price setting during low and high inflation evidence from mexico this paper provides new insight into the relationship between inflation and the setting of individual prices by examining a large data set of mexican consumer prices covering episodes of both low and high inflation when the annual rate of inflation is low below 10 15 the frequency of price changes comoves weakly with inflation because movements in the frequency of price decreases and increases partly offset each other in contrast the average magnitude of price changes correlates strongly with inflation because it is sensitive to movements in the relative shares of price increases and decreases when inflation rises beyond 10 15 few price decreases are observed and both the frequency and average magnitude are important determinants of inflation i show that a menu cost model with idiosyncratic technology shocks predicts the average frequency and magnitude of price changes well over a range of inflation similar to that experienced by mexico

college scholarship rules and private saving this paper examines the effect of existing college scholarship rules on the incentive to save the analysis shows that families that are eligible for college scholarships face education tax rates on capital income of between 22 percent and 47 percent in addition to regular federal and state income taxes the empirical analysis developed here based on the 1986 survey of consumer finances implies that these high tax rates have a powerful adverse effect on the accumulation of financial assets copyright 1995 by american economic association

capital taxation and accumulation in a life cycle growth model almost all of the serious economic work on savings decisions within the past decade has relied on some variant of the life cycle hypothesis in which savings arise out of individual choices of an optimum lifetime consumption path this paper reexamines the incidence and welfare consequences of capital income taxes within a realistic life cycle model the results suggest that the elimination of capital income taxation would have very substantial economic effects for example a complete shift to consumption taxation might raise steady state output by as much as 18 percent and consumption by 16 percent the long run welfare gain from such a shift would for plausible parameter values exceed 150 billion annually stated somewhat differently shifting to consumption taxation would raise the lifetime utility of the representative consumer by the equivalent of about six years income in the new steady state these estimates dwarf estimates of the static welfare cost of taxation and significantly exceed even extreme previous estimates of the dynamic loss this study departs from earlier analyses of the effects of taxes on capital income in several respects probably the most important difference between this treatment and most preceding ones lies in the assumptions about the interest elasticity of saving it is shown below that the common two period formulation of saving decisions yields quite misleading results a more realistic model of life cycle savings demonstrates that for a wide variety of plausible parameter values savings are very interest elastic this implies that shifting away from capital income taxation would significantly increase capital formation making possible long run increases in consumption many studies of the welfare effects of capital income taxation have ignored the general equilibrium effects of increased capital formation in an economy with life cycle savings there is no presumption that the undistorted growth path corresponds to any sort of social optimum as peter diamond has shown life cycle savings can lead to a steady state capital intensity either greater or less than the golden rule level more generally it is clear that there is no reason to believe that a life cycle economy will maximize any particular intertemporal social welfare function a fundamental tenet of welfare evaluation is that preexisting distortions must be considered in evaluating the consequences of tax changes the results presented in this paper take explicit account of the nonoptimal character of the no tax steady state this explains in large part why such a sizeable welfare effect of capital taxes is found in an economy far from the golden rule level of capital intensity there are substantial gains in steady state consumption achievable through increased capital formation section i of the paper examines the aggregate savings function in a continuous time life cycle framework the second section clarifies the differences between wage and consumption taxes an aggregate production function is added to complete the model in the third section the effects of changes in capital taxes on both steady state incidence and welfare are considered within a general equilibrium framework the final section of the paper discusses some implications of the results and suggests areas which appear to warrant further study assistant professor of economics massachusetts institute of technology and research analyst national bureau of economic research i am grateful to alan auerbach martin feldstein laurence kotlikoff to the participants in the nber workshop on business taxation and to the harvard public finance seminar for useful discussions james poterba and james buchal performed the numerical calculations

policy options in a liquidity trap the specter of a liquidity trap originally proposed as a theoretical possibility by john maynard keynes 1936 but long considered to be of doubtful practical relevance has recently created alarm among the world s central banks in japan the overnight rate has been essentially at zero for most of the time since february 1999 making further interest rate cuts impossible yet until well into 2003 growth remained anemic while prices continued to fall suggesting a need for further monetary stimulus since march 2001 the bank of japan has supplemented its zero interest rate policy with a policy of quantitative easing under which additional bank reserves are supplied beyond those needed to keep overnight interest rates at zero yet an increase in base money of more than 50 percent failed to halt the deflation suggesting a liquidity trap more recently other central banks including the fed have come close enough to the zero bound to worry about how they would deal with a similar predicament here we first discuss whether monetary policy should actually become ineffective when the zero bound on interest rates is reached we argue that open market operations even of unconventional types will be ineffective if they do not change expectations about the future conduct of policy in this sense a liquidity trap is possible nonetheless a credible commitment regarding future policy can largely mitigate the distortions created by the zero bound we fully characterize the optimal commitment in a simple example

