Map of countries by population

Population growth showing projections for later this century

Demography is the statistical study of all populations. In Political geography and International politics, a country is a Political division of a geographical entity In Biology a population is the collection of inter-breeding organisms of a particular Species; in Sociology It can be a very general science that can be applied to any kind of dynamic population, that is, one that changes over time or space (see population dynamics). Population dynamics is the study of marginal and long-term changes in the numbers individual weights and age composition of individuals in one or several Populations and It encompasses the study of the size, structure and distribution of populations, and spatial and/or temporal changes in them in response to birth, death, migration and aging. Birth is the act or process of bearing or bringing forth Offspring. Death is the termination of the biological functions that define living Organisms It refers both to a specific Human migration denotes any movement by Humans from one locality to another sometimes over long distances or Ageing or aging (American English is the accumulation of changes in an organism

Human demography is the most well known discipline of demography, and typically what people refer to when using the term demography. Demographic analysis can be applied to whole societies or to groups defined by criteria such as education, nationality, religion and ethnicity. Demographic analysis includes the sets of methods that allow us to measure the dimensions and dynamics of populations Education encompasses both the Teaching and Learning of Knowledge, proper conduct, and technical competency Nationality is a relationship between a Person and their State of Origin, Culture, association Affiliation and/or Loyalty A religion is a set of Tenets and practices often centered upon specific Supernatural and moral claims about Reality, the Cosmos In academia, demography is often regarded as a branch of either anthropology, economics, or sociology. Anthropology (/ˌænθɹəˈpɒlədʒi/ from Greek grc ἄνθρωπος anthrōpos, "human" -λογία -logia) is the study of Economics is the social science that studies the production distribution, and consumption of goods and services. Sociology (from Latin: socius "companion" and the suffix -ology "the study of" from Greek λόγος lógos "knowledge" Formal demography limits its object of study to the measurement of populations processes, while the more broad field of social demography population studies also analyze the relationships between economic, social, cultural and biological processes influencing a population. ^[1]

The term demographics is often used erroneously for demography, but refers rather to selected population characteristics as used in government, marketing or opinion research, or the demographic profiles used in such research. Demographics or demographic data refers to selected population characteristics as used in government Marketing or opinion research or the Demographic profiles In popular usage "marketing" is the promotion of products especially Advertising and Branding However in professional usage the term has a wider meaning of A demographic or demographic profile is a term used in Marketing and Broadcasting, to describe a demographic grouping or a Market

Data and methods

There are two methods of data collection: direct and indirect. Direct data come from vital statistics registries that track all births and deaths as well as certain changes in legal status such as marriage, divorce, and migration (registration of place of residence). In developed countries with good registration systems (such as the United States and much of Europe), registry statistics are the best method for estimating the number of births and deaths.

The census is the other common direct method of collecting demographic data. A census is the procedure of acquiring information about every member of a given population A census is usually conducted by a national government and attempts to enumerate every person in a country. However, in contrast to vital statistics data, which are typically collected continuously and summarized on an annual basis, censuses typically occur only every 10 years or so, and thus are not usually the best source of data on births and deaths. Analyses are conducted after a census to estimate how much over or undercounting took place. Censuses do more than just count people. They typically collect information about families or households, as well as about such individual characteristics as age, sex, marital status, literacy/education, employment status and occupation, and geographical location. They may also collect data on migration (or place of birth or of previous residence), language, religion, nationality (or ethnicity or race), and citizenship. In countries in which the vital registration system may be incomplete, the censuses are also used as a direct source of information about fertility and mortality; for example the censuses of the People's Republic of China gather information on births and deaths that occurred in the 18 months immediately preceding the census.

Indirect methods of data collections are required in countries where full data are not available, such as is the case in much of the developing world. One of these techniques is the sister method, where survey researchers ask women how many of their sisters have died or had children and at what age. With these surveys, researchers can then indirectly estimate birth or death rates for the entire population. Other indirect methods include asking people about siblings, parents, and children.

