This section is about demographic and social terms. Demography pertains to statistics about population. Therefore, the principal work on this subject is done by the Bureau of the Census, the agency that conducts a decennial census of the population, takes monthly current population surveys, and prepares periodic population estimates.

Everyone knows the Bureau of the Census, that's the agency that visits us each ten years. The Constitution provides for a Decennial Census, that is, a census of the

population every ten years, primarily to establish a basis for apportionment of Members of the House of Representatives among the States. For over a century after the first census in 1790, the census organization was a temporary one. In 1902, the Bureau of the Census was established as a permanent Federal agency, responsible for enumerating the population and also for compiling statistics on other subjects and at other times.

Demographic and Social Terms presents, in alphabetical order, definitions of many

of the technical expressions that are often used in the Bureau of the Census publications. These are based on the 1970 Census of Population, the Current Population Survey, and the program of population estimates and projections. The Current Population Survey (CPS) is a nationwide sample survey conducted monthly by the Bureau of the Census. The concepts and definitions used in the Current Population Survey and in the 1970 Census are generally the

same.

Allocations

Central City and Urban Fringe

Children Ever Born

Class of Worker

The term allocation means that a characteristic (e.g., age, race, relationship) was assigned to a person in the absence of an acceptable (machine-readable) entry on the census or survey questionnaire, or that the entry was changed during the computer editing to make it consistent with other entries on the questionnaire. Allocation may be required as a result of such errors as failure to obtain the required information from respondents, obtaining incorrect or inconsistent information, and recording information in the wrong place or incorrectly. Errors can also occur during the field review of the enumerator's work, the clerical handling of the questionnaires, and the various stages of the electronic processing of the material. The general procedure for changing unacceptable entries is to assign an entry for a person that is consistent with entries for other persons with similar characteristics. Thus, a person who was reported as a 20-year-old son of the household head, but for whom marital status was not reported, was assigned the same marital status as that of the last son processed in the same age group. The objective of the editing of unacceptable entries is to produce a set of statistics that describes the population as accurately as possible.

The urbanized area population is sometimes divided into the population in the central city (or cities) and the population in the remainder of the area or the urban fringe. The central city population normally consists of the population of the cities named in the title of the urbanized area. For a city to be listed in the title, it must be the largest city in the urbanized area or it must have (a) 250,000 inhabitants or more, or (b) at least one-third the population of the largest city and a population of 25,000 or more (except in the case of the small twin cities). There is generally one urbanized area in each standard metropolitan statistical area. Sometimes, however, there are two because there exists another qualifying city with 50,000 inhabitants or more whose surrounding urban fringe is separate from the urban fringe of the larger central city or cities.

The number of children ever born is intended to represent the number of babies a woman has ever had, not counting stillbirths. Children born to the woman before her present marriage, children no longer living, and children away from home, as well as children born to the women who are still living at home, are included. Stepchildren or adopted children are excluded. In the CPS, single (never-married) women are presumed to be childless, but in the 1970 Census, each woman, without restriction, was asked to report on the number of children she had ever borne. Many of the unwed mothers living with an illegitimate child may have reported themselves as having been married in the CPS or the census.

Class of worker refers to the classification of the worker as private wage and salary worker, government worker, selfemployed worker, or unpaid family worker. Private wage and salary workers work for a private employer for wages, salary, commission, tips, pay-in-kind, or at piece rates. Government workers work for a governmental unit, regardless of the activity of the particular agency or the level of government. Selfemployed workers have their own unincorporated business,

Class of Worker (Cont'd)

Employed and Unemployed Persons

Ethnic Origin

Family

profession, or trade, or operate a farm for profit or fees. Unpaid family workers work without pay on a farm or in a business operated by a person to whom they are related by blood or marriage. Placement of a worker in a particular class-ofworker category is in most cases independent of the occupation or industry in which he worked. The data on class of worker are generally for persons who worked in the reference week and pertain to the job held during that week.

