Scope of Demography

CHAPTER ONE

The scope of demography
David Lucas
January 2002
Demography focuses on fertility (births), mortality (deaths), and migration (territorial movements). A glance at the Australian newspapers in December, 2001, found articles on, abortion, ageing, late childbearing and asylum seekers, all of which are of interest to demographers and to the general public. Some definitions of demography are given in Box 1.1. The term demography meaning ‘description of the people’ was first used by the Belgian statistician Achille Guillard in 1855 in his book Elements of Human Statistics and Comparative Demography (see Pressat 1985:54). To a statistician a population can be any collection of items but to a demographer it means a collection of people. Preston et al (2001:1) describe two such collections: • A population of persons alive at a particular point in time. For example, the 2001 Australian census collected information on all people in Australia on the night of Tuesday, August 7 th of August, 2001. • A population that ‘persists through time even though its members are continuously changing’. Demographers may thus talk about the aggregate of persons who have ever lived in Australia in the past and also about people in Australia in the future. Populations can be subdivided, often by age and sex. For example, a study of the Australian labour force may look at males and females aged from 15 to 64 years. In a more restricted sense, a population can refer to any group being studied where its size and structure depend on persons entering and leaving (Pressat 1985:176). The composition of the Australian Defence Force largely depends on the entry of recruits and on members exiting on resignation (Schindlmayr and Ong, 2001). The components affecting population change are measured by birth, death and migration rates that determine the numbers in the population, its age composition, and how fast it is growing or declining. If demographers are studying a country they will ask such basic questions as: How many males and females are there now? Where are they? What are their ages? How many births have occurred, and to whom? What are the characteristics of those who die or migrate? How and why will these change?

1

BEGINNING AUSTRALIAN POPULATION STUDIES

BOX 1.1 Defining demography • Demography is the study of human populations in relation to the changes brought about by the interplay of births, deaths, and migration. The term is also used to refer to the actual phenomena observed, as in phrases such as the demography of tropical Africa (Pressat 1985:54). Demography is the statistical and mathematical study of the size, composition, and spatial distribution of human populations, and of changes over time in these aspects through the operation of the five processes of fertility, mortality, marriage, migration, and social mobility. Although it maintains a continuous descriptive and comparative analysis of trends, in each of these processes and in their net result, its long-run goal is to develop a body of theory to explain the events that it charts and compares (Bogue 1969: 1-2). Demography is the study of the size, territorial distribution, and the composition of population, changes therein, and the components of such changes, which may be identified as natality, mortality, territorial movement (migration), and social mobility (change of status) (Hauser and Duncan 1959:2).

•

•

Note: In this last definition Hauser and Duncan (1959:2) explain that the omission of population quality is deliberate. Population composition refers not only to characteristics such as age, sex, and marital status but also to health and occupation. Social mobility involves changes in status e.g. through marriage and migration. The inclusion of social mobility as a part of demography can be disputed. Bogue (1969:28) includes it because ‘ there is very strong demographic component in this line of research’.

John Graunt, who lived from 1620 to 1674, answered some questions of this kind for 17th century London. He estimated that London’s population comprised 199,000 males and 185,000 females, and that slightly more males than females had been born between 1628 and 1662 (Graunt 1975:57). Graunt was a cloth seller, and his knowledge of ‘shop arithmetic’ was the basis for his 1662 Natural and Political Observations, a study of births and deaths. His data were presented in statistical tables, their reliability was assessed and adjustments made (Kreager 1988). Because he calculated demographic rates and other statistics, Graunt is often called ‘the father of demography’. In Australia pioneering effforts in demography included Pell’s 1867 paper on mortality rates (reproduced in Santow et al 1988) and the work of the first two Commonwealth Statisticians, Knibbs and Wickens (Gray 1998). Knibbs’s Mathematical Theory of Population, published in 1917, included estimates of the world’s population, as well as of the carrying capacity and optimum population of Australia (Santow et al. 1988:163).