production function regressions returns to scale and externalities a number of recent papers have used simple linear regressions in an attempt to identify market structure the extent of returns to scale and possible external effects in u s manufacturing industries the results obtained from these regressions have important implications for several branches of modern macroeconomics as a result the macro literature frequently cites specific numerical evidence from caballero and lyons 1992 and hall 1990 which suggests that there are quantitatively significant increasing returns to scale or external effects in u s manufacturing in contrast it is the argument of this paper that this evidence is not convincing the most robust evidence suggests that the typical u s manufacturing industry displays constant returns with no external effects on the other hand there is significant heterogeneity across industries

monetary policy trend inflation and the great moderation an alternative interpretation with positive trend inflation the taylor principle does not guarantee a determinate equilibrium we provide new theoretical results on determinacy in new keynesian models with positive trend inflation and new empirical findings on the federal reserve s reaction function before and after the volcker disinflation to find that i while the fed likely satisfied the taylor principle before volcker the us economy was still subject to self fulfilling fluctuations in the 1970s ii the us economy switched to determinacy during the volcker disinflation and iii the switch reflected changes in the fed s response to macroeconomic variables and the decline in trend inflation jel e12 e23 e31 e32 e52

panel discussion price stability how should long term monetary policy be determined these comments address the question of monetary strategy as distinct from monetary tactics they are not directed at the question of what monetary policy is appropriate at the present time or of how monetary policy should be determined at any specific point as a function of prevailing conditions instead the issue i take is one that has been of increasing interest to economists in recent years what should be the long terrn objectives of the monetary authority increased interest in this issue as opposed to the issue of fine tuning the economy reflects the general intellectual consensus that has emerged on two points first what the monetary authority surely can control in the long run is the growth rate of nominal income second issues of dynamic consistency and commitment are crucial to the design of appropriate monetary policies beyond its recognition of these points my view is that most of what the academic economics community has had to say on the issue of long run monetary strategy has been tangential at best and i fear that many of the papers at this conference have not done much to improve the situation i wish to advance four propositions about monetary policy and to discuss their implications first an optimal tax theory has little or nothing to do with sensible inflation policy second positive rates of inflation are almost certainly desirable third to an important extent institutions do the work of rules and monetary rules should be avoided instead institutions should be drafted to solve time inconsistency problems fourth h j res 409 the proposed zero inflation amendment is a good idea if it is not taken too seriously or too literally but is instead viewed as a device for strengthening the independence of the federal reserve system my first proposition is that the connection between optimal tax theory and infla

