New Releases by Laurence J. Kotlikoff

The U.S. and other western economies are experiencing dramatic changes in growth and age structure of their populations. Fluctuations in birth rates are the most important determinants of these changes in the post war period. This paper examines the dynamic effects of baby "booms" and baby"busts" on a range of economic variables using a perfect foresight life cycle simulation model. In addition to describing general transition (as opposed to simply long run) affects of fertility change, the paper considers alter-native Social Security policies for avoiding sharp increases in long run payroll tax rates. These include reductions in benefit replacement rates, advances in Social Security''s retirement age, taxation of social security benefits, and the accumulation of a significant Social Security trust fund. According to the simulated demographic transitions, the savings inthe U.S. fertility currently underway can have very major impacts on long run factor returns and produce percipitous short term changes in saving rates. While Social Security policy has important effects on the simulated demographic transitions, these effects are of secondary importance to the long run level of economic welfare. Even if payroll tax rates rise dramatically, long run welfare (measured in terms of levels of adult consumption and leisure) is, nonetheless, substantially higher in the case of a sustained dropin the fertility rate. This reflects, in part, the decline in the number of dependent children per adult; while a sustained decline in the fertility rate eventually means a much larger ratio of elderly per capita, the decline in children per capita means an overall decline in the long run ratio of dependents to prime age workers in the economy. A second explanation for the simulated long run welfare gains is capital deepening associated with lower population growth rates

Distingiishing "spot" versus "contract" views of the labor market is of critical importance to a host of economic issues ranging from wage flexibility over the business cycle to firm financial valuation. The structural features of U.S. private pension plans permit surprisingly strong inferences concerning the incentive effects of private pension plan provisions and the contractual nature of the U.S. labor market. This paper examines the accrual of vested pension benefits of a nation-wide sample of pension plans. We find strikingly larged is continuities in the profile by age of the ratio of annual accrued pension benefits to the standard wage. These discontinuities primarily occur at the ages of full vesting and early retirement. Representative plans often exhibit absolute changes in accrual ratios of 20 to 30 percentage points at these ages.The provisions of many plans imply large negative accruals after the age of early retirement. Job change typically involves a large loss in pension wealth as well. Since the average worker''s marginal product presumably changes smoothly as he or she ages, these pension data can only be reconciled with spotmarket clearing if age wage profiles within a firm exhibit exactly offsetting discontinuities at key ages. Casual inspection of firm wage setting behavior rules out this requirement of spot market clearing. In our view the magnitude,patterns, and variations in pension accrual ratios are strikingly at odds with spot market equilibrium. While market clearing in longer term contracts seems the only equilibrium theory consistent with these findings, it also strains our credulity to ascribe optimizing behavior to the pension accrual profiles chosen by a vast array of U.S. businesses. In the process of presenting these profiles we also consider the following questions concerning U.S. pensions. What are the incentive effects of private pension plans? What is the cost in pension benefits of job turnover? How important is vesting? Is there a cost in pension benefits of foregoing the early retirement option? Do pension stipulations encourage early retirement? While the considerable heterogeneity of pension plan provisions permits no simple or single answer to these questions, the data suggest that pensions can have major incentive effects on job turnover and retirement. In general pensions represent a very significant factor, and at certain ages, a dominant factor in employee compensation.

The proportion of workers covered by pensions has increased very substantially over the past two or three decades, and in particular the number of older workers with pensions continues to increase. During the same period, and especially in the past decade, the labor force participation of older workers has declined dramatically. These two trends may well be related. This paper examines the incentive effects of private pensions. We find that the provisions of pension plans provide very substantial incentives to terminate work at the current job after the age of early retirement and even greater incentives to leave after the age of normal retirement. It is not unusual for the reduction in pension ''benefit accrual after these retirement ages to equal the equivalent of a 30 percent reduction in wage earnings. In addition to a potentially large impact on labor force participation of older workers, pension plan provisions are likely to have important effects on labor mobility of younger workers.

The effect of social security and other forms of government debt on national savings is one of the most widely debated policy questions in economics today. Some estimates suggest that social security has reduced U.S. savings by almost forty percent. This paper examines recent cross-section and time series empirical tests of the social security-savings question and argues that, given current data, neither type of test has much potential for settling the controversy. In particular, there are a number of specification problems relating to social security time series regressions that can easily lead to highly unstable coefficients and to rejection of the hypothesis that social security reduces savings, even if it is actually true. These points are demonstrated by running regressions on hypothetical data generated by a perfect foresight life-cycle growth model developed previously by the authors. While the data is obtained from a model in which social security reduces the nation''s capital stock by almost twenty percent, time series social security regression coefficients vary enormously depending on the specified level of the program, the preferences of hypothetical households, the level of concommitant government policies, and the time interval of the data

This article examines how the availability of annuities affects savings and inequality in economies in which neither private nor public pensions initially exist. The absence of widespread market or government annuity insurance is clearly descriptive of many less developed countries in the world today; it was also a characteristic of virtually all countries prior to World War II. The paper compares economies with perfect insurance with economies in which completely selfish parents and children pool longevity risk to their mutual advantage. The analysis of the latter economies takes into account the infinite sequence of risk sharing bargains of successive parents with their children. Such bargains affect current risk sharing between parents and child because they determine the welfare of current children when they become parents. Calculations based on the CBS utility function indicate that perfecting annuity insurance can significantly reduce national savings. Indeed, the insurance aspects of government pensions are potentially as important as underfunding government pensions in reducing national savings.