Census, Population

the process of collecting demographic, economic, and social data characterizing each inhabitant of a country or territory at a definite time or period. In addition, the concept of the census sometimes also refers to the summarizing, processing, and publishing of these data. Censuses are conducted to obtain information on the size, composition, and location of the population. In the socialist countries this information serves as the foundation for state administration and for planning the development of the national economy and culture. State censuses are of “enormous state importance” (V. I. Lenin, Poln. sobr. soch., 5th ed., vol. 51, p. 352).

Population censuses are usually taken by enumerators who visit residential buildings and collect information on each inhabitant by name. Sometimes censuses are taken by mail (the USA, 1970) or at registration points (the People’s Republic of China, 1953). The range of information collected is determined by the program of the census; in general, the same questions are asked of the entire population. Most of the questions are related to demography (sex, age, and family status), economics (employment; sector or type of economic activity; and in the capitalist countries, occupation and sometimes unemployment), education (literacy, school attendance), and ethnic background (nationality, language, and sometimes religious belief). The census also gathers information on citizenship, place of birth, change of residence, physical and mental deficiencies, and military service in time of war. Information indicating affiliation with a particular social group is important. In the socialist countries, class affiliation is determined directly; in the capitalist countries it depends on status at work (for example, employer or wage laborer). Some groups are asked additional questions. For example, married persons are asked the date of marriage, and mothers the number of children in the family. Sometimes a series of questions is asked of a sample of the population. In the USSR in 1970 every fourth household was asked about its place of residence two years before the census.

In taking the census, the principle of self-definition is applied —that is, information is obtained not from documents but by talking with residents. Often, the census seeks information about families or households by asking how the interviewee is related to the head of the family. In some countries information concerning the place of residence is collected, or the population census is taken parallel to the residence census.

The census is taken quickly, in a few days or weeks, at the time of year when people are least mobile (in the USSR, during the winter). However, all information reflects conditions as of the “critical moment,” or census moment (usually midnight before the first day of the census). Persons who die before the critical moment and those born after it are not counted. Responses are entered on standard census sheets or forms by specially trained enumerators (registrars) if the interview method is used, or by the people themselves (the self-census, or self-enumeration). Measures are taken to avoid missing anyone or counting anyone twice. In many countries, evasion of the census and disclosure of private information by census personnel are punishable offenses. The population census is a complex operation demanding comprehensive scientific substantiation, lengthy preparation, and strict organization.

Processing census data is an important operation. After careful examination, the entries on the census sheets are coded, by means of special programming languages, or “dictionaries,” according to characteristics such as employment or nationality. The census entries may also be read by special devices that feed them into calculating machines. The number of inhabitants in particular territories and in the country as a whole is determined (usually by electronic computer), as is the distribution of inhabitants by the characteristics under consideration (age, sex, and employment, for example). The combinations of these characteristics and the corresponding system of groupings in a territorial breakdown are known as the program for processing census data. The program, which is usually detailed, determines the informational value of the census data. The most important data are obtained in advance, sometimes by sampling. Full processing of census data takes several years.

In 18th- and 19th-century Russia the population was counted during the poll-tax revisions. Although the population of certain cities and provinces was recorded in the late 19th century, only one general census was conducted (1897). In the USSR censuses were conducted in 1920, 1923 (urban population only), 1926, 1937 (flawed data), 1939, 1959, and 1970.

In other countries, censuses have been taken regularly since the late 18th and early 19th centuries (in the USA since 1790, in Sweden since 1800, in Great Britain since 1801, in Norway since 1815, and in France since 1831). However, modern population censuses date from the second half of the 19th century. Almost all countries have conducted at least one census. The developed countries conduct censuses every ten years (generally in years ending with a zero or one); some countries conduct them every five years (Japan, Denmark, and Turkey). Censuses are important in the developing countries, where counting the population has not been organized, and taking a census presents great difficulties. The distinguishing features of the modern population census are a detailed program, particularly with respect to questions about education, economic status, and reproduction; extensive use of sampling at all stages of collecting information; and heavy use of computers to process census data.