tax policy the interest elasticity of saving and capital accumulation numerical analysis of theoretical models increasing disillusionment with traditional empirical methods is having a major impact on research methodology which is increasingly turning to simulation analysis based on theoretical models and assumed parameter values in research on saving and wealth accumulation there have been several recent studies consisting of simulation of theoretical models based on the life cycle model a particular focus has been tax policy and capital formation which is the area of concentration of this paper the aim is to analyze in a theoretical simulation context the impact on saving and wealth of an increase in the after tax rate of return to saving generated by a cut in the tax rate on income from capital this paper suggests that such simulation analysis while instructive as to the behavior of the class of models examined and as to the critical channels of influence does not yield a theoretical presumption in favor of cutting taxes on income from capital as a means of stimulating capital formation the development of this literature derives in part from disillusionment with traditional empirical methods many such papers begin by listing a litany of the problems involved in the usual type of empirical analysis before proceeding to simulation of theoretical structures the implicit conclusion at times appears to be that because of the daunting problems of standard empirical methodology the results derived from it can be ignored and that empirical magnitudes can perhaps be discovered by deductive means the temptation to think of the precise numerical results derived from theoretical simulation as empirical can be rather strong it needs to be reemphasized that empirical magnitudes can only be determined by empirical studies in section i the theoretical structure of a zero bequest life cycle model2 is outlined and several numerical simulations of this model are presented these simulations highlight interesting and nontrivial interactions of theoretical parameters and also demonstrate the difficulty involved in attempts to develop robust aggregate implications from such a framework for instance it is argued that summers claim to have developed a prima facie theoretical case for a high interest elasticity of savings 1981a p 537 does not stand up to sensitivity analysis a small change in the assumed rate of pure time preference or in other parametric assumptions generate otherwise plausible cases in which the interest elasticity of aggregate saving is low the experiments conducted in section i are partial equilibrium in the sense that the interest rate is changed exogenously which changes savings and hence the capital stock but the feedback effect of the capital international monetary fund this paper derives from chs 2 and 3 of my doctoral dissertation completed during a research fellowship at the brookings institution financial support was received from brookings and the social science research council i am grateful to henry aaron barry bosworth maxim engers irwin friend laurence kotlikoff franco modigliani joseph pechman duncan ripley robert shiller patricia stack and my supervisor albert ando for comments and guidance on earlier drafts none of the above institutions or individuals is responsible for the views expressed or any remaining errors for example see james tobin and walter dolde betsy white lawrence summers 1978 1981a b g moore alan auerbach and laurence kotlikoff and auerbach kotlikoff and j skinner 2it is popular to establish a sharp dichotomy between life cycle models and bequest models this taxonomy ignores the frequent references to the potential significance of bequests in the writings of the originators of the life cycle hypothesis a distinction between zero bequest life cycle models and life cycle models incorporating bequests is more accurate in terms of doctrinal history see for example albert ando and franco modigliani and modigliani and richard brumberg

real implications of the zero bound on nominal interest rates if monetary policy succeeds in keeping average inflation very low nominal interest rates may occasionally be constrained by the zero lower bound the degree to which this constraint has real implications depends on the monetary policy feedback rule and the structure of price setting policy rules that make the price level stationary lead to small real distortions from the zero bound if policy imparts persistence into the inflation rate the real implications of the zero bound are large in the presence of backward looking price setting and small if prices are set to maximize profits

the impact of asset tested college financial aid on household savings abstract federal college financial aid imposes an implicit tax on asset accumulation which reduces the incentive for families to save prior literature has found evidence of large reductions in asset accumulation as a result this paper finds that these conclusions are over estimated and are sensitive to the assumptions used in estimating the implicit tax rate additionally the 1992 exemption of home equity and other changes in federal policy have substantially eliminated the savings disincentive for many families thus the results of studies that examined families prior to the 1992 changes cannot be applied to the current program

quits layoffs and job destruction we examine the quit layoff distinction and its implications for job destruction from the employer s perspective using a set of panel data of dutch firms we get the following results first in addition to layoffs quits contribute to the speed of downward adjustment of labour second about 22 of the jobs of workers who resigned are destroyed it is not clear cut whether these resignations are initiated by employers or employees

the after tax rate of return affects private savings level of savings and the rate of capital formation are of central concern to both economists and policymakers although the welfare effects of tax reforms do not directly depend on their impact on savings the effects of taxes on savings is crucial to considerations of tax incidence and equity and to the issue of long run growth the impact of the rate of return on consumption and savings decisions also bears on questions regarding the appropriate government discount rate the short run crowding out effects of fiscal policy and the effects of public indebtedness on capital intensity the traditional view among economists is that changes in the rate of return are likely to have only a small effect on the savings rate this consensus is supported by theoretical arguments pointing to the opposing income and substitution effects associated with changes in the rate of return the ambiguous implications of theory are matched by empirical studies which yield conflicting estimates as to the size of the impact of changes in the rate of return the polar empirical estimate is michael boskin s 1978 suggestion that the interest elasticity of savings is 4 this estimate is widely regarded as too high

inflation and unemployment the world economy today is vastly different from the 1930s when seymour harris the chairman of this meeting infected me with his boundless enthusiasm for economics and his steadfast confidence in its capacity for good works economics is very different too both the science and its subject have changed and for the better since world war ii but there are some notable constants unemployment and inflation still preoccupy and perplex economists statesmen journalists housewives and everyone else the connection between them is the principal domestic economic burden of presidents and prime ministers and the major area of controversy and ignorance in macroeconomics i have chosen to review economic thought on this topic on this occasion partly because of its inevitable timeliness partly because of a personal interest reaching back to my first published work in 1941

