 1982b cited droop s 1871 eloquent exposition of the strategic voting problem 1 i oer my grateful thanks to the many friends colleagues seminar participants referees and editors who have oered insightful comments during the long gestation of this paper its antecedents and companion work special thanks go to steve fisher whose empirical analysis of strategic voting raised many of the questions that i seek to answer in this paper and to chris wallace this particular paper brings together much of the analysis previously circulated in the papers a new theory of strategic voting strategic voting under the qualified majority rule and idiosyncrasy information and the impact of strategic voting

what did medicare do the initial impact of medicare on mortality and out of pocket medical spending abstract we study the impact of the introduction of one of the major pillars of the social insurance system in the united states the introduction of medicare in 1965 our results suggest that in its first 10 years the establishment of universal health insurance for the elderly had no discernible impact on elderly mortality however we find a substantial reduction in the elderly s exposure to out of pocket medical expenditure risk specifically we estimate that the introduction of medicare was associated with a 40 decline in out of pocket spending for the top quartile of the out of pocket spending distribution a stylized expected utility framework suggests that the welfare gains from such reductions in risk exposure alone may be sufficient to cover almost two fifths of the costs of medicare these findings underscore the importance of considering the direct insurance benefits from public health insurance programs in addition to any indirect benefits from an effect on health

stability and coordination in duverger s law a formal model of preelection polls and strategic voting this paper investigates the dynamics of the wasted vote phenomenon and duverger s law i construct a theoretical model in order to consider how preelection polls serve to inform the electorate about the relative chances of the candidates and how that information acts over time to decrease the support of the trailing candidate the results shed light on how public opinion polls can aggregate information in the electorate and coordinate voters on the viable candidates in the election specifically i show that in a bayesian game model of strategic voting there exist non duvergerian equilibria in which all three candidates receive votes in the limit these equilibria require extreme coordination however and any variation in beliefs leads voters away from them to one of the duvergerian equilibria thus non duvergerian equilibria are unstable while two party equilibria are not in addition i describe how preelection polls provide information to voters about the viability of candidates and can thus be used by voters to coordinate on a duvergerian outcome

sequential voting in large elections with multiple candidates abstract i analyze strategic voting incentives in large elections with three candidates when voting takes place sequentially voters have perfect information about their private preferences but do not know the distribution from which other voters preferences are drawn if a candidate finishes last in an early voting round voters deduce that this candidate is likely to be less popular amongst the remaining voters and the remaining voters almost always have an incentive to stop voting for this candidate by contrast sincere voting equilibria can exist under either simultaneous voting or an early voting round of sequential voting without knife edge assumptions

does medicare benefit the poor abstract measuring the progressivity of age targeted government programs is difficult because no single data set measures income and benefit use throughout life previous research using zip code as a proxy for lifetime income has found that medicare benefits flow primarily to the most economically advantaged groups and that the financial returns to medicare are often higher for the rich than the poor however our analysis produces the starkly opposed result that medicare is an extraordinarily progressive public program in dollar terms or welfare terms these new results owe themselves to our measurement of socioeconomic status as an individual s education rather than the geographically aggregated measures of income used by previous research we argue that individual education has important practical and conceptual advantages over geographically aggregated measures of income our results suggest the crucial importance of accurate poverty measurement in evaluating the progressivity of complex government programs like medicare or social security

measurement error and earnings dynamics some estimates from the psid validation study previous empirical work on measurement error in survey earnings data has shown that the variance of the measurement error is roughly constant over time it is negatively correlated with true earnings and it is autocorrelated with previous measurement errors this article proposes a simple model in which the measurement error stems from underreporting of transitory earnings fluctuations and a white noise component the model fits well to data from the panel study of income dynamics validation study the results imply that autocorrelations in the changes of earnings can be estimated relatively accurately despite the presence of measurement error