2

THE SCOPE OF DEMOGRAPHY

FORMAL DEMOGRAPHY AND RATES Formal demography includes the collection and statistical analysis of demographic data. Formal demographers are often mathematicians or statisticians who deal with demographic variables in a mathematical way. For example, if the number of women of childbearing age is changing, what are the possible effects on the birth rate in the future? Demographic analysis often focuses on aggregates such as changes in the size, growth rates and composition of populations. Demography also looks at the demographic circumstances faced by an average individual, with indexes such as life expectancy and total fertility, and the consequences of changes in individual or micro-level behaviour on the aggregate or macro-level (Preston et al 2001:1). When demographers work with rates, they are usually concerned with large numbers. This point will become clearer when the calculation of some rates is described. When demographers talk about rates they often mean a special kind of ratio which expresses what happens in a unit of time (usually one year). Crude rates are the simplest and least informative, and they show the relationship between vital events (such as births and deaths) and the total population. The crude birth rate (CBR) for a given year is the annual number of births (B) for that year divided by the total mid-year population (P). For convenience, births are expressed per thousand persons. B (CBR = P x 1,000) The crude death rate (CDR) is the annual number of deaths (D) per thousand persons. D (CDR = P x 1,000) The crude rate of natural increase is the difference between the crude birth rate and the crude death rate. Since births normally exceed deaths, natural increase is usually positive. While birth and death rates usually are shown per thousand of the population, the rate of natural increase is usually expressed as a percentage. A rate of natural increase of 18 per thousand is expressed as 1.8%. The third component of population growth, migration, must be taken into account before a growth rate can be calculated. If international migration is zero or negligible, then the growth rate for a country or region will be the same as the crude rate of natural increase.

3

BEGINNING AUSTRALIAN POPULATION STUDIES

The balancing equation shows how a population changes over time. In its simplest form the population in, say, the year 2000 will equal the population in 1990 plus the natural increase (births minus deaths) in the period plus or minus net migration.
Table 1.1 Crude rates, 1995-2000 Crude birth rate (per 1000) Crude death rate of (per 1000) Crude rate natural increase (per 1000) 1 13 12 Annual growth rate (%)

More developed regions Less developed regions World

11 24 21

10 11 9

0.1 1.3 1.2

Source: United Nations 2000:39, 67.

Overall the developing countries have higher birth and growth rates than the developed countries, as is shown in the estimates for the period 1995-2000 (Table 1.1). The rate of increase in the less developed countries is much larger than in the developed countries. The causes and effects of these differences are among the major concerns of formal demographers and other population scientists. POPULATION STUDIES Population Studies is more interdisciplinary than formal demography and draws on the social and biological sciences. Many demographers prefer the population studies approach in which the relationship between demographic and non-demographic variables is considered. They are interested in the effect of a non-demographic variable on a demographic variable: for example, how changes in income or education can affect fertility or mortality. Some demographers are interested in the reverse process, where a demographic variable causes a change in the non-demographic variable. However, this is more properly the concern of people in other disciplines. For instance, if a population has an increasing proportion of old people, voting patterns may change, perhaps because older people prefer the more traditional political party. This is a topic to be studied by the political scientist, not the demographer.

