This part of the Census Users Dictionary defines the subject concepts recognized in 1960 and/or 1970 population census tabulations. Concepts and their categories and subcategories are included which appear in tabulations the Census Bureau makes available to users through printed publications, computer tapes, and microfilm or microfiche. Concepts are organized under broad headings such as Education, Financial Wellbeing, etc. Concept definitions indicate or are affected by:
Census questions from which the concept is derived . All concepts (tabulation categories) in this section are derived from responses to one or more census questions. In most cases the concepts are directly comparable to specific response categories. This is true for sex, type of school in which enrolled, year moved into present house, vocational training, etc. In other cases, concepts are derived by combining answers to two or more questions to obtain recodes, for instance, in the determination of labor force status and employment status. Where respondents write in answers, Census Bureau personnel determine a code for each handwritten entry according to specified rules. Occupation, industry, income, and mother tongue are among the concepts derived by coding.

Concept categories carried on basic records, but not on summary tapes . For reasons of cost, report size, usefulness, and reliability, fewer concept categories may be tabulated in a particular matrix than are included on the basic records. For instance, the basic records carry some 70 language codes for the concept mother tongue, but only 20 appear on any summary tape or in any printed report. Similarly, one hundred dollar intervals are used in coding income up to a certain maximum on basic records, but income tabulations employ broader income intervals.

Users may request special tabulations on a contract basis which recognize the full range of concept categories carried on the basic records. However, no information will be furnished which violates the confidentiality of the individual.

The universe to which the concept applies . Not all concepts are tabulated (or carried on basic records) for the entire population. Marital status, for instance, is tabulated for persons 14 years of age and over only, country of origin for the foreign stock only, occupation and industry for the experienced civilian labor force and labor reserve only. Quite a few tabulations are made for persons in households only, excluding groups quarters.

The census(es) to which the concept applies (year) . Most concepts apply both to the 1960 and 1970 population censuses. A few are new in 1970; others have additional or different categories or different universes in 1970.

Whether related questions are complete-count or sample . A very few questions are asked of the entire population--only those basic facts about people such as sex and age which are needed to make an accurate count of persons in each area. These are called complete-count or 100-percent items.

All other items about people are obtained from samples. Sampling permits the collection of data about an area which reflect the characteristics of all persons in the area even though only a small number of individuals were actually questioned. This process also allows the data to be obtained at a much lower cost. Sample cases are weighted to reflect the sampling percentages. In a tabulation based on the 20-percent sample, for example, all cases have weights which average 5; that is, all figures are multiplied by 5 so the final figures will be estimates for all the people in an area rather than just 20 percent of them. Control totals for the multiplication are obtained from the 100-percent items.

In 1960, there was a 25-percent sample; in 1970 there will be a 15-percent sample and a 5-percent sample (in order to reduce the length of the questionnaire for any one individual). Certain questions common to both samples will result in a 20-percent sample. Whether a question is asked of everyone or of a sample of people depends in part on the size of the area for which statistics are to be tabulated and published. Basic population data, including that required for apportionment purposes, is collected on a 100-percent basis and published for city blocks. Data which is considered important for areas as small as census tracts and minor civil divisions is to be collected on a 15- or 20- percent sample basis. The 5-percent sample includes items needed for larger cities, counties, standard metropolitan statistical areas, and States.

The sample percentages for population items included in the 1970 census schedules in comparison with items in the 1960 census are shown below.

Instructions for respondents in mail-census areas .The meaning of concepts and categories derived from replies on mailed-back questionnaires (except where Census editing procedures change the replies) depends on respondents interpretation of the questions, which may or may not be as the Census intended. Some interpretive instructions were included with the questionnaire; these are reflected in the concept definitions included in this dictionary.

In the less densely populated areas of the country, enumeration procedures were the same as the single-stage procedure employed in 1960. In addition, special procedures were used to enumerate persons living in certain types of group quarters, such as college dormitories.

