Stanford University

Human Demographic Change and Contemporary Societies

The lab works on many (most) of the forces that affect the size and composition of human populations. Much of this work deals with changes in how long we live, how many kids we have, and how changing demography affects the present and future world.

Human Mortality Change and Forecasts
We have shown that human mortality rates in the past century have declined at an amazingly regular rate. We used these regularities to make probabilistic forecasts of mortality change in many countries, and have analyzed the whole business of forecasting mortality:

Tuljapurkar, S. 2008.  Mortality Declines, Longevity Risk and Aging.  Asia-Pacific Journal of Risk and Insurance 3(1): 37-51.

Boe, C. and Tuljapurkar, T. 1999.  Mortality change and forecasting: How much and how little do we know.  North American Actuarial Journal, 2: 13- 47.

Tuljapurkar, S. 1999.  Forecasting Mortality change: Questions and Assumptions. North American Actuarial Journal, 2: 127 - 134.

Tuljapurkar, S., Li, N. and Boe, C., 2000.  A universal pattern of mortality decline in the G 7 countries.  Nature, 405:  789-792.

Li, N., Lee, R. and Tuljapurkar, S. 2004. Using the Lee-Carter Method to Forecast Mortality for Populations with Limited Data.  International Statistical Review 72:  19-36.

Inequality in Age at Death
The variance in age at death (some die young) is an important measure of human inequality, and has declined dramatically over the past two centuries. Change continues, and captures important aspects of the social and technological change that shapes human mortality:

Tuljapurkar, Shripad. 2009. The Final Inequality: Variance In Age At Death. IN Demography and the Economy, John B. Shoven, Ed. NBER (in press).

Edwards, R., and Tuljapurkar, S. 2005. Inequality in Life Spans and a New Perspective on Mortality Convergence Across Industrialized Countries. Population and Development Review 31(4):645–674

Tuljapurkar, S.  2005. Future Mortality: A Bumpy Road to Shangri-La? Sci. Aging Knowl. Environ., Vol. 2005, Issue 14, p. 9, 6 April 2005.

Tuljapurkar, S.  2003.  The Emergence of Modern Human Mortality Patterns. In: The Evolution of Population Biology - Modern Synthesis.  Editors: Rama Singh, Marcy Uyenoyama, and Subodh Jain. Cambridge University Press.

Stochastic Population Forecasts, Pensions and Policy
In a long collaboration with Ronald Lee, we developed methods for making probabilistic population forecasts and applied them to social security, pensions, and fiscal policy.

Tuljapurkar, S.  2006.  Population forecasts, Fiscal Policy and Risk.  In Press  Government Spending on the Elderly, Dmitri B. Papadimitriou, Ed. Palgrave Macmillan, NY.

Tuljapurkar, S., Lee, R. and Li, Q.  2004.  Random scenario forecasts versus stochastic forecasts.  International Statistical Review 72(2):  185-199.

Tuljapurkar, S. and Lee, R., 2000.  Demographic uncertainty and the United States OASDI fund. IN, A. Mason and G. Tapinos, eds., Sharing the Wealth:  Demographic Change and Economic Transfers Between Generations. Oxford University Press, pp. 195-208.

Lee, R. and Tuljapurkar, S., 2000.  Population forecasting for fiscal planning: Issues and innovations, In:  Alan Auerbach and Ronald Lee, eds., Demography and Fiscal Policy. Cambridge University Press, pp. 7-57.

Tuljapurkar, S. and Boe, C. 1999. Validation, information and probabilistic priors in stochastic forecasts.  International Journal of Forecasting, 15:  259 – 271.

Tuljapurkar, S. and Lee, R.  1998.  Stochastic forecasts for Social Security.  In: David Wise, ed. Frontiers in the Economics of Aging. Chicago: University of Chicago Press, pp.393-420.

Lee, R. and Tuljapurkar, S. 1998.  Uncertain demographic futures and Social Security finances. American Economic Review, 88(2): 237-241.

Lee, R. and Tuljapurkar, S. 1997.  Death and Taxes: How Longer Life Will Affect Social Security.  Demography 34: 67 - 81.

Tuljapurkar, S. 1997.  Taking the measure of Uncertainty, Nature 387:  760 – 761.