There are a variety of demographic methods for modeling population processes. They include models of mortality (including the life table, Gompertz models, hazards models, Cox proportional hazards models, multiple decrement life tables, Brass relational logits), fertility (Hernes model, Coale-Trussell models, parity progression ratios), marriage (Singulate Mean at Marriage, Page model), disability (Sullivan's method, multistate life tables), population projections (Lee Carter, the Leslie Matrix), and population momentum (Keyfitz). In Actuarial science, a life table (also called a mortality table or actuarial table) is a table which shows for a person at each age what the probability A Gompertz curve or Gompertz function, named after Benjamin Gompertz, is a Sigmoid function. General Proportional hazards models are a sub-class of survival models in statistics General Proportional hazards models are a sub-class of survival models in statistics Decrement tables, also called life table methods, are used to calculate the probability of certain events Fertility is the natural capability of giving life As a measure "Fertility Rate" is the number of children born per couple person or population Ansley Johnson Coale (1917-2002 was one of America's foremost Demographers A native of Baltimore, Maryland, he earned his B The Leslie Matrix is a discrete, Age-structured model of Population growth that is very popular in Population ecology. Population momentum is an effect which causes Population growth.

Important concepts

Important concepts in demography include:

• The crude birth rate, the annual number of live births per 1000 people. Crude birth rate is the natality or Childbirths per 1000 people per year
• The general fertility rate, the annual number of live births per 1000 women of childbearing age (often taken to be from 15 to 49 years old, but sometimes from 15 to 44).
• age-specific fertility rates, the annual number of live births per 1000 women in particular age groups (usually age 15-19, 20-24 etc. )
• The crude death rate, the annual number of deaths per 1000 people. Mortality rate is a measure of the number of Deaths (in general or due to a specific cause in some population scaled to the size of that population per unit time
• The infant mortality rate, the annual number of deaths of children less than 1 year old per 1000 live births. Infant mortality is defined as the number of deaths of Infants (one year of age or younger per 1000 live births
• The expectation of life (or life expectancy), the number of years which an individual at a given age could expect to live at present mortality levels. Life expectancy is the average number of years of life remaining at a given age
• The total fertility rate, the number of live births per woman completing her reproductive life, if her childbearing at each age reflected current age-specific fertility rates. The total fertility rate ( TFR, sometimes also called the fertility rate, period total fertility rate (PTFR or total
• The gross reproduction rate, the number of daughters who would be born to a woman completing her reproductive life at current age-specific fertility rates.
• The net reproduction ratio is the expected number of daughters, per newborn prospective mother, who may or may not survive to and through the ages of childbearing.

Note that the crude death rate as defined above and applied to a whole population can give a misleading impression. For example, the number of deaths per 1000 people can be higher for developed nations than in less-developed countries, despite standards of health being better in developed countries. This is because developed countries have relatively more older people, who are more likely to die in a given year, so that the overall mortality rate can be higher even if the mortality rate at any given age is lower. A more complete picture of mortality is given by a life table which summarises mortality separately at each age. In Actuarial science, a life table (also called a mortality table or actuarial table) is a table which shows for a person at each age what the probability A life table is necessary to give a good estimate of life expectancy.

The fertility rates can also give a misleading impression that a population is growing faster than it in fact is, because measurement of fertility rates only involves the reproductive rate of women, and does not adjust for the sex ratio. For example, if a population has a total fertility rate of 4. 0 but the sex ratio is 66/34 (twice as many men as women), this population is actually growing at a slower natural increase rate than would a population having a fertility rate of 3. 0 and a sex ratio of 50/50. This distortion is greatest in India and Myanmar, and is present in China as well. India, officially the Republic of India (भारत गणराज्य inc-Latn Bhārat Gaṇarājya; see also other Indian languages) is a country Burma, officially the Union of Myanmar ( pjìdàunzṵ mjàmmà nàinŋàndɔ̀ is the largest country by geographical area in mainland Southeast Asia. China ( Wade-Giles ( Mandarin) Chung¹kuo² is a cultural region, an ancient Civilization, and depending on perspective a National

Basic demographic equation

Suppose that a country (or other entity) contains Population_t persons at time t. What is the size of the population at time t + 1 ?

