The full implementation of data collection for the American Community Survey (ACS) in 2005–2006 is a historic event for the nation’s statistical system. Based on over 10 years of research and development by the Census Bureau, the ACS is intended to replace the decennial census long-form sample as a source of regularly updated demographic and socioeconomic information on the population and housing of states, counties, cities, and other governmental and statistical areas.

The panel’s assessment is that the ACS will deliver on its promise to provide more timely, frequent, and complete information than the longform sample. Given the survey’s continuous design, however, ACS estimates are not the same as the long-form-sample estimates for a point in time (Census Day, April 1); instead, they represent annually updated period estimates based on 12 months of data and (once sufficient years of data are accumulated) 36 and 60 months of data. Only 60-month estimates (5-year period estimates) will be available for the smallest areas. ACS estimates also have significantly higher sampling errors than the corresponding longform-sample estimates, a feature of particular concern for the smallest areas (small counties, cities, towns, villages, American Indian and Alaska Native areas, and school districts, as well as census tracts and block groups).

While the ACS continuous design presents challenges to users, it also affords opportunities to develop applications that go far beyond what was possible with the long-form sample. Some innovative uses of the ACS will be easier to implement than others. In the same vein, some uses of the ACS to replace long-form-sample data will be easier to implement than others.