Population and Policy Around the World
We’ve applied our methods to many countries:

Tuljapurkar, S. 2009. Demography: Babies make a comeback. Nature 460, 693-694

Tuljapurkar, S. 2008.  The UPE forecasts:  strengths, innovations, developments.  In:  Uncertain Demographics and Fiscal Sustainability, J. Alho, S. Jensen and J. Lassila, eds., Cambridge University Press, pp. 55-61.

Tuljapurkar, S. 2003. Stochastic Forecasts of Mortality, Population And Pension Systems.  In: Bengtsson, T. & N. Keilman (eds.) Perspectives on Mortality Forecasting.  Social Insurance Studies, Vol. 2, pp. 65-77.  Stockholm: Swedish National Social Insurance Board

Ogawa, N., Kodo, M., Tamira, M., Matsukura, T., Saito, T., Mason, A., Tuljapurkar, S. and Li, Nan.  2002.  Long-term Perspectives for Japan:  An analysis based on a macroeconomic-demographic-social security model with emphasis on human capital. (In Japanese) Nihon-University Population Research, Japan.

Tuljapurkar, S., Li., N., and Anderson, M.  2002.  Stochastic Population Forecasts for the G-7 Countries.  Pp. 116-140, In:  England, R. “The Fiscal Challenge of an Aging Industrial World.”  Washington DC:  Center for strategic and International Studies.

Anderson, M., Tuljapurkar, S. and Li, N., 2001.  How accurate are demographic projections used in forecasting pension expenditure?  In: Tito Boeri, Axel Borsch-Supan, Agar Brugiavini, Richard Disney, Arie Kapteyn and Franco Peracchi, eds., Pensions:  More Information, Less Ideology.  Kluwer Academic Publishers, pp. 9-27.

Sex-ratio Bias in China and elsewhere
Many societies have a traditional bias favoring male children over female children, and the result has been a huge number of “missing females.” We’ve analyzed the consequences of these changes, the effect of possible social and economic responses, and the kinds of economic incentives that might change the bias.

Bhattacharjya, Debarun, Anant Sudarshan, Shripad Tuljapurkar, Ross Shachter, Marcus Feldman. 2008. How can economic schemes curtail the increasing sex ratio at birth in China? Demographic Research 19:1831 – 1850.

Feldman, M.W., Li Shuzhuo, Li Nan, S. Tuljapurkar, and X. Jin. 2008. Son preference, marriage, and intergenerational transfers in rural China. Chapter 6, pp. 139 - 163, in A. Gauthier, C. Chu, and S.D. Tuljapurkar (eds.), Allocating Public And Private Resources Across Generations: Riding the Age Waves 2. International Studies in Population, Vol. 3. Dordrecht, The Netherlands: Springer.

Feldman, M.W., Li, N. Li, S. Tuljapurkar, and X. Jin. 2005. Son preference, marriage, and intergenerational transfer in rural China. Pp. 232-255 in S. Bowles, H. Gintis, and M.A. Osborne (eds), Unequal Chances: Family Background and Economic Success. Princeton University Press, Princeton, N.J.

Li, S., M.W. Feldman, S. Tuljapurkar, N. Li, and X. Jin. 2002. Son preference culture, marriage type, and intergenerational transfer in rural China. (In Chinese.) Pp. 243-262 in Cai Fang et al. (eds), China Population Yearbook 2002. Research Institute of Population and Labor Economics, CASS, Beijing.

Li, N., Feldman, M.W. and Tuljapurkar, S. 2000. Sex ratio at birth and son preference. Mathematical Population Studies 8: 91-107.

Li, N., M.W. Feldman, and S. Tuljapurkar. 1999. Son preference and sex ratio at birth. (In Chinese.) Population and Economics, November 1999, pp. 19-26.

Li, N., Feldman, M.W., and Tuljapurkar, S. 1999. A demographic model with cultural transmission of son preference. (In Chinese.) Population and Economics, November 1999, pp. 27-34.

Li, N., Tuljapurkar, S. and Feldman, M.W.  1995.  High sex ratio at birth and its marital implications.  (in Chinese).  Population Science of China 1:  11-20.

Tuljapurkar, S., Li, N. and Feldman, M.W. 1995.  High sex ratios in China’s future.    Science 267:  874-876.

Demographic Transitions, Developing Countries, and Aging
Developing countries face all aspects of the demographic transition – declining fertility starting from a high level, declines in the mortality of young people, and declines in the mortality of the old. The papers below examine many aspects of these changes.

