Collection
National population statistics are usually collected by conducting a census. 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 used to produce intercensal estimates.
Read more about this topic: Population Statistics
Famous quotes containing the word collection:
“What is all wisdom save a collection of platitudes? Take fifty of our current proverbial sayings—they are so trite, so threadbare, that we can hardly bring our lips to utter them. None the less they embody the concentrated experience of the race and the man who orders his life according to their teaching cannot go far wrong.”
—Norman Douglas (1868–1952)
“We’ll never know the worth of water till the well go dry.”
—18th-century Scottish proverb, collected in James Kelly, Complete Collection of Scottish Proverbs, no. 351 (1721)
“Only the history of free peoples is worth our attention; the history of men under a despotism is merely a collection of anecdotes.”
—Sébastien-Roch Nicolas De Chamfort (1741–1794)