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Population Change
Population change is simply the change in the number of people in a specified area during a specific time period. Demographics (or demography) is the study of population statistics, their variation and its causes. These statistics include birth rates, death rates (and hence life expectancy), migration rates and sex ratios. All of these statistics are investigated by censuses and surveys conducted over a period of time. Some demographic information can also be obtained from historical maps, and aerial photographs. A major purpose of demography is to inform government and business planning of the resources that will be required as a result of population changes. Population trends The change in total population over a period is equal to the number of births, minus the number of deaths, plus or minus the net amount of migration in a population. The number of births can be projected as the number of females at each relevant age multiplied by the assumed fertility rate. The number of d ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Demographics
Demography () is the statistical study of human populations: their size, composition (e.g., ethnic group, age), and how they change through the interplay of fertility (births), mortality (deaths), and migration. Demographic analysis examines and measures the dimensions and dynamics of populations; it can cover whole societies or groups defined by criteria such as education, nationality, religion, and ethnicity. Educational institutions usually treat demography as a field of sociology, though there are a number of independent demography departments. These methods have primarily been developed to study human populations, but are extended to a variety of areas where researchers want to know how populations of social actors can change across time through processes of birth, death, and migration. In the context of human biological populations, demographic analysis uses administrative records to develop an independent estimate of the population. Demographic analysis est ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Birth Rate
Birth rate, also known as natality, is the total number of live childbirth, human births per 1,000 population for a given period divided by the length of the period in years. The number of live births is normally taken from a universal registration system for births; population counts from a census, and estimation through specialized Demographics, demographic techniques such as population pyramids. The birth rate (along with mortality rate, mortality and human migration, migration rates) is used to calculate population growth. The estimated average population may be taken as the mid-year population. When the crude death rate is subtracted from the crude birth rate (CBR), the result is the rate of natural increase (RNI). This is equal to the rate of population change (excluding migration). The total (crude) birth rate (which includes all births)—typically indicated as births per 1,000 population—is distinguished from a set of age-specific rates (the number of births per 1,0 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Death Rates
Mortality rate, or death rate, is a measure of the number of deaths (in general, or due to a specific cause) in a particular population, scaled to the size of that population, per unit of time. Mortality rate is typically expressed in units of deaths per 1,000 individuals per year; thus, a mortality rate of 9.5 (out of 1,000) in a population of 1,000 would mean 9.5 deaths per year in that entire population, or 0.95% out of the total. It is distinct from "morbidity", which is either the prevalence or incidence of a disease, and also from the incidence rate (the number of newly appearing cases of the disease per unit of time). An important specific mortality rate measure is the crude death rate, which looks at mortality from all causes in a given time interval for a given population. , for instance, the CIA estimates that the crude death rate globally will be 7.7 deaths per 1,000 people in a population per year. In a generic form, mortality rates can be seen as calculated using (d ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Human Migration
Human migration is the movement of people from one place to another, with intentions of settling, permanently or temporarily, at a new location (geographic region). The movement often occurs over long distances and from one country to another (external migration), but internal migration (within a single country) is the dominant form of human migration globally.World Migration Report' Migration is often associated with better human capital at both individual and household level, and with better access to migration networks, facilitating a possible second move. It has a high potential to improve human development, and some studies confirm that migration is the most direct route out of poverty. Age is also important for both work and non-work migration. People may migrate as individuals, in family units or in Mass migration, large groups. There are four major forms of migration: invasion, conquest, colonization and emigration/immigration. People moving from their home due to force ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
One-child Policy
The one-child policy ( zh, c=一孩政策, p=yī hái zhèngcè) was a population planning initiative in China implemented between 1979 and 2015 to curb the country's population growth by restricting many families to a single child. The program had wide-ranging social, cultural, economic, and demographic effects, although the contribution of one-child restrictions to the broader program has been the subject of controversy. Its efficacy in reducing birth rates and defensibility from a human rights perspective have been subjects of controversy. China's family planning policies began to be shaped by fears of overpopulation in the 1970s, and officials raised the age of marriage and called for fewer and more broadly spaced births. A near-universal one-child limit was imposed in 1980 and written into the country's constitution in 1982. Numerous exceptions were established over time, and by 1984, only about 35.4% of the population was subject to the original restriction of the pol ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Population Pyramid
A population pyramid (age structure diagram) or "age-sex pyramid" is a graphical illustration of the distribution of a population (typically that of a country or region of the world) by age groups and sex; it typically takes the shape of a pyramid when the population is growing. Males are usually shown on the left and females on the right, and they may be measured in absolute numbers or as a percentage of the total population. The pyramid can be used to visualize the age of a particular population. It is also used in ecology to determine the overall age distribution of a population; an indication of the reproductive capabilities and likelihood of the continuation of a species. Number of people per unit area of land is called population density. Structure A population pyramid often contains continuous stacked-histogram bars, making it a horizontal bar diagram. The population size is shown on the x-axis (horizontal) while the age-groups are represented on the y-axis (vertical). The ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
