The 1990 census mailout procedures had not included an advance letter; however, a reminder postcard was delivered to all addresses in both mailout/ mailback and update/leave areas. Responding by the Internet (which did not exist) was not an option. The questionnaire and mailing package were designed not to facilitate response as much as to permit data processing with the technology used in the 1960–1980 censuses (see “Data Processing,” below).
Overall, the mailing strategies used in the 1990 census did not appear to help mail response. The mail response rate declined from 75 percent in 1980 to 65 percent in 1990; the mail return rate declined from 81 percent in 1980 to 74 percent in 1990.
Because not all households will mail back a form and because many addresses to which questionnaires are delivered will turn out to be vacant or nonresidential, the 2000 census, like previous censuses, included a large field follow-up operation (see Thompson, 2000). Over 500 local census offices (LCOs) were set up across the country, which reported to 12 regional census centers. The LCOs were responsible for hiring the temporary enumerators and crew leaders who would be needed to conduct follow-up operations. In update/leave areas, enumerators were hired to deliver questionnaires prior to Census Day and to return to follow up nonresponding households. LCOs also carried out operations to enumerate special groups, such as group quarters residents, transients, and the homeless.
In anticipation of possible difficulties in hiring and also the possibility that the mail response rate would decline from 1990, LCOs were authorized to recruit aggressively in advance of Census Day, to hire more enumerators than they thought would be needed, and to pay above-minimum wages (which differed according to prevailing area wages). Most offices were successful in meeting their hiring goals before the first follow-up operations began in mid-April 2000.
Follow-up operations were carried out in two separate stages, discussed below. The first stage, conducted in April-June, was the nonresponse followup, designed to obtain a questionnaire from every nonresponding unit in the mailback universe (or to determine that an address was vacant or nonresidential). The second stage, conducted in June-August, was coverage improvement follow-up (CIFU), which included specific operations designed to check and supplement NRFU. Several operations included in CIFU for 1990 were dropped for 2000.