Population_{t + 1} = Population_t + Naturalincrease_t + Netmigration_t

Natural increase from time t to t + 1:

Naturalincrease_t = Births_t − Deaths_t

Net migration from time t to t + 1:

Netmigration_t = Immigration_t − Emigration_t

This basic equation can also be applied to subpopulations. For example, the population size of ethnic groups or nationalities within a given society or country is subject to the same sources of change. However, when dealing with ethnic groups, "net migration" might have to be subdivided into physical migration and ethnic reidentification (assimilation). A region or society where several different groups are spontaneously assimilated is sometimes referred to as a Melting pot. Individuals who change their ethnic self-labels or whose ethnic classification in government statistics changes over time may be thought of as migrating or moving from one population subcategory to another. ^[2]

More generally, while the basic demographic equation holds true by definition, in practice the recording and counting of events (births, deaths, immigration, emigration) and the enumeration of the total population size are subject to error. So allowance needs to be made for error in the underlying statistics when any accounting of population size or change is made.

History

Ibn Khaldun (1332-1406) is regarded as the "father of demography" for his economic analysis of social organization which produced the first scientific and theoretical work on population, development, and group dynamics. Ibn Khaldūn or Ibn Khaldoun (full name أبو زيد عبد الرحمن بن محمد بن خلدون,, ( May 27, 1332 AD/732 AH &ndash March 19 Economics is the social science that studies the production distribution, and consumption of goods and services. Sociology (from Latin: socius "companion" and the suffix -ology "the study of" from Greek λόγος lógos "knowledge" His Muqaddimah also laid the groundwork for his observation of the role of state, communication and propaganda in history. The Muqaddimah, or the Muqaddimah of Ibn Khaldun ( Arabic: ar مقدّمة ابن خلدون Amazigh: Tazwarit n Ibn Xldun A state is a political association with effective Sovereignty over a geographic Area and representing a Population. Communication is the process of conveying information from a sender to a receiver with the use of a medium in which the communicated information is understood the same way Propaganda is a concerted set of messages aimed at influencing the opinions or behaviors of large numbers of people History is the study of the past particularly the written record Those who study history as a Profession are called Historians Etymology ^[3]

The Natural and Political Observations . . . upon the Bills of Mortality (1662) of John Graunt contains a primitive form of life table. John Graunt ( April 24, 1620 - April 18, 1674) was one of the first Demographers though by profession he was a Haberdasher In Actuarial science, a life table (also called a mortality table or actuarial table) is a table which shows for a person at each age what the probability Mathematicians, such as Edmond Halley, developed the life table as the basis for life insurance mathematics. Edmond Halley FRS (ˈɛdmənd ˈhɔːlɪ ( November 8, 1656 &ndash January 14, 1742) was an English Astronomer Richard Price was credited with the first textbook on life contingencies published in 1771,^[4] followed later by Augustus de Morgan, ‘On the Application of Probabilities to Life Contingencies’, (1838). Richard Price ( February 23, 1723 &ndash April 19, 1791) was a Welsh moral and political philosopher Augustus De Morgan ( 27 June, 1806 &ndash 18 March, 1871) was a British Mathematician and Logician. ^[5]

At the end of the 18th century, Thomas Malthus concluded that, if unchecked, populations would be subject to exponential growth. Thomas Robert Malthus FRS (13 February 1766 – 23 December 1834 was an English political economist and demographer who expressed views Exponential growth (including Exponential decay) occurs when the growth rate of a mathematical function is proportional to the function's current value He feared that population growth would tend to outstrip growth in food production, leading to ever increasing famine and poverty (see Malthusian catastrophe); he is seen as the intellectual father of ideas of overpopulation and the limits to growth. A Malthusian catastrophe (or Malthusian check, crisis, dilemma, disaster, trap, controls, or limit) is a return Overpopulation refers to a condition where an Organism 's numbers exceed the Carrying capacity of its Habitat. Later more sophisticated and realistic models were presented by e. g. Benjamin Gompertz and Verhulst. Benjamin Gompertz ( March 5, 1779 - July 14, 1865, London, England) was a self educated Mathematician Pierre François Verhulst ( October 28, 1804, Brussels, Belgium &ndash February 15, 1849, Brussels, Belgium

