After the 1990 census, members of Congress expressed concern about the perceived adverse effect of the long-form questionnaire on the completeness of census response. In 1990, 29 percent of households that received the long form failed to mail back their form, compared with 24 percent of households that received the short form (National Research Council, 2004b:100), and some thought that this differential contributed to the poorer coverage of the population in 1990 in comparison with 1980. Other members of Congress were interested in more frequent estimates for small areas of such long-form-sample statistics as the percentage of school-age children in poverty for use in allocating federal funds to states and localities. Consequently, in 1994, the Census Bureau formed a staff to implement a continuous measurement design similar to that proposed by Kish in a few test sites, so that it could be evaluated as a replacement for the long-form sample in 2000. Renamed the American Community Survey, a questionnaire similar to the long form was fielded in four counties in 1996.5
The decision was made in the mid-1990s to retain the long-form sample in 2000 and to implement the ACS on a gradual basis, so that it could be further tested and compared with the 2000 census results. The goal was to conduct a short-form-only census in 2010 and to fully implement the ACS so that it could provide estimates for small areas that were about as precise as long-form-sample estimates for small areas by accumulating samples over 5 years. However, very early in the development process, rising costs led to a decision to scale back the originally planned sample size of 500,000 housing units per month to a sample of 250,000 housing units per month (National Research Council, 1995:127).
The original 4 ACS test sites were gradually increased to include 36 counties in 31 sites for the years 1999–2004 (see U.S. Census Bureau, 2003). In addition, the C2SS was fielded as an experiment in more than one-third of U.S. counties by using the monthly ACS data collection design and a questionnaire very similar to the long form. Cumulated over the 12 months of 2000, the C2SS, including the test sites, obtained responses from about 587,000 housing units; it demonstrated the feasibility of conducting an ACS nationwide and at the same time as the decennial census (U.S. Census Bureau, 2001). Similar nationwide test surveys were fielded in 2001–2004. In January 2005, full implementation of the ACS was inaugurated for the first month’s sample of 250,000 housing units; and in January 2006, group quarters residents were added to the ACS. Plans are to proceed with a short-form-only census in 2010.