the welfare costs of moderate inflations in the recent past the view that a little bit of inflation was good for the economy was widely held the phillips curve in its earlier incarnations implied that moderate inflation was worth tolerating because it would permit lower unemployment this justification for tolerating inflation has long since been abandoned by economists and policymakers because both theory and experience showed it to be false nevertheless one legacy of this era seems to be a fairly widespread tolerance for moderate inflation recently there has been much discussion of removing this inflationary bias by passing legislation that would require the federal reserve to target zero inflation in this paper we examine some of the consequences of achieving that goal we appraise the revenue and welfare costs of policies designed to reduce moderate inflation rates to zero much has been written about why government policies may have an inflationary bias in this paper we don t address the issue of what motivates governments to inflate implicit in our analysis however is the notion that one important motive for inflation is the revenue raising potential of the inflation tax it would be difficult to argue that the inflation tax constitutes an important revenue source for the united states one indirect and very imperfect measure of this would be contributions by the federal lleserve to the treasury in recent years those rebates have amounted to

risk premium shocks and the zero bound on nominal interest rates there appears to be a disconnect between the importance of the zero bound on nominal interest rates in the real world and predictions from quantitative dsge models recent economic events have reinforced the relevance of the zero bound for monetary policy whereas quantitative models suggest that the zero bound does not constrain optimal monetary policy

is college financial aid equitable and efficient nk reed based financial aid is often defended both on grounds of equity and efficiency equity because it provides equality of opportunity and efficiency because it encourages the formation of productive human capital james 1988 however need is now determined in a way that is both inequitable and inefficient an informal survey of my colleagues who do not study financial aid revealed no one who named the financial aid system as a substantial tax on savings however once this interpretation was suggested they quickly revealed their unanimous and disturbing impression that savings are summarily confiscated from parents upon their first child s matriculation at university though exaggerated this impression is not without foundation two families with identical earnings paths pay dramatically different amounts for college if one saves more than the other thus while the financial aid system may contribute to vertical equity since the poor get more aid than the rich its horizontal inequities are substantial moreover the federal rules for financial aid raise significant efficiency concerns 1 they might conceivably distort many household decisions including family size and the spacing of children however this paper will focus upon the most important incentive distorted by present policies the incentive to save because saving leads to receiving less financial aid a family s return to saving is substantially below the social return this may lead to families making inefficient intertemporal choices and correspondingly to an inefficient loss of capital formation

some canadian evidence on the quit lay off distinction the question of whether or not there exists a meaningful economic distinction between quits and layoffs has attracted considerable attention this paper utilizes a recent test proposed by j s cramer and g ridder 1991 to test formally whether quits and layoffs may legitimately be aggregated into a single undifferentiated job mover category the paper also estimates wage equations for job stayers quits and layoffs corrected for the endogeneity of job mobility the major results are that quits and lay off cannot legitimately be pooled and correction for sample selection would appear to be important

five facts about prices a reevaluation of menu cost models are price decreases 3 the frequency of price increases covaries strongly with inflation whereas the frequency of price decreases and the size of price increases and price decreases do not 4 the frequency of price change is highly seasonal it is highest in the first quarter and then declines 5 we find no evidence of upwardsloping hazard functions of price changes for individual products we show that the first second and third facts are consistent with a benchmark menu cost model whereas the fourth and fifth facts are not

the implicit taxes from college financial aid abstract families who earn more or who heed the experts advice and save for college typically receive less financial aid the financial aid system therefore implicitly taxes both income and assets we use npsas aid award data to estimate these implicit taxes and find that at average priced colleges the marginal income tax ranges from 2 to 16 and the marginal asset levy from 8 to 26 a typical family loses aid worth about 11 000 at average priced colleges and 15 000 at expensive colleges by accumulating an extra 50 000 in assets

the optimal inflation rate in new keynesian models should central banks raise their inflation targets in light of the zero lower bound we study the effects of positive steady state inflation in new keynesian models subject to the zero bound on interest rates we derive the utility based welfare loss function taking into account the effects of positive steady state inflation and solve for the optimal level of inflation in the model for plausible calibrations with costly but infrequent episodes at the zero lower bound the optimal inflation rate is low typically less than two percent even after considering a variety of extensions including optimal stabilization policy price indexation endogenous and statedependent price stickiness capital formation model uncertainty and downward nominal wage rigidities on the normative side price level targeting delivers large welfare gains and a very low optimal inflation rate consistent with price stability these results suggest that raising the inflation target is too blunt an instrument to efficiently reduce the severe costs of zero bound episodes

