Demography is the statistical study of human populations. The study of statistics such as income, deaths, births, incidence of disease, marriages, migration, all form part of the general science of demography. It mainly focuses on data that illustrates the changing structure of human populations.
The term may also refer to a specific structure of a human population, as in “The demography of the United States is changing,” (the makeup of its people is changing).
A population specialist is called a demographer. He or she analyses any kind of dynamic living population – one that changes over space or time.
Demographers focus on three main processes that affect populations: Births, Ageing/Deaths, and Migration.
Demography includes the study of the size, distribution, and structure of specific populations, as well as temporal or spatial changes in them in response to births, deaths, ageing and migration.
Demographics are the quantifiable features (characteristics) of a given population – the statistical data related to a population or groups within it.
According to BusinessDictionary.com, demography is:
“Study of both quantitative and qualitative aspects of human population. Quantitative aspects include composition, density, distribution, growth, movement, size, and structure of the population.”
“Qualitative aspects are the sociological factors such as education quality, crime, development, diet and nutrition, race, social class, wealth, well being.”
Ban Ki-moon (潘基文), Secretary-General of the United Nations, once said: “Grave security concerns can arise as a result of demographic trends, chronic poverty, economic inequality, environmental degradation, pandemic diseases, organized crime, repressive governance and other developments no state can control alone. Arms can’t address such concerns.” (Image: Wikipedia)
History of demography
Demography and demographic thoughts have been around for many thousands of years. It was extensively discussed in the civilizations of Ancient Rome, Ancient Greece, India and China.
In Ancient Greece, this can be found in the works of Epicurus, Hippocrates, Thucidides, Herodotus, Polus, Protagoras and Aristotle. Among the Roman writers, Cato, Collumella, Epictetus, Marcus Aurelius, Cicero and Pliny the Elder all expressed important ideas regarding demography.
Christian thinkers in the Middle Ages devoted much of their time refuting the Classical ideas on demography.
In 1662, John Graunt (1620-1674), one of the first population specialists, though by profession he was a haberdasher, wrote Natural & Political Observations Made upon the Bills of Mortality. His work contained a primitive form of life table. He reported that one-third of all London’s children died before reaching the age of sixteen.
Edmond Halley (1656-1742), an English astronomer, mathematician, geophysicist and physicist, after whom the famous ‘Halley Comet’ is named, created a life table as the basis for life insurance mathematics.
The first textbook on life contingencies was written by Richard Price (1723-1792), a Welsh moral philosopher, preacher and mathematician, and published in 1771. His publication was followed in 1838 by Augustus de Morgan’s work ‘On the Application of Probabilities to Life Contingencies’.
A ‘Demographics of the World’ map may focus on people’s incomes, religions, longevity, age groups, children per female, etc. In this image, the demographics shown are the dominant religions. (Image: Wikipedia)
At the end of the 18th century, Thomas Robert Malthus FRS (1766-1834), an English cleric and scholar, influential in the fields of political economy and demography, concluded that populations would be subject to exponential growth if left unchecked. He was concerned that populations would grow faster than the growth in food production, leading to widespread famine and worsening poverty.
From 1980 to 1910, demography emerged from statistics as a separate field of interest. The field evolved rapidly, thanks to a number of mathematicians and scholars.
The term was first used by the Belgian statistician Achille Guillard (1799-1876) in his 1855 publication: Elements de statistique humaine, ou demographie comparee.
Three main processes
According to the Max Planck Institute for Demographic Research in Germany, demography is the study of populations – the science of populations. Demographers aim to understand population dynamics by investigating three principal processes: 1. Births. 2. Migration. 3. Ageing (including death).
Each of these processes contributes to changes in populations, including how humans inhabit our planet, from nations and societies, and develop culture.
While most of demography’s research focuses on human beings, it also includes the specialized field of biodemography. Biodemography is an interdisciplinary approach to demography in which genetic, evolutionary, epidemiological determinants – biological considerations – are emphasized.
Population dynamics and features have become popular subjects among lay people. Politicians, sociologists and economists love talking about ‘demographic change’, especially in the advanced economies.
Birth rates in the rich nations have fallen below the 2.1 children per woman replacement level, life expectancy has been rising steadily and will continue to do so – a development sometimes referred to as ‘the aging of societies’.
Demography only reports on what conditions are, have been or will be like – it cannot offer political advice on how to tackle population issues. Demographers may help by determining what the causes are.
“Using reliable data and the statistical processing of these data, modern demographic research embraces many scientific disciplines, including mathematics, economics and other social sciences, geography or biology.”
Video – What is demography?
This video explains what demography is – the study of human populations – and what demographers do.