Stanford workshop brings tools of demography to other disciplines

By Lisa Kwiatkowski

Stanford is ushering in a new approach to studying populations—one that engages researchers from multiple disciplines, including anthropology, biology, economics and sociology. The goal is to encourage the use of demographic tools to solve some of today's complex challenges, such as the demographic impact of the AIDS epidemic, population aging and the possible extinction of some species.

"Pick any problem in the world, and I can guarantee there is a population component to it," said James Holland Jones, an assistant professor of anthropological sciences. "Training in formal demography has all but disappeared at a time when so many problems call for demography."

Shripad Tuljapurkar, professor of biological sciences and the Dean and Virginia Morrison Professor of Population Studies, kicked off the "Second Stanford Workshop in Formal Demography," held on campus Aug. 7-12. He presented a surprising problem: declining fertility rates around the world. For years, industrialized countries worried about the negative implications of overpopulation, including environmental impacts and resource limitations. Today, the concern is shifting from overpopulation to low fertility.

The fertility rate is the average number of children a woman bears in her lifetime, and demographers say a rate of 2.1 is needed to keep a population from declining. A number of countries have now fallen below the replacement rate, including Japan, France, Germany, Italy, the United Kingdom and even China, whose total fertility rate has dropped from 5.8 in the 1970s to an estimated 1.73 today. In Hong Kong and Singapore, the fertility rate is even lower, estimated at 0.95 and 1.06, respectively.

"What happens in 20 years?" Tuljapurkar asked the graduate students and postdoctoral fellows attending the workshop. "That is a frightening rate of decline, especially in smaller countries."

In June, when Japan's health ministry announced that the country's fertility rate had fallen to an all-time low of 1.25, Prime Minister Junichiro Koizumi said it would become one of the most important items on the policy agenda. Tuljapurkar explained to students that one concern about low fertility rates is that economic growth has been tied to population size. Another concern is that pension programs, such as Social Security, depend on the renewal of the working-age population. Tuljapurkar recently was appointed to the Technical Advisory Panel to the U.S. Social Security Advisory Board and has published extensively in demography.

Some countries are taking steps to shore up their populations by using advertisements to encourage women to have children or by selectively increasing immigration. But do policymakers know what causes low fertility rates and what levers would be most effective in stemming the decline? Stanford's demography workshop, sponsored by the National Institutes of Health, Stanford's Institute for Research in the Social Sciences and Stanford's Morrison Institute for Population and Resource Studies, teaches students and researchers how to find answers through improved demographic analyses.

"The workshop is a new model of training we are implementing with 15 faculty and 40 students—mostly PhDs—from across the country," Jones said. "We're trying to push innovative methodologies for demographers by covering formal demography, related analytical methods and models that are formulated as computer programs."

Jones and Tuljapurkar organized the workshop and are publishing a textbook and software package to supplement the training. Unlike many demographers who are sociologists, Jones is a biological anthropologist and Tuljapurkar is a biologist and demographer.

"We have a strong evolutionary and biodemography component. Incorporating ideas from evolutionary biology is an exciting new direction for formal demography," Jones said. "Consider the question of how we project the future numbers of the 'oldest old'—those 85 years and older who are expected to represent an increasing percentage of the total elderly. Longer term, this question cannot be answered without understanding the complex ways genes and environments interact to produce patterns of aging and possible limits to lifespan. Evolutionary biodemography is the discipline with the tools to answer this question."

Tuljapurkar added that, in the nearer term, "formal demography provides tools for the effective projection of population aging and is key to policy regarding U.S. and other pension programs."

Teaching others these methods is beginning to bear fruit. At the Population Association of America meeting in Los Angeles this year, Jones noted that many of the presenters were using methods learned at last year's demography workshop at Stanford.

"Among researchers and policymakers, the methods we teach here are a very big deal," he said.

Lisa Kwiatkowski is director of communications for the School of Humanities and Sciences.

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