Census taker visits a Romani family living in a caravan, Netherlands 1925

A census is the procedure of systematically acquiring and recording information about the members of a given population. The term is used mostly in connection with national population and housing censuses; other common censuses include agriculture, business, and traffic censuses. The United Nations defines the essential features of population and housing censuses as "individual enumeration, universality within a defined territory, simultaneity and defined periodicity", and recommends that population censuses be taken at least every 10 years. United Nations recommendations also cover census topics to be collected, official definitions, classifications and other useful information to co-ordinate international practice.[1][2]

The word is of Latin origin: during the Roman Republic, the census was a list that kept track of all adult males fit for military service. The modern census is essential to international comparisons of any kind of statistics, and censuses collect data on many attributes of a population, not just how many people there are. Censuses typically began as the only method of collecting national demographic data, and are now part of a larger system of different surveys. Although population estimates remain an important function of a census, including exactly the geographic distribution of the population, statistics can be produced about combinations of attributes e.g. education by age and sex in different regions. Current administrative data systems allow for other approaches to enumeration with the same level of detail but raise concerns about privacy and the possibility of biasing estimates.[3]

A census can be contrasted with sampling in which information is obtained only from a subset of a population; typically main population estimates are updated by such intercensal estimates. Modern census data are commonly used for research, business marketing, and planning, and as a baseline for designing sample surveys by providing a sampling frame such as an address register. Census counts are necessary to adjust samples to be representative of a population by weighting them as is common in opinion polling. Similarly, stratification requires knowledge of the relative sizes of different population strata which can be derived from census enumerations. In some countries, the census provides the official counts used to apportion the number of elected representatives to regions (sometimes controversially – e.g., Utah v. Evans). In many cases, a carefully chosen random sample can provide more accurate information than attempts to get a population census.[4]


A census is often construed as the opposite of a sample as its intent is to count everyone in a population rather than a fraction. However, population censuses rely on a sampling frame to count the population. This is the only way to be sure that everyone has been included as otherwise those not responding would not be followed up on and individuals could be missed. The fundamental premise of a census is that the population is not known and a new estimate is to be made by the analysis of primary data. The use of a sampling frame is counterintuitive as it suggests that the population size is already known. However, a census is also used to collect attribute data on the individuals in the nation. This process of sampling marks the difference between historical census, which was a house to house process or the product of an imperial decree, and the modern statistical project. The sampling frame used by census is almost always an address register. Thus it is not known if there is anyone resident or how many people there are in each household. Depending on the mode of enumeration, a form is sent to the householder, an enumerator calls, or administrative records for the dwelling are accessed. As a preliminary to the dispatch of forms, census workers will check any address problems on the ground. While it may seem straightforward to use the postal service file for this purpose, this can be out of date and some dwellings may contain a number of independent households. A particular problem is what are termed 'communal establishments' which category includes student residences, religious orders, homes for the elderly, people in prisons etc. As these are not easily enumerated by a single householder, they are often treated differently and visited by special teams of census workers to ensure they are classified appropriately.

Other Languages
Afrikaans: Sensus
العربية: إحصاء السكان
Bân-lâm-gú: Phó͘-cha
беларуская (тарашкевіца)‎: Перапіс насельніцтва
भोजपुरी: जनगणना
brezhoneg: Niveradeg
Чӑвашла: Çырсатуху
čeština: Sčítání lidu
Cymraeg: Cyfrifiad
Deutsch: Volkszählung
Ελληνικά: Απογραφή
Esperanto: Popolnombrado
فارسی: سرشماری
Gaeilge: Daonáireamh
galego: Censo
한국어: 인구 조사
հայերեն: Մարդահամար
हिन्दी: जनगणना
Ido: Censo
Bahasa Indonesia: Sensus
interlingua: Censo
íslenska: Manntal
italiano: Censimento
Basa Jawa: Cacah sirah
ქართული: ცენზი
қазақша: Халық санағы
Kiswahili: Sensa
Кыргызча: Эл каттоо
Latina: Census
Limburgs: Voukstèlling
македонски: Попис
മലയാളം: കാനേഷുമാരി
मराठी: जनगणना
Bahasa Melayu: Banci
မြန်မာဘာသာ: သန်းခေါင်စာရင်း
Nederlands: Volkstelling
नेपाली: जनगणना
日本語: 国勢調査
нохчийн: Нахбагарбар
norsk nynorsk: Folketeljing
پنجابی: ماݨس گِنتری
Piemontèis: Censiment
Plattdüütsch: Zensus
português: Censo demográfico
română: Recensământ
Runa Simi: Runa yupay
Scots: Census
සිංහල: ජන සංගණන
Simple English: Census
slovenščina: Popis prebivalstva
srpskohrvatski / српскохрватски: Popis stanovništva
Basa Sunda: Sénsus
svenska: Folkräkning
Tagalog: Senso
татарча/tatarça: Җанисәп
తెలుగు: జనాభా గణన
Türkçe: Nüfus sayımı
українська: Перепис населення
Tiếng Việt: Điều tra dân số
Winaray: Senso
ייִדיש: צענזוס
粵語: 人口普查
中文: 人口普查