Demographics or demographic data are the characteristics of a human population as used in government, marketing or opinion research, or the demographic profiles used in such research.
Commonly used demographics include sex, race, age, income, disabilities, mobility, educational attainment, home ownership, employment status, and even location. Distributions of values within a demographic variable, and across households, are both of interest, as well as trends over time. Demographics are frequently used in economic and marketing research.
Demographic trends describe the changes in demographics in a population over time. For example, the average age of a population may increase over time. It may decrease as well. Certain restrictions may be set in place changing those numbers, for instance in China with the one child policy.
As of 5 March 2010, the Earth's human population is estimated by the United States Census Bureau to be 6,806,500,000. The United Nations estimated the world's population to be 6,800,000,000 in 2009. The fastest rates of world population growth (above 1.8%) were seen briefly during the 1950s then for a longer period during the 1960s and 1970s.
The 2008 rate of growth has almost halved since its peak of 2.2% per year, which was reached in 1963. World births have leveled off at about 134 million per year, since their peak at 163 million in the late 1990s, and are expected to remain constant.
However, deaths are only around fifty-seven million per year, and are expected to increase to ninety million by the year 2050. Because births outnumber deaths, the world's population is expected to reach nine billion in 2040, or by 2050.
The rapid increase in human population over the course of the 20th century has raised concerns about whether Earth is experiencing overpopulation. The scientific consensus is that the current population expansion and accompanying increase in usage of resources is linked to threats to the ecosystem.
Population evolution in different continents the vertical axis is logarithmic and is millions of people. From the middle of the eighteenth century Western Europe witnessed a historically unprecedented decrease in mortality, followed by a period of rising fertility and then a secular decline in fertility.
It was roughly while the western world was in the process of this momentous transformation that population became a subject of intense debate. Economists and statesmen have at different times, in different places been extremely anxious about the consequences of contemporary demographic developments.
These anxieties were largely associated with the internal contradictions of the capitalist expansion.
The dilemmas of development, then can form the purposes of this unit be schematically classified into three broad groups: Overpopulation, immigration and the demographic deformations associated with the continuing hold of older attitudes towards marriage, health and son-preference in a context of capitalist growth, finally, though less closely related to the dynamics of capitalist growth.
We have imagined demographic imbalances being attributed to certain ethnic and religious groups for reasons of ideology and political power.
Population has frequently been invoked to explain a variety of social processes-population growth as a check on outcome of poverty and so on. There clearly seems to be a lack of certainty regarding whether population is the explanatory or dependent variable.
To clarify some of these issues relating to demographic change, it would be necessary to have some rudimentary understanding of 'the larger processes on which these are premised. First, it becomes necessary to understand the demographic determinants of population change.
Next, these determinants or the most significant of these determinants need to be studied in association with the larger dynamics of economic and social change in region or country being studied.
When discussing these changes at the global level, in the modern period, these could be reduced to three large processes that have characterized would history: the rise of capitalism beginning first in north-western Europe, the increasing economic disparities between the west and the poorer countries to the world with capitalist growth and imperialist expansion and finally the rapidity of economic change in the developing world without commensurate changes in social attitudes.
Population change can be explained in demographic terms by terms by a simple equation, which demographers call the Balancing Equation:
Where it is the initial size of the population B, D, I and E denote the number of births, deaths and in-migrants (immigrants) and out-migrants (emigrants) between the two dates.
In other words, population change is the result of three variables-fertility, mortality and migration.
At different times in history, in particular regions, one or the other of these variables assumed greater significance than the others fertility, mortality and migration in turn, are determined by pure demographic factors and a larger set of social and economic variables.
The demographic change of Europe
The historical demography of Europe is important to any discussion of the demographic variable in the world context, as it was here in the eighteenth century that population first showed rapid increase followed by a sustained decline.
The population of north-west Europe increased from between 60 to 64 million in 1750 to about 116 million in 1850 growing at an annual compound rate of around 0.6%. Between the French Revolution and the 1st World War, mortality sharply declined with the availability of new resources and favorable epidemiological changes, creation condition where population could possibly increase.
The introduction of new crops such as potato and maize, greatly contributed to limiting subsistence crises and permitting population increase. Further, during the eighteenth century plague and associated epidemics such as typhus, smallpox, malaria, venereal diseases lost much of their lethal efficacy.
Population increased sharply at first but was then limited by nuptiality checks. Next it resulted in large overseas migration and a sustained decline in fertility. It led to the massive movement of Europeans overseas and also to the demographic transition. This demographic transformation is one of the most significant transformations that Europe witnessed in the last millennium.
In the 20th century Western Europe devastating wars further exacerbated the effects of fertility decline, finally resulting in an ageing age structure and growth rates that will turn negative in the future.
The demographic change of India
The population of India grew slowly from 1871 to 1921 largely because of the mortality check despite high fertility. In the post 1921 years up to the 1980s fertility remained high but mortality declined leading to rapid population growth and resulting in a very young age population. Women fared badly in terms of mortality relative to men throughout the period. The sex ratio at birth usually falls between 1040 and 1070, internationally.
In other 104 to 107 male babies are born for every 100 femalebabies. On the other hand male mortality is also generally higher than female mortality in the older age groups. Despite this, India has exhibited a continuous decrease in the proportion of women. This is explained by lower life expectancy at birth for females. This all-India trend however does not hold good for many part of India.
India's age distribution has remained remarkably stable with a large and virtually constant proportion of young people. In a closed population such as that of India's, the Large proportion of children points to high levels of fertility. The age distribution also suggests a high dependency ratio. Further, the youthfulness of the population also ensured a continued population momentum that would last beyond the onset of fertility decline.
Demographic change is thus one of the most pressing problems facing the modern world today. The problems are different, specific to societies and countries and are closely related to wider economic and social changes.
Attempt to understand demographic change without reference to time and region-specific context has failed. The relationship between development and demographic problems is so closely intermeshed, that both in the underlying processes of global economic, political and social change, is held culpable for a range of problems.