estimation of dsge models when the data are persistent dynamic stochastic general equilibrium dsge models are often solved and estimated under specific assumptions as to whether the exogenous variables are difference or trend stationary however even mild departures of the data generating process from these assumptions can severely bias the estimates of the model parameters this paper proposes new estimators that do not require researchers to take a stand on whether shocks have permanent or transitory effects these procedures have two key features first the same filter is applied to both the data and the model variables second the filtered variables are stationary when evaluated at the true parameter vector the estimators are approximately normally distributed not only when the shocks are mildly persistent but also when they have near or exact unit roots simulations show that these robust estimators perform well especially when the shocks are highly persistent yet stationary in such cases linear detrending and first differencing are shown to yield biased or imprecise estimates

staggered price setting with endogenous frequency of adjustment abstract a model of staggered price setting in which the frequency of price changes is endogenous is presented

imperfect information and labor market bias against small and medium sized enterprises a korean case we examine the labor market s bias against small and medium sized enterprises focusing on the seoul digital industrial complex case we adopt heckman s approach to control selection bias and use primary data from questionnaire surveys conducted at both firm and employee levels we find that conventional firm specific factors such as wages fringe benefits and weekly work hours primarily explain the labor market bias but imperfect information is also positively associated with the bias for example a firm s inadequate ability to identify a pool of potential employee candidates or to provide them comprehensive firm or job specific information tends to worsen labor shortages and an employee s ex ante incomplete knowledge of on the job training or education opportunities tends to increase ex post turnover intentions our results suggest that reducing the market bias requires improving imperfect information as well as conventional firm specific conditions

has u s monetary policy changed evidence from drifting coefficients and real time data despite the large amount of empirical research on monetary policy rules there is surprisingly little consensus on the nature or even the existence of changes in the conduct of u s monetary policy three issues appear central to this disagreement 1 the specific type of changes in the policy coefficients 2 the treatment of heteroskedasticity and 3 the real time nature of the data used this paper addresses these issues in the context of forwardlooking taylor rules with drifting coefficients the estimation is based on real time data and accounts for the presence of heteroskedasticity in the policy shock the findings suggest important but gradual changes in the rule coefficients not adequately captured by the usual split sample estimation in contrast to orphanides 2002 2003 i find that the fed s response to the real time forecast of inflation was weak in the second half of the 1970s perhaps not satisfying taylor s principle as suggested by clarida gali and gertler 2000 however the response to inflation was strong before 1973 and gradually regained strength from the early 1980s onward moreover as in orphanides 2003 the fed s response to real activity fell substantially and lastingly during the 1970s

monetary policy when potential output is uncertain understanding the growth gamble of the 1990s abstract t he fed kept interest rates low and essentially unchanged during the late 1990s despite a booming economy and record low unemployment these interest rates were accommodative by historical standards nonetheless inflation remained low how did the fed succeed in sustaining rapid economic growth without fueling inflation and inflationary expectations in retrospect it is evident that the productive capacity of the economy increased yet as events unfolded there was uncertainty about the expansion of the capacity of the economy and therefore about the sustainability of the fed s policy this paper provides an explanation for the success of the fed in accommodating growth with stable inflation in the late 1990s it shows that if the central bank is committed to reverse policy errors it makes because of unwarranted optimism inflation can remain in check even if the central bank keeps interest rates low because of this optimism in particular a price level target which is a simple way to model a commitment to offset errors can serve to anchor inflation even if the public does not share the central bank s optimism about shifts in potential output the paper shows that price level targeting is superior to inflation targeting in a wide range of situations the paper also provides econometric evidence that in contrast to earlier periods the fed has recently put substantial weight on the price level in setting interest rates moreover it shows that cpi announcement surprises lead to reversion in the price level finally it provides textual evidence that alan greenspan puts relatively more weight on the price level than inflation

