This is the fourth part of an ongoing series of interviews by CREA with workers in the field of aging.

Dr. Ronald Lee

UCB Professor of Demography

Ronald Lee has spent the past 30 years studying the causes and consequences of population change, with particular emphasis on economic and social roles played by the elderly. Among his accomplishments have been the introduction of stochastic modelling to give improved estimates of the forthcoming U.S. population shift in this century; a recognition of the importance of intergenerational transfers throughout human societies past and present; and a novel extension to the traditional evolutionary theory of aging that proposes a vital role for the elderly as caregivers.

In an effort to influence public policy, Lee testified before Congress in 2001 to give his probabilistic forecasts of the number of American elderly throughout the 21st century, and resulting budgetary projections. One useful measurement of population aging is the old age dependency ratio, which is the ratio of elderly population to the working-age population. Traditional measures used by the Social Security Administration (SSA), he believes, have underprojected the old age dependency ratio somewhat, because they have discounted the continuous and regular decline in US mortality over the 20th century. In addition, they have substantially underestimated the uncertainty of their forecasts, and this can be remedied by using Lee's probabilistic models. Declining mortality and low fertility will lead to the proportion of elderly dependents to productive workers more than doubling by 2075, suggesting that a greater policy shift than the SSA originally anticipated will be required to keep Social Security afloat.

The current state of Social Security, Lee suggests, is a consequence of the demographic and technological shifts of our society in the past century. Economically, the young and the old are both resource sinks in any society, in that they ultimately consume more than they produce. This imbalance is compensated for by those of working age, who must collectively produce enough resources to transfer both upward (to their elderly parents) and downward (to their young children). For the hunter-gatherers who inhabit the bulk of human history, life expectancy was low and getting food was hard, so these intergenerational transfers were most often downward. As we developed agriculture, children were able to contribute to their own needs earlier in life, and so they became more of an asset to their parents. Overall, downward transfers decreased.

In modern America, there has been another fundamental shift in the mechanics of intergeneration transfer. Today, workers funnel more of their resources to the state than ever before, and public transfers -- of which Social Security is most prominent -- have usurped private familial transfers as the dominant means of support for the elderly. At the same time, downward transfers to children are steadily decreasing, in part because there is very little economic incentive for Americans to have children. Lee says, "In a public system it doesn't matter whether you've had kids or not -- society will support you in your old age." This societal glut of old and dearth of young can lead to a vicious cycle in which "public expenditures on everything but the elderly are compressed," giving short shrift to public transfers to the young (in education, for example) and ultimately limiting the future contributions they can make to the system.

Lee terms this scenario a "fiscal nightmare" for the federal government, and he doesn't believe that there are any easy solutions -- including the obvious one of raising the Social Security eligibility age. "We've found that raising the benefits age won't cause people to retire later," he says. Instead, it causes them to retire at the same age as in the past with a smaller cut of their share, resulting in decreased standards of living.

Still, Lee thinks that it is possible to fix Social Security and maintain our public transfer system by "tweaking some knobs" -- for example, by raising payroll taxes by about 4%. And although he sees Medicare as a tougher facet of our transfer imbalance problem, Lee still favorably compares our situation overall to that in Europe, where there is both a lower overall birthrate and national pension programs structured such that the elderly often "have greater benefit to retire than to work." By contrast, "most people opt to work longer in low-tax societies," because they have more of an incentive to acquire personal savings for retirement.

One factor that cannot be accurately placed in Lee's demographic model is the impact of future advances in public health and biomedicine. "Scientific discovery is a huge factor in demographic prediction," says Lee, but it is also inherently unpredictable. Lee takes technological advances into account in his forecasts by noting that they have caused mortality decline to "chug along at about the same pace" over the past century, despite dramatic biomedical discoveries such as antibiotics and the emergence of deadly new diseases like HIV/AIDS. It is not lost on him that dramatic research advances in the future, depending on their nature, could either deepen our national public transfer problems (by increasing the number of dependent elderly) or lessen them (by increasing the number of independent elderly).

Most recently, Lee has taken interest in how intergenerational transfers may have affected the evolution of longevity itself. An accepted evolutionary explanation for aging goes something like this: natural selection acts strongly to remove genes from the population that cause high mortality and poor health at young ages, while most reproduction still lies in an organism's future. However, as an organism ages, a smaller and smaller share of its life time reproduction lies in its future, and it matters less and less to its reproductive fitness whether it lives or dies. For this reason, mutations with bad effects at older ages accumulate in the population, causing rising mortality and deteriorating vigor and function. The slow deterioration that we know as aging is the natural result.

Lee does not disagree with this idea, but he has extended it to take account of the continuing postreproductive influence of parents on their reproductive fitness in many species by investing in their offspring, and improving their survival and reproductive success. In traditional hunter-gatherer societies, a natural fit for the elderly would be in providing care for their grandchildren, leaving their adult children (the producers) free to acquire more resources. In other words, Lee proposes that the elderly have traditionally more than pulled their own weight by providing a downward transfer of time to their adult children and grandchildren.

Regarding his own career, Lee describes himself as having come to a career in demography on a lark. After studying philosophy as an undergraduate, he taught school in Ethiopia in the Peace Corps during the 60s. Afterward, he says, "I wanted to be a grad student at large, but such a thing didn't exist." As a Master's student in the new demography program at Berkeley, he "expected a philosophical approach to mortality, but the first class I walked into I saw calculators on all the desks! I almost walked right back out." Later, Lee received a doctorate in Economics. Afterward, he came to study what he calls the "central variable" of age in demography by a process of natural progression more than through any conscious decision.