These papers analyze transitions and consequences in developing countries.

Tuljapurkar, S.  2006. Structural and Policy Consequences of Mortality and Fertility Decline, In:  Population, Resources and Development: Riding the Age Waves. Eds., Shripad Tuljapurkar, Ian Pool, Vipan Prachuabmoh. Volume 1 of  the new IUSSP series on population studies. Springer Verlag.

Li, N. and Tuljapurkar, S. 2006. A Formal Model of Age Structural Transitions, In:  Population, Resources and Development: Riding the Age Waves. Eds., Shripad Tuljapurkar, Ian Pool, Vipan Prachuabmoh. Volume 1 of the new IUSSP series on population studies. Springer Verlag.

Tuljapurkar, S.,  2002.  Demographic Forces in South Asia Through 2050:  Population, Economy, Health.  In:  M.R. Chambers, ed., South Asia in 2020:  Future Strategic Balances and Alliances (Carlisle Barracks, PA:  U.S. Army War College).

These books contain many interesting chapters, including several by Tulja’s group.

2009. Responses to Aging in Advanced Industrial States: Riding the Age Waves. Eds., Shripad Tuljapurkar, Naohiro Ogawa, Anne Gauthier. IN PRESS in the new IUSSP series on population studies. Springer Verlag.

2006. Allocating Public And Private Resources Across Generations: Riding the Age Waves 2. Eds., Anne Gauthier, Cyrus Chu, Shripad Tuljapurkar.  International Studies in Population, Vol. 3 . Dordrecht, The Netherlands: Springer.

2005. Population, Resources and Development: Riding the Age Waves 1. Eds., Shripad Tuljapurkar, Ian Pool, Vipan Prachuabmoh.  International Studies in Population, Vol. 1 . Dordrecht, The Netherlands: Springer.


Mathematical Demography (especially relevant to humans)
We work on many aspects of mathematical demography. Much of this work was developed for application to humans as in the papers listed below. But all of it, and some other bits, are relevant to other species, as described in Evolutionary Ecology and Genetics

Tuljapurkar, S., 2002.  Mathematical demography: renewal theory and stable population model.  In:  Encyclopedia of Population, Paul Demeny and Geoff McNicol (Eds)., New York: Macmillan Reference USA.

Tuljapurkar, S., 2002.  Population Biology.  In:  Encyclopedia of Population, Paul Demeny and Geoff McNicol (Eds.), New York: Macmillan Reference USA.

Tuljapurkar, S., 2001.  Formal theory of population cycles.  In:  N.J. Smelser and P. B. Baltes (editors) International Encyclopedia of the Social and Behavioral Sciences.  Pergamon, Oxford, pp. 11755-58.

Li, N. and Tuljapurkar, 1999.  Population momentum. Population Studies, 53: 255-262.

Li, N. and Tuljapurkar, 1999.  The Solution of time-dependent population models. Mathematical Population Studies, 7:  311-329.

Tuljapurkar, S. 1982.  Population dynamics in variable environments.  IV.  Weak ergodicity in the Lotka equation.  Journal of Mathematical Biology 14: 221-230.

We have shown that age-targeting makes a difference to the control of infectious disease.

Tuljapurkar, S., John, A. M. and Kalich, S.  1995.  Population growth changes targets for immunization.  Population Today 23:  5.

Tuljapurkar, S. and John, A.M.  1991.  Disease in changing populations: Growth and disequilibrium. Theoretical Population Biology 40:  322-353.

John, A.M. and Tuljapurkar, S.  1990.  Childhood infectious diseases in LDCs:  Design and evaluation using demographic-epidemiologic models.  Research Division Working Papers No. 22, The Population Council.

Population and Environment
This is a subject laden with emotion, prejudice and bias. There has been some useful writing on the broad theme. The two pieces below are “only” book reviews but are worth reading.

Tuljapurkar, S.  2004.  Book Review.   Population Matters:  Demographic Change, Economic Growth, and Poverty in the Developing World, edited by N. Birdsall, A.C. Kelley, and S.W. Sinding).  Journal of Economic Literature: June, Vol. XLII:  545-547.

Tuljapurkar, S. 1996. Book Review (How Many People Can the Earth Support? by J. E. Cohen): Contingent Answers to a Global Question.  Science 272:  696-697.