Population statistics
Encyclopedia
Population statistics is the use of statistics
to analyze characteristics or changes to a population. It is related to social demography and demography
.
Population statistics can analyze anything from global demographic changes to local small scale changes. For example, an analysis of global change shows that population growth has slowed, infant mortality rates have declined and there have been small increases in the aged.
. However, because these are usually huge logistical exercises, countries normally conduct censuses only once every five to 10 years. Even when a census is conducted it may miss counting everyone (known as undercount). Also, some people counted in the census may be recorded in a different place than where they usually live, because they are travelling, for example (this may result in overcounting). Consequently, raw census numbers are often adjusted to produce census estimates that identify such statistics as resident population, residents, tourists and other visitors, nationals and aliens(non-nationals). For privacy reasons, particularly when there are small counts, some census results may be rounded, often to the nearest ten, hundred, thousand and sometimes randomly up, down or to another small number such as within 3 of the actual count.
Between censuses, administrative data collected by various agencies about population events such as births, deaths, and cross-border migration may be use to produce intercensal estimate
s.
Some estimates, such as the Usually resident population estimate who usually lives in a locality as at the census date, even though the census did not count them within that locality. Census questions usually include a questions about where a person usually lives, whether they are a resident or visitor, or also live somewhere else, to allow these estimates to be made.
Other estimates are concerned with estimating population on a particular date that is different to the census date, for example the middle or end of a calendar or financial year. These estimates often use birth and death records and migration data to adjust census counts for the changes that have happened since the census.
Population projections are produced in advance of the date they are for. They use time series analysis of existing census data and other sources of population information to forecast the size of future populations. Because there are unknown factors that may affect future population changes, population projections often incorporate high and low as well as expected values for future populations. Population projections are often recomputed after a census has been conducted.
about the census is probably of as much value as the statistics themselves as it allows researchers to determine not only what was being counted but how and why it was done.
Statistics
Statistics is the study of the collection, organization, analysis, and interpretation of data. It deals with all aspects of this, including the planning of data collection in terms of the design of surveys and experiments....
to analyze characteristics or changes to a population. It is related to social demography and demography
Demography
Demography is the statistical study of human population. It can be a very general science that can be applied to any kind of dynamic human population, that is, one that changes over time or space...
.
Population statistics can analyze anything from global demographic changes to local small scale changes. For example, an analysis of global change shows that population growth has slowed, infant mortality rates have declined and there have been small increases in the aged.
Collection
National population statistics are usually collected by conducting a censusCensus
A census is the procedure of systematically acquiring and recording information about the members of a given population. It is a regularly occurring and official count of a particular population. The term is used mostly in connection with national population and housing censuses; other common...
. However, because these are usually huge logistical exercises, countries normally conduct censuses only once every five to 10 years. Even when a census is conducted it may miss counting everyone (known as undercount). Also, some people counted in the census may be recorded in a different place than where they usually live, because they are travelling, for example (this may result in overcounting). Consequently, raw census numbers are often adjusted to produce census estimates that identify such statistics as resident population, residents, tourists and other visitors, nationals and aliens(non-nationals). For privacy reasons, particularly when there are small counts, some census results may be rounded, often to the nearest ten, hundred, thousand and sometimes randomly up, down or to another small number such as within 3 of the actual count.
Between censuses, administrative data collected by various agencies about population events such as births, deaths, and cross-border migration may be use to produce intercensal estimate
Intercensal estimate
Intercensal estimate in the field of demographics is an estimate of population between official census dates. Some nations produce regular intercensal estimates while others do not...
s.
Population estimates and projections
Population estimates are usually derived from census and other administrative data. Population estimates are normally produced after the date the estimate is for.Some estimates, such as the Usually resident population estimate who usually lives in a locality as at the census date, even though the census did not count them within that locality. Census questions usually include a questions about where a person usually lives, whether they are a resident or visitor, or also live somewhere else, to allow these estimates to be made.
Other estimates are concerned with estimating population on a particular date that is different to the census date, for example the middle or end of a calendar or financial year. These estimates often use birth and death records and migration data to adjust census counts for the changes that have happened since the census.
Population projections are produced in advance of the date they are for. They use time series analysis of existing census data and other sources of population information to forecast the size of future populations. Because there are unknown factors that may affect future population changes, population projections often incorporate high and low as well as expected values for future populations. Population projections are often recomputed after a census has been conducted.
History
While many censuses were conducted in antiquity, there are few population statistics that survive. One example though can be found in the Bible, in chapter 1 of the Book of Numbers. Not only are the statistics given, but the method used to compile those statistics is also described. In modern day terms, this metadataMetadata
The term metadata is an ambiguous term which is used for two fundamentally different concepts . Although the expression "data about data" is often used, it does not apply to both in the same way. Structural metadata, the design and specification of data structures, cannot be about data, because at...
about the census is probably of as much value as the statistics themselves as it allows researchers to determine not only what was being counted but how and why it was done.
Metadata
Modern population statistics are normally accompanied by metadata that explains how the statistics have been compiled and adjusted to compensate for any collection issues.Statistical sources
Most countries have a census bureau or government agency responsible for conducting censuses. Many of these agencies publish their country's census results and other population statistics on their agency's website.See also
- CensusCensusA census is the procedure of systematically acquiring and recording information about the members of a given population. It is a regularly occurring and official count of a particular population. The term is used mostly in connection with national population and housing censuses; other common...
- Census Bureau, Census tractCensus tractA census tract, census area, or census district is a geographic region defined for the purpose of taking a census. Usually these coincide with the limits of cities, towns or other administrative areas and several tracts commonly exist within a county...
, Census block groupCensus block groupA census block group is a geographical unit used by the United States Census Bureau which is between the census tract and the census block. It is the smallest geographical unit for which the bureau publishes sample data, i.e data which is only collected from a fraction of all households.Census...
, Census blockCensus blockA census block is the smallest geographic unit used by the United States Census Bureau for tabulation of 100-percent data . Several blocks make up block groups, which again make up census tracts. There are on average about 39 blocks per block group, but there are variations...
. - Intercensal estimateIntercensal estimateIntercensal estimate in the field of demographics is an estimate of population between official census dates. Some nations produce regular intercensal estimates while others do not...
- Population projectionPopulation projectionPopulation projection, in the field of demography, is an estimate of a future population. In contrast with intercensal estimates and censuses, which usually involve some sort of field data gathering, projections usually involve mathematical models based only on pre-existing data. A projection may...