Demographic transition (DT) refers to the transition from high birth and death rates to low birth and death rates as a country develops from a pre-industrial to an industrialized economic system. This is typically demonstrated through a demographic transition model (DTM). The theory is based on an interpretation of demographic history developed in 1929 by the American demographer Warren Thompson (1887–1973). Thompson observed changes, or transitions, in birth and death rates in industrialized societies over the previous 200 years. Most developed countries are in stage 3 or 4 of the model; the majority of developing countries have reached stage 2 or stage 3. The major (relative) exceptions are some poor countries, mainly in sub-Saharan Africa and some Middle Eastern countries, which are poor or affected by government policy or civil strife, notably Pakistan, Palestinian Territories, Yemen and Afghanistan.
Although this model predicts ever decreasing fertility rates, recent data show that beyond a certain level of development fertility rates increase again.
Demographic economics or population economics is the application of economic analysis to demography, the study of human populations, including size, growth, density, distribution, and vital statistics.
Aspects of the subject include
Human geography is one of the two major sub-fields of the discipline of geography. Human geography is a branch of the social sciences that studies the world, its people, communities and cultures with an emphasis on relations of and across space and place. Human geography differs from physical geography mainly in that it has a greater focus on studying human activities and is more receptive to qualitative research methodologies. As a discipline, human geography is particularly diverse with respect to its methods and theoretical approaches to study.
According to the Encyclopedia of International Development, the term demographic trap is used by demographers "to describe the combination of high fertility (birth rates) and declining mortality (death rates) in developing countries, resulting in a period of high population growth rate (PGR)." High fertility combined with declining mortality happens when a developing country moves through the demographic transition of becoming developed.
During "stage 2" of the demographic transition, quality of health care improves and death rates fall, but birth rates still remain high, resulting in a period of high population growth. The term "demographic trap" is used by some demographers to describe a situation where stage 2 persists because "falling living standards reinforce the prevailing high fertility, which in turn reinforces the decline in living standards." This results in more poverty, where people rely on more children to provide them with economic security. Social scientist John Avery explains that this results because the high birth rates and low death rates "lead to population growth so rapid that the development that could have slowed population is impossible."
The birth rate is the total number of births per 1000 of a population each year. The rate of births in a population is calculated in several ways: live births from a universal registration system for births, deaths, and marriages; population counts from a census, and estimation through specialized demographic techniques. The birth rate (along with mortality and migration rate) are used to calculate population growth.
The crude birth rate is the number of births per 1,000 people per year. Another term used interchangeably with birth rate is natality. When the crude death rate is subtracted from the crude birth rate, the result is the rate of natural increase (RNI). This is equal to the rate of population change (excluding migration).
A social issue (also called a social problem or a social situation) is an issue that relates to society's perception of a person's personal lives. Different cultures have different perceptions and what may be "normal" behavior in one society may be a significant social issue in another society. Social issues are distinguished from economic issues. Some issues have both social and economic aspects, such as immigration. There are also issues that don't fall into either category, such as wars.
Thomas Paine, in Rights of Man and Common Sense, addresses man's duty to "allow the same rights to others as we allow ourselves". The failure to do so causes the birth of a social issue.