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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, and it is also vital to democracy (voting).


Ancient censuses

Rome conducted censuses to determine taxes. The word census derives from the Latin censor, which was the title of the official in charge of counting Romans and setting tax rates.

The Bible relates stories of several censuses. The Book of Numbers describes a divinely-mandated census that occurred when Moses led the Israelites from Egypt. A later census called by King David of Israel, referred to as the "numbering of the people," incited divine retribution (for being militarily motivated ?). A Roman census is also mentioned in one of the best known passages of the Bible in the Gospel of Luke.

The world's oldest extant census comes from China during the Han Dynasty. Taken in the fall of 2 AD, it is considered by scholars to be quite accurate. At that time there were 57.5 million living in Han China, the world's largest population. The second oldest preserved census is also from the Han, dating back to 140 AD, when only a bit more than 48 million people were recorded. Mass migrations into what is today southern China are believed to be behind this massive demographic decline.

Modern censuses


The Australian census is run by the Australian Bureau of Statistics. It is carried out every five years, the last one being on August 7, 2001.


The Brazilian census is carried out by IBGE, the Brazilian Institute of Geography and Statistics, every 10 years. The last one was in 2000.


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.

See also: Canada 2001 Census


Napoleon Bonaparte began the census in France as a means of determining the number of potential soldiers under his rule. Today, the census in France is carried out by INSEE. Since 2004, a partial census is carried out every year, and the results published as averages over 5 years.


The first large-scale census in the German Empire took place in 1895. Attempts at introducing a census in Germany sparked strong popular resentment in the 1980s since many quite personal questions were asked. Some campaigned for a boycott. In the end the Constitutional Court stopped the census in 1980 and 1983. The last census was in 1987. Germany has since used population samples in combination with statistical methods, in place of a full census.


The census in Italy is carried out by ISTAT every 10 years. The last four were in 1971, 1981, 1991, 2001.

New Zealand

(see main article) The census in New Zealand is carried out by Statistics New Zealand (Te Tari Tatau), every five years. The last was in 2001, the next will be in 2006.


The census in Portugal is carried out by INE every 10 years. The last one occurred in 2001.


In Russia the first All-Russia Population Census was carried out in 1897. All-Union Population Censuses were carried out in the USSR (which included Russia and the other republics) in 1920, 1926, 1939, 1959, 1970, 1979 and 1989). The first (post-Soviet) All-Russia Population Census was carried out in 2002. The census is now the responsibility of the Federal State Statistics Service.

South Africa

The census in South Africa is carried out every 5 years by Statistics South Africa. The only two to date were in 1996 and 2001.

United Kingdom

The UK census as we know it today started in 1801 (championed by John Rickman who managed the first four up to 1831), partly 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 for tax purposes. Dalriada (now Scotland) in the 7th century was the 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').

Rickman's 12 reasons - set out in 1798 and repeated in Parliamentary debates - for conducting a UK census included the following justifications:

  • 'the intimate knowledge of any country must form the rational basis of legislation and diplomacy'
  • 'an industrious population is the basic power and resource of any nation, and therefore its size needs to be known'
  • 'the number of men who were required for conscription to the militia in different areas should reflect the area's population'
  • 'there were defence reasons for wanting to know the number of seamen'
  • 'the need to plan the production of corn and thus to know the number of people who had to be fed'
  • 'a census would indicate the Government's intention to promote the public good' and
  • 'the life insurance industry would be stimulated by the results.'

The census has been conducted every ten years since 1801 and most recently in 2001. The first four censuses (1801-1831) were mainly statistical (that is, they were mainly headcounts and contained virtually no personal information). The 1841 Census was the first to record names of all individuals in a household or institution.

Because of the war, there was no census in 1941. However, following the passage into law (on 5 September 1939) of the National Registration Act a population count was carried out on 29 September 1939, which was, in effect, a census.

The census is undertaken by the government for policy and planning purposes, and the (statistical) information is also sold to interested parties. Public access to the census returns is restricted under the terms of the 100-year rule and the most recent returns made available to researchers are those of the 1901 Census.

The census is usually very accurate, and with a fine of up to 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, Buddhists or Jews), with some areas registering up to 2.6% of people as Jedi.