The demographic transition

World population from 500CE to 2150, based on UN 2004 projections (red, orange, green) and US Census Bureau historical estimates (black). Only the section in blue is from reliable counts, not estimates or projections.

Main article: Demographic transition

Contrary to Malthus' predictions and in line with his thoughts on moral restraint, natural population growth in most developed countries has diminished to close to zero, without being held in check by famine or lack of resources, as people in developed nations have shown a tendency to have fewer children. The Demographic transition model (DTM is a model used to explain the process of shift from high Birth rates and high Death rates to low birth rates and low death rates The fall in population growth has occurred despite large rises in life expectancy in these countries. This pattern of population growth, with slow (or no) growth in pre-industrial societies, followed by fast growth as the society develops and industrialises, followed by slow growth again as it becomes more affluent, is known as the demographic transition. Pre-industrial society refers to specific social attributes and forms of political and cultural organization that were prevalent before the advent of the Industrial Revolution The Demographic transition model (DTM is a model used to explain the process of shift from high Birth rates and high Death rates to low birth rates and low death rates

Similar trends are now becoming visible in ever more developing countries, so that far from spiralling out of control, world population growth is expected to slow markedly in the next century, coming to an eventual standstill or even declining. The change is likely to be accompanied by major shifts in the proportion of world population in particular regions. The United Nations Population Division expects the absolute number of infants and toddlers in the world to begin to fall by 2015, and the number of children under 15 by 2025. The United Nations ( UN) is an International organization whose stated aims are to facilitate cooperation in International law, International security The figure in this section shows the latest (2004) UN projections of world population out to the year 2150 (red = high, orange = medium, green = low). The UN "medium" projection shows world population reaching an approximate equilibrium at 9 billion by 2075. Working independently, demographers at the International Institute for Applied Systems Analysis in Austria expect world population to peak at 9 billion by 2070. The International Institute for Applied Systems Analysis (IIASA is an international non-governmental research organization located in Laxenburg, near Vienna, in Throughout the 21st century, the average age of the population is likely to continue to rise.

The science of population

Populations change through three processes: fertility, mortality, and migration. Fertility involves the number of children that women have and is to be contrasted with fecundity (a woman's childbearing potential). ^[6] Mortality is the study of the causes, consequences, and measurement of processes affecting death to members of the population. Demographers most commonly study mortality using the Life Table, a statistical device which provides information about the mortality conditions (most notably the life expectancy) in the population. In Actuarial science, a life table (also called a mortality table or actuarial table) is a table which shows for a person at each age what the probability ^[7] Migration refers to the movement of persons from an origin place to a destination place across some pre-defined, political boundary. Migration researchers do not designate movements 'migrations' unless they are somewhat permanent. Thus demographers do not consider tourists and travelers to be migrating. While demographers who study migration typically do so through census data on place of residence, indirect sources of data including tax forms and labor force surveys are also important. ^[8]

Demography is today widely taught in many universities across the world, attracting students with initial training in social sciences, statistics or health studies. Being at the crossroads of several disciplines such as geography, economics, sociology or epidemiology, demography offers tools to approach a large range of population issues by combining a more technical quantitative approach that represents the core of the discipline with many other methods borrowed from social or other sciences. Geography (from Greek γεωγραφία - geografia) is the study of the Earth and its lands features inhabitants and phenomena Economics is the social science that studies the production distribution, and consumption of goods and services. Sociology (from Latin: socius "companion" and the suffix -ology "the study of" from Greek λόγος lógos "knowledge" Epidemiology is the study of factors affecting the Health and Illness of populations and serves as the foundation and Logic of interventions made in the Demographic research is conducted in universities, in research institutes as well as in statistical departments and in several international agencies. Population institutions are part of the Cicred (International Committee for Coordination of Demographic Research) network while most individual scientists engaged in demographic research are members of the International Union for the Scientific Study of Population – IUSSP or, in the United States, in the Population Association of America. The Committee for International Cooperation in National Research in Demography, commonly known as CICRED, is a Non-governmental organization accredited with the

