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  Census > ACS Main > About the Data (Methodology) Main > ACS 1999-2001 and Census 2000 Comparison Study

About the Data (Methodology) Main

ACS 1999-2001 and Census 2000 Comparison Study

Multiyear Estimates Study

Data Collection & Processing

Evaluation Report Series

  »  2003 ASA Documents
  »  Working Papers

2006 ACS Content Test
  » Report Series



The American Community Survey (ACS) is a new Census Bureau initiative which is key to the re-engineering process of the 2010 Census. In 1994, the Census Bureau, began to develop and test the feasibility of producing long form data using the ACS design on an annual basis. The ACS design has continued its development over the last decade. The pilot study started in 1996 with 4 counties. Initial results were highly successful. To ensure acceptance of the ACS by the data user community the Census Bureau expanded data collection activities to 36 counties in 1999. Data collection activities in the 36 counties continued from 1999 through 2001.

County Selection

The counties were selected based on a set of pre-specified criteria. These factors include: the size of the county's population, the proportion of the population in areas classified as hard to enumerate (based on mail response rates in the 1990 census), and the growth or decline in population since 1990. In addition, the list included counties that varied along important dimensions such as dominant industry, classification as rural/urban/suburban, racial/ethnic distribution, presence and number of mobile homes, large numbers of non-city style addresses, seasonal populations, and presence of American Indian reservations.

Data Comparison / Quality Measures

The data collected during the three years period provided the basis for a statistical comparison of the ACS and the Census 2000 long form estimates. The goal of the comparison project is to understand and assess differences between the estimates. Comparisons are made of specific population and housing subjects such as income, education, and poverty for small areas and population subgroups. In addition, a set of quality measures were also derived to help understand the completeness of the data used to produce the census sample and ACS estimates.

This web site provides:

  • online comparison profiles at the county and tract level1
  • online quality measure tables at the county level
  • supporting documentation
  • downloadable data sets at the county and tract level from the Census and the ACS,
  • downloadable quality measure datasets at county and tract level
  • analytical reports

To begin reviewing the data online, please go to Online Data and choose a county.

1Except for Fort Bend and Harris counties in Texas. For these two counties the data sets are provided at the county level and for locally defined neighborhoods. Census tracts are the building units for the neighborhoods.

Source: U.S. Census Bureau  |  American Community Survey Office  |  Page Last Modified: September 30, 2008