Due to the success of the mail-out/mail-back questionnaire in 1970 the program was expanded for 1980 with about 95 percent of the U.S. population now enumerated in this manner.
The 1980 short form contained 7 population questions and 11 housing questions; the long form contained an additional 26 population and 10 housing inquiries. A question on Spanish or Hispanic origin or descent was added to the 100-percent questions for the first time; in 1970 this question was asked of only 5 percent of the population.
The 1980 census also included two small surveys. The Components of Inventory Change Survey obtained information on the number and characteristics of housing units that changed or stayed the same between 1973 and 1980. The Residential Finance Survey collected data on mortgages, shelter costs, selected housing characteristics and owner characteristics.
An extensive public service advertising campaign directed by the Census Bureau's Census Publicity Office, which was established in 1978, focused on increasing the public's awareness of the census and encouraging people to complete and mail back their questionnaires. The Census Bureau secured the free services of the Advertising Council, which in turn hired the firm of Ogilvy & Mather to develop the campaign.
Additionally, the Census Bureau made a special effort to enumerate historically undercounted groups during two programs, "M-Night" ("M" for mission) and "T-Night" ("T" for transient). On M-Night, specially trained enumerators counted people staying in homeless shelters, soup kitchens, bus and rail stations, dormitories, and others. On T-Night, the enumeration focused on hotels and motels with permanent residents.
The Census Bureau developed the State Data Center Program to simplify public access to data available on computer tapes. Agreements between state governors and the director of the Census Bureau committed the agency to provide free copies of any Census Bureau electronic and printed information and products to the states; the states, in turn, agreed to develop a network of affiliate organizations (state executive departments, chambers of commerce, councils of governments, university research departments or libraries) by which census information would be delivered to local users. By the mid-1980's all states were participating in the program, which encompassed about 1,200 state and local organizations.
Demographic analysis of the 1980 census showed that once again the census, despite reaching the overwhelming majority of people in the United States, undercounted the population, this time by about 1.2 percent. More troubling, the estimated net undercount rate for African Americans was 3.7 percentage points higher than that for all other races combined.
Before the enumeration process had finished, the city of Detroit sued, demanding that statistical adjustment be used to compensate for those estimated by the Census Bureau to have been missed or improperly counted. Shortly thereafter, several other states and localities, including the city and state of New York, also filed suit. The Census Bureau announced in the fall of 1980 that it did not plan to adjust its population totals using statistical methods because it could not be sure of the number and distribution of illegal aliens and other undercounted groups.
The New York suit would eventually become the most prominent case; a federal district court ruled in the plaintiffs' favor in late 1980, ordering the Census Bureau to adjust its numbers to correct for the undercount. The Supreme Court stayed this and other rulings in December 1980, allowing the Census Bureau to report its unadjusted figures to the president. A federal appeals court finally ruled, in 1987, that the census figures should not be adjusted to account for the undercount because the Census Bureau's decision not to adjust was not arbitrary and capricious.