Data Dictionary: Census 1980
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Survey: Census 1980
Data Source: U.S. Census Bureau and Social Explorer
Table: T8. Age (detailed version) [27]
Universe: Total population
Table Details
T8. Age (detailed version)
Universe: Total population
Variable Label
T008_001
T008_002
T008_003
T008_004
T008_005
T008_006
T008_007
T008_008
T008_009
T008_010
T008_011
T008_012
T008_013
T008_014
T008_015
T008_016
T008_017
T008_018
T008_019
T008_020
T008_021
T008_022
T008_023
T008_024
T008_025
T008_026
T008_027
Relevant Documentation:
Excerpt from: Social Explorer, U.S. Census Bureau; Census of Population and Housing, 1980 [United States]: Summary Tape File 1a [Computer file]. ICPSR version. Washington, DC: U.S. Dept. of Commerce, Bureau of the Census [producer], 1982. Ann Arbor, MI: Inter-university Consortium for Political and Social Research [distributor], 2002.
 
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.

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.

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."