Employed persons comprise (1) all civilians who, during a specified week, did any work at all as paid employees or in their own business or profession, or on their own farm, or who worked 15 hours or more as unpaid workers on a farm or in a business operated by a member of the family, and (2) all those who were not working but who had jobs or businesses from which they were temporarily absent because of illness, bad weather, vacation, or labor-management dispute, or because they were taking time off for personal reasons, whether or not they were paid by their employers for time off, and whether or not they were seeking other jobs. Excluded from the employed group are persons whose only activity consisted of work around the house (such as own home housework, painting or repairing own home, etc.) or volunteer work for religious, charitable, and similar organizations.

Unemployed persons are those civilians who, during a specified week, had no employment but were available for work and (1) had engaged in any specific jobseeking activity within the past 4 weeks, such as registering at a public or private employment office, meeting with prospective employers, checking with friends or relatives, placing or answering advertisements, writing letters of application, or being on a union or professional register; (2) were waiting to be called back to a job from which they had been laid off; or (3) were waiting to report to a new wage or salary job within 30 days.

Ethnic origin refers to a classification of the population into groups distinguished by origin or descent, mother tongue, language usually spoken in the home, country of origin, etc. The data presented on origin are derived from replies to questions that ask for self-identification on the basis of the person's origin or descent. Ethnic origin may also be inferred from information on place of birth, country of origin, language usually spoken in the home, mother tongue, surname, etc. The answers to the questions on ethnic origin produce results somewhat different from results based on inferred ethnic identification using the characteristics mentioned. Some respondents having a diverse ethnic background or having several generations of residence in the United States may have reported the ethnic association they felt most strongly or may have made an arbitrary choice.

A family is defined as a group of two or more persons residing together who are related by blood, marriage, or adoption. All such persons are considered as members of one family even though they may include a "subfamily," that is, a married couple or a parent-child group related to and sharing the living quarters of the family head. A "primary family" includes among its members the head of a household and all household

Family

(Cont'd)

Farm and Nonfarm Population

Fertility Ratio

Group Quarters

members who are related to the head by blood, marriage, or adoption. A "secondary family" includes only persons not related to the household head. Secondary families may include persons such as lodgers or resident employees and their relatives living in a household. A "husband-wife" family is one in which the head is a married man whose wife lives with him. The total number of families in data from the CPS is the sum of primary families and secondary families. Because of the small number of secondary families, only primary families are recognized as families in 1970 Census statistics. Members of secondary families are counted as unrelated individuals in the census.

The farm population refers to rural residents living on farms. The farm population consists of all persons living in rural territory on places of less than 10 acres yielding agricultural products which sold for $250 or more in the previous year, or on places of 10 acres or more yielding agricultural products which sold for $50 or more in the previous year. Rural persons in institutions, motels, and tourist camps, and those living on rented places where no land is used for farming are not classified as farm population.

The fertility ratio (or general fertility ratio) represents the number of children under 5 years of age per 1,000 women 15 to 49 years of age. It is a measure of fertility based entirely on census or survey data. It is superior to the birth rate for making comparisons of the rate at which women are having children because it eliminates the effect of the variation in the proportion of women of childbearing age in the population. The fertility ratio reflects the actual fertility level in the five years preceding the census or survey, and hence is affected by the deaths of the children and mothers between the birth dates of the children and the census or survey date.

All persons not living in households are classified as living in group quarters. Among persons living in group quarters are inmates of institutions. Inmates are persons under care or custody at the time of the census or survey in homes, schools, hospitals or wards for juveniles, the physically handicapped, the mentally handicapped; hospitals for mental, tuberculosis, or chronic disease patients; homes for unwed mothers; nursing, convalescent and rest homes; homes for the aged and dependent; and correctional institutions. Such persons were enumerated as "patient or inmate" of an institution regardless of their length of stay in that place and regardless of the number of people in the particular place.

The population in group quarters includes, in addition to inmates of institutions, the population in certain other types of living quarters, namely those units which are occupied by five or more persons unrelated to the head, or, when no head is designated, which are shared by six or more unrelated persons. Rooming and boarding houses, communes, farm and nonfarm workers' dormitories, and convents or monasteries generally fall into this category. Persons residing in military barracks, on ships, in college dormitories, sorority and fraternity houses, patients in short-term medical and surgical wards of hospitals who have no usual residence elsewhere,