Data Dictionary: Census 1980
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Survey: Census 1980
Data Source: U.S. Census Bureau
Table: T31. Age By Language Spoken at Home and Ability to Speak English [19]
Universe: Persons 5 Years and Over
Relevant Documentation:
Excerpt from: Social Explorer; U.S. Census Bureau; Census of Population and Housing, 1980: Summary Tape File 3 [machine-readable data file] / conducted By the U.S. Bureau of the Census. Washington: Bureau of the Census [producer and distributor], 1982.
 
Age
Age at last birthday, i.e., number of completed years from birth to April 1, 1980, based on replies to a question on month and year of birth. This item was asked on a complete-count basis.

Because of the central importance of the data on age, the question contains redundancies. The age entry on the basic tape record is derived from the FOSDIC entries of quarter and year of birth. For those persons who do not provide this information but who do provide "age at last birthday," the census enumerator or clerk uses an equivalency table to mark the appropriate FOSDIC circles. The item "age at last birthday" is used only secondarily because of the tendency of some people, in reporting their ages, to round off to "0" or "5" (and to report even rather than odd numbers). The write-in entries of month and year of birth are requested because some people have difficulty with (and therefore skip) the FOSDIC marking system in this question.

Age is tabulated by single years of age and by many different groupings such as 5-year age groups. Basic records identify single years (and quarter years on sample basic records) to 112. Public-use microdata samples show single years and quarters to 99, and 100 years or more.

Median Age
Calculated as the value which divides the age distribution into two equal parts, one-half the cases falling below this value, one-half above. Median age is computed from the age intervals or groupings shown in the particular tabulation, and thus a median based on a less detailed distribution may differ slightly from a corresponding median for the same population based on a more detailed distribution. If the median falls in the terminal category, e.g., 75 years and over, the median is shown as the initial age of the category with a plus sign, e.g., 75+.

Limitations
In previous censuses, undercoverage of the population has been associated with age. Young adults, especially Black males, were missed at a higher rate than other segments of the population. The same is true of centenarians.

Historical comparability
Age data have been collected in each census since 1790. Counts in 1970 and 1980 for persons 100 years old
and over were substantially overstated.

See also: "Age of Householder".

Excerpt from: Social Explorer; U.S. Census Bureau; Census of Population and Housing, 1980: Summary Tape File 3 [machine-readable data file] / conducted By the U.S. Bureau of the Census. Washington: Bureau of the Census [producer and distributor], 1982.
 
Language Spoken At Home
Persons who speak a language other than English at home were asked to report the language spoken, as well as their proficiency in English (see Language Usage and Ability to Speak English). This item was asked on a sample basis.

Respondents were instructed to report the language spoken most often, for persons speaking two or more non-English languages at home, or the first language learned, where the language spoken most often could not be determined.

The write-in entries of the language spoken were coded in census processing offices into 387 categories which arerecorded on basic records and public-use microdata files. Tables in PC30-1-C reports include the following categories:

English only, Chinese, French, German, Greek, Italian, Philippine languages, Polish, Spanish, other specified language, and unspecified language.

Data on languages spoken in the home are typically presented separately for persons 5 to 17 and 18 years old anti over. These data should not be interpreted as the number of people who are able to speak specified languages, since this question counts only persons who speak a language other than English at home.

The reported number of persons who speak a language other than English at home may be inflated slightly by a processing error. The total number of persons who speak a language other than English is inflated by approximately 0.4 percent nationwide. There is some geographic variation in the frequency of the errors, but no substantial spatial clustering has been discovered. Subsequent data products (STF 4, STF 5) will correct these errors, and thus may disagree with the estimates provided in STF 3.

Historical comparability
These data on current language are not comparable to questions asked in 1950 and 1970 on mother tongue, i.e., language other than English spoken in the person's home when he or she was a child. In 1970, Spanish mother tongue was a major determinant in the classification of "persons of Spanish heritage."

See also: "Language Usage and Ability to Speak English".

Excerpt from: Social Explorer; U.S. Census Bureau; Census of Population and Housing, 1980: Summary Tape File 3 [machine-readable data file] / conducted By the U.S. Bureau of the Census. Washington: Bureau of the Census [producer and distributor], 1982.
 
Language Usage and Ability to Speak English
Persons 5 years old and over are classified by whether they speak a language other than English at home, and, if so, by how well they speak English. Responses for persons under 5 are not tabulated. This item was asked on a sample basis.

Speak only English at home
Persons who always speak English at home. Includes persons who may speak a language other than English at school or elsewhere, but not at home, and persons whose usage of another language at home is limited to a few expressions or slang.

Speak a language other than English at home
Persons who speak a language other than English at home, even if English is spoken more frequently than the other language. They are further classified by level of English language ability:

Speak English very well
Persons who have no difficulties speaking English.

Speak English well
Persons who have only minor problems which do not seriously limit their ability to speak English.

Speak English not well
Persons who are seriously limited in their ability to speak English.

Speak English not at all
These datatypically are presented separately for persons 5 to 17 years old (school-age population) and for persons 18 years old and over, to aid the assessment of needs for bilingual education and other services.

Historical comparability
The question on current language spoken at home replaces a question asked in 1960 and 1970 on mother tongue, i.e., language other than English spoken in the person's home when he or she was a child. In 1960, mother tongue was asked only of foreign-born persons. In 1970, mother tongue was asked of all persons and vas a major determinant in the classification of "persons of Spanish heritage."

The focus on current language rather than mother tongue is a significant departure from previous censuses. The question on ability to speak English is being asked for the first time in 1980.

See also: "Language Spoken At Home".