trend inflation indexation and inflation persistence in the new keynesian phillips curve purely forward looking versions of the new keynesian phillips curve nkpc generate too little inflation persistence some authors add ad hoc backward looking terms to address this shortcoming we hypothesize that inflation per sistence results mainly from variation in the long run trend component of inflation which we attribute to shifts in monetary policy we derive a version of the nkpc that incorporates a time varying inflation trend and examine whether it explains the dynamics of inflation when drift in trend inflation is taken into account a purely forward looking version of the model fits the data well and there is no need for backward looking components jel e12 e31 e52 in this paper we consider the extent to which guillermo calvo s 1983 model of nominal price rigidities can explain inflation dynamics without relying on arbitrary backward looking terms in its baseline formulation the calvo model leads to a purely forward looking new keynesian

college tuition and household savings and consumption abstract despite the high cost of college there has been little study of the adequacy of household savings and other resources available to fund college to gauge their adequacy this paper examines households standard of living as they pay for college using the consumer expenditure survey the main finding is that households appear to do a relatively good job smoothing their consumption into the academic year despite large expenses this is consistent with the life cycle theory of saving and consumption there is some evidence of a delayed decline in consumption and of a decline for households with children first beginning college but the magnitudes of these declines are rather small

state dependent pricing and the general equilibrium dynamics of money and output economists have long suggested that nominal product prices are changed infrequently because of fixed costs in such a setting optimal price adjustment should depend on the state of the economy yet while widely discussed statedependent pricing has proved difficult to incorporate into macroeconomic models this paper develops a new tractable theoretical state dependent pricing framework we use it to study how optimal pricing depends on the persistence of monetary shocks the elasticities of labor supply and goods demand and the interest sensitivity of money demand

welfare costs of inflation in a menu cost model recent years have seen substantial prog ress in our understanding of pricing decisions at the micro level access to large scale data sources on prices of individual products has given us rich information on how frequently prices change by what magnitude and how the aggregation of price changes in individual firms maps into aggregate inflation see among many others mark bils and peter j klenow 2005 these facts about price movements are a key input in recent quantitative models of the aggre gate effects of nominal rigidities e g mikhail golosov and robert e lucas 2007 in this paper we use both the new facts and the new quantitative models to revisit an old question namely that of quantifying the welfare benefits of low inflation our model includes two

on endogenously staggered prices taylor s model of staggered contracts is an influential explanation for nominal inertia and the persistent real effects of nominal shocks however in standard imperfect competition models if agents are allowed to choose the timing of pricing decisions they will typically choose to synchronize this paper provides a simple model of imperfect competition which produces stable staggering our argument relies on strategic interaction at two levels between firms within an industries and across industries and produces a continuum of staggered price equilibria these equilibria are strict and hence stable under a simple adaptive learning process an enduring problem for business cycle theory is an explanation for the persistent effects of nominal shocks explaining persistence is particularly problematic for theories based on nominal shocks as opposed to real shocks this is because rational expectations implies that nominal shocks themselves cannot be serially correlated since nominal shocks are the deviation of realized nominal magnitudes from expected values in two important papers taylor 1979 1980 provided an argument as to why a nominal shock can have persistent effects taylor s argument required two important assumptions first he assumed that firms could adjust prices only in alternate periods an assumption which may be justified by menu or information costs taylor s second assumption was that price setting was staggered half the firms were constrained to adjust prices in odd periods while the other half were allowed to adjust prices in even periods these two assumptions combined to provide dramatic results on nominal inertia the adjustment of prices to a nominal shock is slow and hence output effects are long lasting taylor s results on persistence arise due to strategic complementarity between price setting decisions this implies that each firm s optimal price is an increasing function of the aggregate price level if a shock arrives in an even period firms in the even cohort will not adjust fully to the nominal shock since firms in the odd cohort have fixed prices in the current period furthermore with rational expectations the even cohort also takes into account the fact that its own failure to adjust fully will also make for partial adjustment in future periods this elegant story has made taylor s model possibly the most influential of new keynesian models by providing a dynamic setting within which small nominal rigidities may result in persistent nominal inertia

medicare reform the larger picture the medicare problem is examined as part of the larger problem of providing for the overall financial needs of the elderly several myths about medicare are discussed and sources and uses of the elderly s full income are estimated the paper explores policy options to deal with technology induced increases in health care expenditures and excessive dependence of the elderly on transfers from the young the paper concludes that if americans wish to continue to enjoy the benefits of medical advances they will have to work before and after age 65 and will have to increase their rate of saving substantially