4

THE SCOPE OF DEMOGRAPHY

As an example of how demography and population studies are related to other disciplines, consider the study of the family. Demographers are interested in the family because demographic events affect its size and composition. The historian, and especially the historical demographer, may be concerned with the family in the past, with the age of marriage and the composition and size of households in earlier times. Since the family is a basic unit of social activity, the sociologist and anthropologist are also interested: in the status, roles and decision-making of family members (see Caldwell and Hill 1988; Hawthorn 1970; Nag 1973). In some societies, having many children gives prestige to the mother and to the family. Why people want children is a question that may concern the psychologist (see East-West Population Institute 1976). Economists look at the family as an economic unit, and their studies cover items such as the financial costs of children that are also relevant to the demographer’s work. A more specific example is the link between demography and epidemiology. Both words are derived from the Greek demos (the people). An epidemic occurs when a disease attacks a large number of people at the same time. Epidemiology, however, is more than the study of epidemics, it now covers morbidity (the investigation of illness and disease) and one of its consequences, mortality. Woods (1982 cited in Jones 1990) considers that the primary objective of population geography is to provide the spatial perspective to the wider field of population studies. Developments in demography that enhance population geography include the incorporation of community studies, the use of ‘territorially disaggregated data’ and a greater appreciation of structural change (Jones 1990:7) Technical advances include Geographical Information Systems (GIS) pioneered by the US Bureau of the Census in the 1980s (see Demoz, June 2000:14-15). A WIDENING FIELD The field of demographics, or applied demography grew in the 1980s. Demographics is concerned with ‘the use of existing knowledge and techniques to identify and solve problems.’ (Weeks 1992:477). Major uses of demographics include: • Marketing and consumer trends (The magazine American Demographics focuses on this use). • Social planning (for example planning for future school enrollments). • Human resources. For example Schindlmayr and Ong (2001) examine Australian demographic and socio-economic trends and how they can affect human resource policies of the Australian Defence Force. Demography broadened its scope further as a result of the International Conference on Population and Development, held in Cairo in September, 1994. In Cairo more than 180 States prepared a Programme of Action linking population and development over the next twenty years (United Nations 1998:iii).

5

BEGINNING AUSTRALIAN POPULATION STUDIES

The Programme defined reproductive health as a state of complete physical and mental and social well-being that included: • The freedom of couples to reproduce when they wanted. • The right to be informed of, and have access to family planning. • The right of access to health-care service before and after pregnancy. The Programme reflected many of the concepts of the past decade including sustainable development and investment in human resources. It advocated ‘safe motherhood’ and ‘the empowerment of women’, including the access of women to education beyond primary school (United Nations 1995: 1-7). More on the implementation of the Programme of Action can be found in McMurray and Lucas (1998). DEMOGRAPHERS AND JOBS Demographers are often multi-skilled, particularly if they gained their first degrees in subjects such as geography, statistics or health, and have then studied demography at the graduate level. Training in demography will normally provide them with skills in computing and statistical analysis as well as insights into population and health programmes and policies. Students of demography thus find employment in a wide range of professional settings. In the public sector, demographers are employed in: • Government statistical offices, especially in the sections dealing with censuses, surveys, and registration data. • National, state, and local planning bodies, especially in educational and health planning, housing, and social policy. • Government research units in areas such as immigration and labour market analysis. • In development cooperation agencies such as AusAID and USAID. Demographers can also be found in university research units and private consulting firms. Many international agencies, such as the United Nations Population Division and United Nations Fund for Population, and non-government organisations also utilize the skills of demographers. In the private sector demographic analysis is recognized as a vital part of market research and investment planning.

