Nathan Keyfitz, Andelot Professor of Sociology in the Faculty of Arts and Sciences and of Demography in the Faculty of Public Health, passed away on April 6, 2010, in Lexington, Massachusetts. He was 96 years old.

Considered the preeminent mathematical demographer of his day, Keyfitz was a pioneer in the application of mathematical methods to the study of populations. His publications, including six books and over a hundred articles, cover a wide range of topics including population theory, historical demography, mortality, urbanization, forecasting, the relationship between retirement and social security, poverty, and the interplay between populations and their environments. His research and consulting activities involved numerous countries including Indonesia, Italy, India, Russia, China, Ceylon, and Argentina.

Keyfitz was a fellow of the Royal Society of Canada, the Royal Statistical Society, the American Statistical Association, the American Academy of Arts and Sciences, and the National Academy of Sciences. He was the recipient of seven honorary doctorates, won the Mindel C. Sheps Award of the Population Association of America in 1976, and the Common Wealth Award of Distinguished Service in 1991. A symposium on mathematical demography was held at Ohio State University in his honor in June 2013.

The citation to the Mindel C. Sheps Award noted that, “Dr. Keyfitz’s original contributions have included an exposition of the momentum factor in population growth, advances in the understanding of multiple decrement tables, refinement of life table construction methods and innovations in the design and evaluation of population projections. He has enriched the field by bringing in techniques from mathematical biology and mathematics. He has been a leader, too, in the application of computer to demographic phenomena.”

Three of Keyfitz’s books were particularly influential. His Introduction to the Mathematics of Population (1968) became a foundational text for the field of mathematical demography and was the textbook for many years for courses in this field. His Applied Mathematical Demography (1977) broke new ground by showing how changes in specific factors that regulate population dynamics, such as birth and mortality rates, determine the characteristics of a population such as its age distribution. In addition, Keyfitz examined what would be the effects of eradicating specific diseases and the implementation of family planning. Keyfitz’s third major book, Population Change and Social Policy (1982), showed how demographic methods can be used to analyze a vast variety of social policy issues: the effects of birth control and abortion, the calculation of annuities from unisex life tables, where medical research should focus, needed adjustments to social security, and the effects of societal demography on innovation.

Keyfitz was born in Montreal on June 29, 1913. He earned his BS.c. degree in mathematics from McGill University in 1934 and his Ph.D. in Sociology from the University of Chicago in 1952. Keyfitz started his career as a statistician at the Dominion Bureau of Statistics in Ottawa, Canada, where he worked for more than 20 years studying dimensions of the Canadian population. Over the remainder of his professional career, he held academic appointments at the Universities of Toronto, the University of Chicago, the University of California, and Ohio State University, as well as Harvard.

Keyfitz was a professor at Harvard from 1972 to 1983 in the Department of Sociology in the Faculty of Arts and Sciences and in the Department of Population Science at the Harvard School of Public Health. He directed Harvard’s Center for Population and Development Studies from September 1973 to January 1975. He also served as chair of the Department of Sociology from 1978 to 1980.

Keyfitz became professor emeritus at Harvard and moved to Ohio State where he was the Lazarus Professorship in Population Studies. In 1983 Keyfitz joined the International Institute for Applied Systems Analysis in Vienna, Austria, first becoming its deputy director and the founding head of its demography department and later its president.

The quintessentially polite and gentlemanly Canadian, Keyfitz was known for his warm and giving spirit. He was generous with his time, always being available to students and his colleagues. He loved exploring ideas with others and taught courses with colleagues with very different methodologies and theoretical perspectives in sociology. Keyfitz was also a deeply committed family man. He adored his wife, Beatrice, and was a loving father and grandfather. He is survived by his children, Robert and Barbara, grandchildren, Benjamin, Elizabeth, and Alexander, and his sister, Ruth Karp.

Respectfully submitted,

Orlando Patterson
Mary C. Waters
Christopher Winship, Chair