A census is the process of obtaining information about every member of a population (not necessarily a human population). It can be contrasted with sampling in which information is only obtained from a subset of a population. As such it is a method used for accumulating statistical data.

Table of contents
1 Ancient censuses
2 Canadian Census
3 US Census
4 UK Census
5 French Census
6 Italian Census

Ancient censuses

Rome conducted censuses to determine taxes. The word census derives from the Roman censor, the official in charge of counting Romans and setting tax rates. In the Bible, The Book of Numbers describes a census that occured when Moses led God's people from Egypt. King David also commanded a numbering of the people, and a Roman census is also mentioned in the New Testament of the Bible.

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Canadian Census

The Canadian census is run by Statistics Canada. The first census conducted in Canada was conducted in 1666, by French intendant Jean Talon, when he took a census to ascertain the number of people living in New France. In 1871, Canada's first formal census was conducted, which counted the population of Nova Scotia, Ontario, New Brunswick, and Quebec. In 1918, the Dominion Bureau of Statistics was formed. In 1971, Statistics Canada was formed to replace the Dominion Bureau of Statistics, and consequently, took over its census job.

Censuses in Canada are conducted in five year intervals. The latest census was conducted in 2001 and the next planned census is 2006. Censuses taken in mid-decade (e.g. 1976, 1986, 1996, etc.) are referred to as quinquennial censuses. Others are referred to as decennial censuses. The first quinquennial census was conducted in 1956.

US Census

The US census is—as mandated in the Constitution—taken every ten years, and the results are used for apportioning seats in Congress. The first census was taken in 1790. Today, there are two forms of questionnaire—long and short. A computer determines which form is mailed to a given household (in practice, of those households whose locations are on the federal lists), with one in seven receiving the long form. This is supplemented by census workers who go door-to-door to talk to people who don't return the forms. In addition to a simple count of residents, the Census Bureau collects a variety of statistics, on topics ranging from ethnicity to the presence of indoor plumbing. Despite a massive effort, the Census Bureau has never been able to count every individual, leading to controversy about whether to use statistical methods to supplement the numbers for some purposes, as well as arguments over how to improve the actual head count.

UK Census

The UK census as we know it today started in 1801, as part of a drive to ascertain the number of men able to fight in the Napoleonic wars. England took its first Census when the Domesday Book was compiled in 1086. Dalriada (now Scotland) in the 7th century was first territory in what is now the UK to conduct a census, with what was called the "Tradition of the Men of Alba" (Senchus fer n'Alba').

The census has been conducted every ten years since 1801 (except in 1941), the last one having been completed in 2001. The census is undertaken by the government, and the information is sold to interested parties, as well as being used for policy and planning purposes.

The census is usually very accurate, and with a fine of £1,000 for those who do not complete it, filled in by a high percentage of the population. An exception may have been the census conducted during the years of the poll tax (1991), when some people avoided it in case it was used for enforcing the tax.

The 2001 census was the first year in which the government asked about religion. Perhaps encouraged by a chain letter that started in New Zealand, 390,000 people entered their religion as Jedi Knight (more than either Sikhs, Bushists or Jews), with some areas registering up to 2.6% of people as Jedi.

See also Population of England.

French Census

The census in France is carried out by INSEE.

Italian Census

The census in Italy is carried by ISTAT