Obituary: Professor William Brass

WILLIAM BRASS was one of Britain's most distinguished population scientists since the Rev Thomas Malthus. Over a long career he almost single-handedly created a new and important strand of demography. The central problem that he addressed was this. In developing countries where most births and deaths are not recorded, how can reliable estimates be made of death rates, birth rates and trends in the size and structure of a population?

Over the last 40 years, he devised a series of ingenious answers to this question. For instance he showed how child-mortality levels and totals could be derived from simple questions in censuses or surveys to mothers on numbers of children born and still surviving; and how adult mortality could be estimated by asking people whether their father or mother had died.

He was a genius at transforming sow's ears into silk purses. The phrase "Brass estimates" has become part of the everyday vocabulary of demographers. Much of what we know about the populations of the developing world stems from the battery of methods that he devised.

Brass's work always had a strong methodological focus but the applications ranged widely. He made major contributions to the study of the bio-social determinants of fertility and mortality; population forecasting; and evaluation of family planning programmes. One of his most important studies, from a policy stance, was the demonstration that the high birth rates in the 1970s of some immigrant groups in this country would not be sustained.

Bill Brass was born in Edinburgh in 1921 and studied at Edinburgh University from 1940 to 1943 and again, after war service, from 1946 to 1947. From 1948 to 1955 he was Statistician, and later Deputy Director, in the East African Statistical Department. There he worked on the East African Medical Survey and some of the early colonial censuses and it was during this time that he developed many of his ideas on the collection of demographic data and techniques for their analysis.

In 1955 he returned to academic life in the Department of Statistics in Aberdeen University. He remained there for nine years, and was appointed Senior Lecturer in 1963. During this period, a year's leave of absence was taken at the Office of Population Research at Princeton University. From this collaboration with Ansley Coale and others emerged a monumental volume entitled The Demography of Tropical Africa (1968), which remained the definitive statement on the subject for well over a decade.

From 1965 until his retirement in September 1988, Brass worked at the London School of Hygiene and Tropical Medicine, appointed first as Reader and then awarded a personal Chair in Medical Demography in 1972. He was the school's first demographer but soon gathered round him a core of population scientists. In 1974, with support from the then Overseas Development Administration, he created a Centre for Population Studies at the school and became its first director. Subsequently, with support from the Economic and Social Research Council, the centre's work was broadened to encompass research on the demography of Britain and other developed countries. Twenty-five years later, this centre is still flourishing.

No account of Brass's contribution to his subject would be complete without mention of his teaching. He was a gifted communicator for whom teaching was a central responsibility. In 1970, he was instrumental in creating a Master's course in Medical Demography and he personally undertook a huge share of the teaching. In addition, he acted as supervisor for some 30 doctoral students, with whom he elaborated or refined many of his methods. A large proportion of senior demographers in the UK studied under him and owe him a huge debt.

During the course of his career, Brass received many recognitions of his contribution to the advancement of knowledge in the field of demography. In 1978 he received the Mindel C. Sheps Award from the Population Association of America. He was elected a Fellow of the British Academy in 1979 and appointed CBE in 1981.

In 1984 he was elected Foreign Associate of the US National Academy of Sciences, the highest honour that the academy can bestow on a foreigner. In 1985 he was elected President of the International Union for the Scientific Study of Population, a post that spanned a term of four years.

Those who achieve great scientific distinction often inspire respect, but less often affection from their colleagues and students. In this, too, Brass was exceptional. He was universally admired: for his integrity, for his kindness, for his simplicity, and for his good humour with its characteristic Scottish flavour. Those who worked with him in Africa will recall his stunning dancing of the tango with his wife, Betty. His colleagues in London will remember him as organiser and Santa Claus at the Children's Christmas party for many years. His many students will continue to wonder at his ability to convey complex ideas with straightforward, robust language.

William Brass, demographer: born Edinburgh 5 September 1921; Scientific Officer, Royal Naval Scientific Service 1943-46; Statistician, East African Statistical Department, Colonial Service 1948-53, Deputy Director 1953- 55; Lecturer in Statistics, Aberdeen University 1955-64, Senior Lecturer 1964-65; Reader in Medical Demography, London School of Hygiene and Tropical Medicine 1965-72, Director, Centre for Overseas Population Studies 1974- 78, Head, Department of Medical Statistics and Epidemiology 1977-82, Professor of Medical Demography 1972-88 (Emeritus), Director of Centre for Population Studies 1978-88, Honorary Fellow 1997; FBA 1979; CBE 1981; married 1948 Betty Topp (two daughters); died Chalfont St Peter, Buckinghamshire 11 November 1999.