Notes

See also

• Demographics of present-day nations and states
• Biodemography
• Biodemography of human longevity
• Demographic analysis
• Linguistic demography
• Nurgaliev's law
• Religious demography
• Gompertz-Makeham law of mortality
• Important publications in demography
• Medieval demography
• Population
• Population geography
• Population statistics
• Reproductive health
• Sociology
• Social surveys: General Social Survey, ALLBUS, GSOEP, PSID, European Social Survey, World Values Survey, National Longitudinal Survey

Further reading

• Glad, John. This is a list of Demographics by country articles including both De jure and De facto independent States inhabited dependent Biodemography is the science dealing with the integration of biology and Demography. Biodemography is a multidisciplinary approach integrating biological knowledge (studies on human biology and animal models with demographic research on human longevity and survival Demographic analysis includes the sets of methods that allow us to measure the dimensions and dynamics of populations Estimating the number of speakers of a given language is not straightforward and various estimates may diverge considerably In Population dynamics, Nurgaliev's equation says {dn \over dt} = an^2 - bn where 'n' is the size of a population a The world's principal Religions and spiritual traditions may be classified into a small number of major groups or world religions'. The Gompertz-Makeham law states that death rate is a sum of age-independent component (Makeham term and age-dependent component (Gompertz function which increases exponentially with Foundations The Protestant Ethic and the Spirit of Medieval Demography is the study of human Demography in Europe during the Middle Ages. In Biology a population is the collection of inter-breeding organisms of a particular Species; in Sociology Population geography is a division of Human geography. It is the study of the ways in which spatial variations in the distribution composition migration and growth of Population statistics is the use of statistics to analyze characteristics or changes to a population Within the framework of WHO 's definition of Health as a state of complete physical mental and social well-being and not merely the absence of disease or infirmity reproductive Sociology (from Latin: socius "companion" and the suffix -ology "the study of" from Greek λόγος lógos "knowledge" The General Social Survey ( GSS) is a survey used to collect Data on Demographic characteristics and attitudes of residents of the United The German General Social Survey ( GGSS/ALLBUS - Die Allgemeine Bevölkerungsumfrage der Sozialwissenschaften is a national Data generation program in Germany The German Socio-Economic Panel (SOEP is a longitudinal panel dataset of the population in Germany. The World Values Survey is an ongoing academic project by Social scientists to assess the state of sociocultural moral religious and political values of different Cultures The National Longitudinal Surveys (NLS are a set of surveys conducted by the US Department of Labor 's Bureau of Labor Statistics, designed to gather information 2008. Future Human Evolution: Eugenics in the Twenty-First Century. Hermitage Publishers, ISBN 1-55779-154-6 [1]
• Preston, Samuel, Patrick Heuveline, and Michel Guillot. 2000. Demography: Measuring and Modeling Population Processes. Blackwell Publishing.
• Paul R. Ehrlich (1968), The Population Bomb Controversial Neo-Malthusianist pamphlet
• Leonid A. Paul Ralph Ehrlich (born May 29 1932 in Philadelphia Pennsylvania) is a renowned Entomologist specializing in Lepidoptera (butterflies The Population Bomb (1968 is a book written by Paul R Ehrlich. Gavrilov & Natalia S. Gavrilova (1991), The Biology of Life Span: A Quantitative Approach. New York: Harwood Academic Publisher, ISBN 3-7186-4983-7
• Phillip Longman (2004), The Empty Cradle: how falling birth rates threaten global prosperity and what to do about it
• Joe McFalls (2007), Population: A Lively Introduction, Population Reference Bureau [2]
• Ben J. Wattenberg (2004), How the New Demography of Depopulation Will Shape Our Future. Phillip Longman (born April 21, 1956, Stuttgart, Baden-Württemberg, Germany) is a renowned demographer. Benjamin J Wattenberg (b August 26, 1933, The Bronx, New York) is an American Neo-conservative commentator and writer Chicago: R. Dee, ISBN 1-56663-606-X
• Andrey Korotayev, Artemy Malkov, & Daria Khaltourina (2006). Andrey Korotayev (born in 1961 is an anthropologist, economic Historian, and sociologist. Introduction to Social Macrodynamics: Compact Macromodels of the World System Growth. Moscow: URSS, ISBN 5-484-00414-4 [3]