6

THE SCOPE OF DEMOGRAPHY

REFERENCES Bogue, Donald, 1969. Principles of Demography, Wiley, New York. Caldwell, John and Hill, Alan, 1988. ‘Recent developments using micro-approaches to demographic research’, in J. Caldwell, A. Hill and V. Hull (eds), Micro-Approaches to Demographic Research, Kegan Paul, London: 1-9. East-West Population Institute, 1976. Teaching Population Psychology, Honolulu. Graunt, John, 1975. Natural and Political Observations Mentioned in a Following Index and Made upon the Bill of Mortality, Arno Press, New York. Gray, Alan, 1988. ‘Knibbs and Wickens’, Journal of the Australian Population Association, 5(1):1-14. Hauser, P. and Duncan, O. (eds), 1959. The Study of Population, University of Chicago, Chicago. Hawthorn, Geoffrey, 1970. The Sociology of Fertility, Collier-Macmillan, London. Jones, Huw, 1990. Population Geography, Paul Chapman, London. Kreager, Philip, 1988. ‘New light on Graunt’, Population Studies, 42(1):129-40. McMurray, Christine, and Lucas, David, 1998. Briefing Pack on Population and Development, Australian Reproductive Health Alliance, Canberra. (http://www.arha.org.au/BriefingFrameset.htm) Nag, Moni, 1973. ‘Anthropology and population: problems and perspectives’, Population Studies, 27(1):59-68. Pressat, Roland, 1985. The Dictionary of Demography, (English edition C. Wilson (ed.)), Blackwell, Oxford. Preston, Samuel, Heuveline, Patrick, and Guillot, Michel, 2001. Demography, Blackwell, Oxford. Santow, Gigi, Borrie, W.D. and Ruzicka, L., (eds.), 1988. Landmarks in Australian Population Studies, Supplement to Journal of the Australian Population Association, 5. Schindlmayr, Thomas, and Ong, Peter, 2001. Defence Personnel Environmental Scan 2020, Defence Publishing Services, Canberra. (http://www.defence.gov.au/dpe/dpe_site/publications/Environment_Scan_ 2020.pdf) United Nations, 1995. Population Consensus at Cairo, Mexico City and Bucharest , United Nations, New York. ---------- ---------- 1998, Programme of Action, United Nations, New York. ---------- ---------- 2000. World Population Prospects, United Nations, New York. Weeks, John, 1992. Population, Wadsworth, Belmont, California.

7

References: Bogue, Donald, 1969. Principles of Demography, Wiley, New York. Caldwell, John and Hill, Alan, 1988. ‘Recent developments using micro-approaches to demographic research’, in J. Caldwell, A. Hill and V. Hull (eds), Micro-Approaches to Demographic Research, Kegan Paul, London: 1-9. East-West Population Institute, 1976. Teaching Population Psychology, Honolulu. Graunt, John, 1975. Natural and Political Observations Mentioned in a Following Index and Made upon the Bill of Mortality, Arno Press, New York. Gray, Alan, 1988. ‘Knibbs and Wickens’, Journal of the Australian Population Association, 5(1):1-14. Hauser, P. and Duncan, O. (eds), 1959. The Study of Population, University of Chicago, Chicago. Hawthorn, Geoffrey, 1970. The Sociology of Fertility, Collier-Macmillan, London. Jones, Huw, 1990. Population Geography, Paul Chapman, London. Kreager, Philip, 1988. ‘New light on Graunt’, Population Studies, 42(1):129-40. McMurray, Christine, and Lucas, David, 1998. Briefing Pack on Population and Development, Australian Reproductive Health Alliance, Canberra. (http://www.arha.org.au/BriefingFrameset.htm) Nag, Moni, 1973. ‘Anthropology and population: problems and perspectives’, Population Studies, 27(1):59-68. Pressat, Roland, 1985. The Dictionary of Demography, (English edition C. Wilson (ed.)), Blackwell, Oxford. Preston, Samuel, Heuveline, Patrick, and Guillot, Michel, 2001. Demography, Blackwell, Oxford. Santow, Gigi, Borrie, W.D. and Ruzicka, L., (eds.), 1988. Landmarks in Australian Population Studies, Supplement to Journal of the Australian Population Association, 5. Schindlmayr, Thomas, and Ong, Peter, 2001. Defence Personnel Environmental Scan 2020, Defence Publishing Services, Canberra. (http://www.defence.gov.au/dpe/dpe_site/publications/Environment_Scan_ 2020.pdf) United Nations, 1995. Population Consensus at Cairo, Mexico City and Bucharest , United Nations, New York. ---------- ---------- 1998, Programme of Action, United Nations, New York. ---------- ---------- 2000. World Population Prospects, United Nations, New York. Weeks, John, 1992. Population, Wadsworth, Belmont, California. 7