See also: UK census dates, Population of England, Census Enumerators' Books, Citizen Information Project

External links

United States

The United States Constitution mandates that the census be taken at least once every ten years (U.S. Congress could require a more frequent census by legislation), and that the number of members of the House of Representatives from each state be determined accordingly. In addition, Census Bureau statistics are used for apportioning Federal funding for many social and economic programs. But there is not a federal census legislation (nor for federal voting).

The first U.S. Census was taken in 1790 by the local U.S. Marshals. Census-takers went door-to-door and recorded the number of people in each household, and the name of the head of the household. Slaves were counted, but for apportionment purposes each counted as only three-fifths of a citizen. American Indians being neither taxed nor considered during apportionment, were not counted. The first census counted 3.9 million people, less than half the population of New York City in 2000. The 2000 census counted over 281 million people.

In 1902, a Public Law established the Census Bureau as a permanent Federal agency. Until the 2010 census, there were two forms of questionnaire – long and short. Currently, the plan is to replace the Long form in 2010 with the American Community Survey (ACS), but funding for ACS is not assured, in which case there may be a long form in the 2010 census. Computer algorithms (based on complex sampling rules) determine which form was mailed to a given household (in practice, of those households whose locations are on the Census Master Address List), one in six receiving the long form. This was supplemented by census workers who go door-to-door to talk to people who fail to 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. While some critics claim that census questions are an invasion of privacy, the data collected by every question is either required to enforce some federal law (such as the Voting Rights Act) or is required to administer some federal program. Congress gives approval to every question asked on the Census.

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. The Supreme Court has ruled that only an actual head count can be used to apportion Congressional seats; however, cities and minority representatives have complained that urban residents and minorities are undercounted. In several cases, the Census Bureau will recount an area with disputed figures, provided the local government pays for the time and effort. The State of Utah protested the figures of the 2000 decennial census because it lost a seat in the House of Representatives to North Carolina. Had the Census Bureau been able to count the numbers of Utahns living overseas, including many Mormon missionaries, Utah would have retained the seat.

To minimize the burden on individuals and to provide improved data, the Bureau is preparing several alternative methods for gathering economic, demographic, and social information, including the American Community Survey and record linking of depersonalized administrative records with other administrative records and Census Bureau surveys.

By law (92 Stat. 915, Public Law 95-416, enacted on October 5, 1978), census records are sealed for 72 years; in an era when life expectancy was under 60 years, this attempts to protect individual's privacy by prohibiting the release of such information during their expected lifetimes. Thus, the most recent Census released to the public was the 1930 Census, released in 2002.

Indicies to some of the U.S. Censuses have been produced over the years, making the process of searching old census records much easier. Some indicies of census records have been produced by amateur volunteer genealogists. Due to the sheer volume of information, and the manual methodologies involved, the indexing used to be limited to the head-of-household. These indexes were published in bound volumes and are often available in regional libraries along with microfilm rolls that can be researched.

While valuable, indicies produced from these censuses can be problematic to use. The original census records from this era were completed by hand by census enumerators; this leads to problems in handwriting recognition and variations in spelling of surnames within the original documents.

The 1880--1920 censuses have indexes of last names, produced using the Soundex system; the indexing project was performed by the Works Progress Administration. The Soundex system is tolerant of variations in spelling; names with similar sounds but different spellings have the same encoding. The chief motivation in producing the Soundex name indicies was to assist citizens in finding census records to provide evidence of age, especially for those born before the advent of governmentally-approved birth certificates. (Verification of age was needed to establish eligibility for old-age benefits such as Social Security). Partial Soundex indicies of the 1930 census are available; resources from the Works Progress Administration were diverted towards support of World War II efforts before the project was completed.

With the advent of computers, and more recently, the Internet, expanded indexes including all family members are beginning to appear on genealogy websites. These are accompanied with hypertext links that take the researcher directly to an image of the original census page, without having to travel to a regional library and scroll through endless rolls of microfilm.

Genealogists view censuses as secondary sources of information; primary sources of information such as birth certificates are viewed as more reliable. Still, census information often provides useful information for genealogists and clues on where to proceed to find further primary source documents.


In additional to the decennial federal census, more localized versions are often used. An example of this is Massachusetts, which takes a statewide census every fifth year. Likewise, each community in Massachusetts takes a municipal census each year.


Last updated: 10-25-2005 12:43:17
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