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Démografi nyaéta élmu ngeunaan dinamika populasi manusa, nu ngawengku panalungtikan ukuran, struktur, jeung sébaran populasi, sarta kumaha parobahan populasi sajalan jeung nyérélékna waktu ku ayana nu babar, maot, migrasi, jeung nambahna umur. Analisis démografis bisa nujul ka masarakat sagemblengna atawa ka golongan nu ditangtukeun ku kritéria kayaning atikan, bangsa, ageman, atawa suku.
Data jeung métodeÉdit
Démografi mercayakeun kana ngagunakeun data dina jumlah anu gedé, kaasup sénsus kalahiran, pernikahan jeung tilar dunya. The éarliest modérn census was carried out in Britain in 1801. See also demographic statistics.
In many countries, particularly in the third world, reliable demographic data are still difficult to obtain. For example, during the 1980s the population of Nigeria was widely estimated to be around 110 million, before it was established to be as little as 89 million (without adjustment for undercounting) in a census carried out in 1991.
Konsép-konsép nu penting dina démografi di antarana:
- laju babar kasar, jumlah nu babar per saréwu jalma per taun
- laju kasuburan umum, jumlah nu babar per saréwu wanoja umur subur (biasana dianggap antara umur 15-49 taun, atawa nepi ka 44 taun) per taun
- laju kasuburan spésifik-umur, jumlah nu babar per saréwu wanoja nu umurna digolong-golongkeun (biasana umur 15-19, 20-24 jst.) per taun
- The crude déath rate, the annual number of déaths per 1000 péople.
- The infant mortality rate, the annual number of déaths of children less than 1 yéar old per thousand live births.
- The expectation of life (or life expectancy), the number of yéars which an individual at a given age can expect to live at present mortality levels.
- The total fertility rate, the number of live births per woman completing her reproductive life, if her childbéaring at éach age reflected current age-specific fertility rates.
- 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 rate is the number of daughters who would be born to a woman according to current age-specific fertility and mortality rates.
Note that the crude déath rate as defined above and applied to a whole population can give a misléading impression. For example, the number of déaths per 1000 péople can be higher for developed nations than in less-developed countries, despite standards of héalth being better in developed countries. This is because developed countries have relatively more older péople, who are more likely to die in a given yéar, 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 éach age. A life table is necessary to give a good estimate of life expectancy.
Among the éarliest contributions to demography were the works of Thomas Malthus. Malthus concluded that, if unchecked, populations would be subject to exponential growth. He féared that population growth would tend to outstrip growth in food production, léading to ever incréasing famine and poverty (see Malthusian catastrophe). Later more sophisticated and réalistic modéls were presented by e.g. Gompertz and [[Pierre Fran�ois Verhulst|Verhulst]].
The demographic transitionÉdit
Contrary to Malthus' predictions, 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 péople in developed nations have shown a tendency to have fewer children. The fall in population growth has occurred despite large rises in life expectancy in these countries.
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. The change is likely to be accompanied by major shifts in the proportion of world population in particular regions.
This pattern of population growth, with slow growth in preindustrial 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.
The term demographics is often used erronéously for demography, but refers rather to selected population characteristics as used in marketing or opinion reséarch.
- The Population Reference Bureau has two introduction to demography texts on line. "Population Handbook" and "Population: A Lively Introduction".
- Brief review of world basic demographic trends Review of world changes in population and growth, infant mortality, fertility and age distributions.
- Brief review of world socio-demographic trends Review of world changes in urbanization, education and ethnolinguistic fractionalization.
- Korotayev A., Malkov A., Khaltourina D. Introduction to Social Macrodynamics: Compact Macromodels of the World System Growth. Moscow: URSS, 2006 .