Table 1: 1970 Census Items Compared With 1960 Content
Population Items	Complete-count or sample percentage
	1960	1970
Relationship to head of household	100	100
Color or race	100	100
Age (month and year of birth)	100	100
Sex	100	100
Marital Status	100	100
State or country of birth	25	20
Years of school completed	25	20
Number of children ever born	25	20
Activity 5 years ago	-	20
Employment Status	25	20
Hours worked last week	25	20
Weeks worked last year	25	20
Last year in which worked	25	20
Occupation, industry, and class of worker	25	20
Income last year:
Wage and salary income	25	20
Self-employment income	25	120
Other income	25	220
Country of birth of parents	25	15
Mother tongue	25	15
Year moved into this house	25	15
Place of residence 5 years ago	25	315
School or college enrollment (public or private )	25	15
Veteran status	25	15
Place of work	25	415
Means of transportation to work	25	15
Mexican or Spanish origin or descent	-	5
Citizenship	-	5
Year of immigration	-	5
Marital history	25	55
Vocational training completed	-	5
Presence and duration of disability	-	5
Occupation-industry 5 years ago	-	5

Footnotes:

¹Single item in 1960; two-way separation in 1970 by farm and nonfarm income.
²Single item in 1960: three-way separation in 1970 by social security public assistance, and all other receipts.
³This item is also in the 5-percent sample but limited to state of residence 5 years ago.
⁴ Street address included for 1970.
⁵ In 1960, whether married more than once and date of first marriage; in 1970 also includes whether first marriage ended by death of spouse.

Editing and allocation procedures. Extensive efforts are made to ensure that data collected in the decennial population censuses are complete and accurate. Checking for completeness and consistency of replies began at the local district offices which received the mailed-back questionnaires. The questionnaires were then sent to a central processing center, microfilmed, and fed into an optical scanner (FOSDIC) which reads the information onto magnetic computer tapes. A computer edit program operates on these tapes to check further for completeness and consistency of the data. Certain entries are changed or edited according to fixed instructions. For instance, a person identified as the wife of a household head with a martial status of single is automatically changed to marital status of married, if there is also a head. Where single entries or whole questionnaires are missing, information is allocated for those persons. For example, if earnings were not reported for a male in a certain age group and occupation category who worked 40 or more weeks in 1969, the computer would supply to him the earnings of the last male processed living in the same area with the same age, occupation, and weeks worked characteristics.

Professional, technical and kindred workers

Farmers and farm managers

Managers, officials, and proprietors, except farm

Clerical and kindred workers

Sales workers

Craftsmen, foremen, and kindred workers

Operatives and kindred workers

Private household workers

Service workers, except private household

Farm laborers and foremen

Laborers, except farm and mining

Occupation not reported

For 1970, there are 12 major groups instead of 11 as in 1960. The new major group, entitled Transport Equipment Operatives, is made up of bus drivers, parking attendants, truck drivers, and others similarly employed. The categories comprising the new major group were moved from the 1960 major group Operatives and Kindred Workers, affording a basis for comparability.

A second revision (shown below) was the recasting of the arrangement of the major groups to reflect four broad occupational areas. The major groups and the occupational areas to which they relate are as follows:

1970 Major Occupational Groups Areas    Occupational Areas

Professional, technical, and kindred workers    White collar workers
Managers and administrators, except farm
Sales workers
Clerical and kindred workers

Craftsmen and kindred workers    Blue collar workers
Operatives, except transport
Transport equipment operatives workers
Laborers, except farm

Farmers and farm managers    Farm workers
Farm laborers and farm foremen

Service workers, except private household    Service workers
Private household workers

A third revision to the major groups relates to the processing of the data. Individuals who did not report an occupation were allocated to a major group through an allocation matrix based on selected demographic and economic characteristics. Thus, major group totals in 1970 include persons allocated to the major groups.

Fourth, instead of having the categories within each major group listed alphabetically, sub-grouping, or occupation families, have been established in several major groups. For example, the service workers group, to clarify its content, has been reclassified into 5 subcategories -- cleaning service, food service, health service, personal service, and protective service.

The Classified Index of Occupations to be used in the 1970 census is scheduled to be published this year. Copies will be available from the Superintendent of Documents of the Government Printing Office. Also, see the Statistical Reporter, December 1969, for a relevant article and occupations listing.