External links

• Demographic mapping and reporting for the UK
• Demography at the University of Southampton
• PAA The Population Association of America is a society of professionals working in the population field. PAA members include demographers, sociologists, economists and public health professionals.
• Demography Demography is the official journal of the Population Association of America.
• International Institute for Applied Systems Analysis (IIASA) IIASA is a non-governmental research institution studying sustainability and the human dimensions of global change for the scientific community, policy makers and the public.
• Centre for Population Studies, London School of Hygiene & Tropical Medicine, the UK's largest research centre focusing on demography and reproductive health.
• Rivista Italiana di Economia Demografia e Statistica RIEDS, Italian Review of Economics Demography and Statistics, Sieds(in Italian, some articles are in English). Italian society of economics demography and statistics ( SIEDS - Società italiana di economia demografia e statistica) is a cultural and scientific institution aiming
• Committee for International Cooperation in National Research in Demographyaims at developing cooperation amongst national population research centres, and encouraging new research
• Max Planck Institute for Demographic Research The MPIDR began its activities in October 1996, but it has already become one of the largest non-governmental research bodies in demography in the world.
• Population Studies a journal of demography.
• Online Journal Demographic Research A free, open access, expedited, peer-reviewed journal of the population sciences published regularly on the web.
• Historicalstatistics.org Links to historical demographic and economic statistics
• The Population Reference Bureau has two introduction to demography texts on line. "Population Handbook" and "Population: A Lively Introduction".
• Population Studies Center at the University of Michigan one of the oldest and most active demography research centers in the United States.
• Hopkins Population Center Hopkins Population Center was established in 1971 with a mandate to stimulate and facilitate interdisciplinary population research. It is the only NICHD funded center in a school of public health.
• Population Studies Center at the University of Pennsylvania since 1962 turning life into statistics.
• Department of Demography, University of California, Berkeley
• Département de démographie, Université de Montréal
• Department of Demography,Cedeplar, Universidade Federal de Minas Gerais, Brazil
• Institute National d'Etudes Démographiques French National Institute
• Population and Health graduate program Population and Health Graduate Program in the Dept of Population and Family Health Sciences at the Johns Hopkins Bloomberg School of Public Health
• Center for Demography and Ecology at the University of Wisconsin,Madison one of the leading centers of demographic research in the world.
• CensusScope U. S. Social Demography site containing data, charts, and color coded maps for country, state, county, and metropolitan geographies.
• PopulationData.net Information and maps about populations around the world. French, with Babelfish translation.
• Phillip Longman, New Statesman, 31 May 2004, "Everywhere, even in Africa, the world is running out of children"
• Ed Stephan's Timeline of Demography Highlights in the history of demography from 3800 BC to 2000 AD. The New Statesman is a British Left-wing political Magazine published weekly in London. Events 1279 BC - Rameses II (The Great (19th dynasty becomes pharaoh of Ancient Egypt. "MMIV" redirects here For the Modest Mouse album see " Baron von Bullshit Rides Again "
• United Nations Population Division Homepage(e. g. Population Estimates and Projections Data Online)
• UN 2004 population projections
• NationMasterNationMaster is a vast compilation of data from such sources as the CIA World Factbook, UN, and OECD.
• Java Simulation of Population Dynamics.