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The 2007 American Community Survey (ACS) 1-year data release provides data products for a set of geographic areas with a population of 65,000 or more. The ACS combines samples across multiple years to produce and publish multiyear estimates for smaller geographic areas.. The 2005 - 2007 ACS 3-year data release provides data products for geographic areas with populations of 20,000 or more. The population sizes for both these 1-year and 3-year data products are based on the July 1, 2007 population estimates from the Census Bureau's Population Estimates Program. In the future, areas with population of less than 20,000 will have access to ACS data from 5-year estimates.
The Census Bureau strives to produce information for geographic areas that are useful to a wide spectrum of data users. For example, the Census Bureau presents data summaries for the nation's many legal and administrative entities such as states (including the District of Columbia and Puerto Rico), American Indian and Alaska Native areas, counties and municipios, minor civil divisions (MCDs), incorporated places, and congressional districts. Data products are also available for other geographic entities. In cooperation with state and local agencies, the Census Bureau identifies and delineates geographic entities referred to as, "statistical areas." These include census regions and divisions, urbanized areas (UAs) and zonas urbanas, metropolitan and micropolitan statistical areas, census designated places (CDPs), and Public Use Microdata Areas (PUMAs). In addition, data are available for 15 geographic components. A geographic component is the portion of a geographic area (e.g. state) that has a location-based designation such as "in a rural area" or "in a metropolitan area".
The Census Bureau released 2007 ACS data for over 6,500 geographic areas that met the 65,000 or more population threshold for 1-year estimates. On December 9th, the Census Bureau releases ACS data for over 13,500 geographic areas that meet the 20,000 or more population threshold for the 3-year estimates. For many types of geographic areas, the release of 3-year estimates allows a much larger number of areas to receive estimates. Table 1 shows the types of geographic areas that are published in the ACS 1-year and 3-year data products, and includes information about the proportion of each type of geographic area that will receive 1-year, 3-year, and 5-year estimates; areas receiving only 3-year and 5-year estimates; and areas only receiving 5-year estimates. Table 2 provides similar information for the Puerto Rico Community Survey (PRCS).
| Types of Geographic Areas | Total Number of Areas | Percent of Total Areas Receiving 1-year, 3-year, & 5-year Estimates | Percent of Total Areas Receiving 3-year & 5-year Estimates Only | Percent of Total Areas Receiving 5-year Estimates Only |
|---|---|---|---|---|
| States and District of Columbia | 51 | 100.0 | 0.0 | 0.0 |
| Congressional Districts | 435 | 100.0 | 0.0 | 0.0 |
| Public Use Microdata Areas 1 | 2,071 | 99.9 | 0.1 | 0.0 |
| Metropolitan Statistical Areas | 363 | 99.4 | 0.6 | 0.0 |
| Micropolitan Statistical Areas | 576 | 24.3 | 71.2 | 4.5 |
| Counties and county equivalents | 3,141 | 25.0 | 32.8 | 42.2 |
| Urban areas | 3,607 | 10.4 | 12.9 | 76.7 |
| School Districts (Elementary, Secondary, and Unified) | 14,120 | 6.6 | 17.0 | 76.4 |
| American Indian Areas, Alaska Native Areas, and Hawaiian Home Lands | 607 | 2.5 | 3.5 | 94.1 |
| Places (cities, towns, and Census Designated Places) | 25,081 | 2.0 | 6.2 | 91.8 |
| Townships and villages (Minor Civil Divisions) | 21,171 | 0.9 | 3.8 | 95.3 |
| ZIP Code tabulation Areas | 32,154 | 0.0 | 0.0 | 100.0 |
| Census tracts | 65,442 | 0.0 | 0.0 | 100.0 |
| Census block groups | 208,801 | 0.0 | 0.0 | 100.0 |
1 When originally designed, each PUMA contained a population of about 100,000. Over time, some of these PUMAs have gained or lost population. However, due to the population displacement in the greater New Orleans areas caused by Hurricane Katrina in 2005, Louisiana PUMAs 1801, 1802, and 1805 no longer meet the 65,000-population threshold for 1-year estimates. With reference to PUMS data, records for these PUMAs were combined to ensure ACS PUMS data for Louisiana remain complete and additive.
Referring to Table 1, of the 3,141 counties in the United States, only 25.0 percent are large enough to receive 1-year, 3-year, and 5-year estimates. An additional 32.8 percent will receive 3-year and 5-year estimates. About 42.2 percent of all counties will receive only 5-year estimates. Data for Zip Code Tabulation Areas and Census tract and block groups are only released in the form of 5-year estimates.
For additional information about the specific areas that receive ACS 1-year and 3-year estimates, see the 2005-2007 Data Product Details Web page.
| Type of Geographic Area | Total Number of Areas | Percent of Total Areas Receiving 1-year, 3-year & 5-year Estimates | Percent of Total Areas Receiving 3-year & 5-year Estimates Only | Percent of Total Areas Receiving 5-year Estimates only |
|---|---|---|---|---|
| Puerto Rico | 1 | 100.0 | 0.0 | 0.0 |
| Public Use Microdata Areas | 30 | 100.0 | 0.0 | 0.0 |
| Metropolitan Statistical Areas | 8 | 100.0 | 0.0 | 0.0 |
| Micropolitan Statistical Areas | 5 | 0.0 | 60.0 | 40.0 |
| Municipios | 78 | 15.4 | 67.9 | 16.7 |
| Urban areas | 18 | 55.6 | 16.7 | 27.8 |
| School Districts (Elementary, Secondary and Unified) | 1 | 100.0 | 0.0 | 0.0 |
| Places (cities, towns, and Census Designated Places) | 225 | 3.1 | 4.4 | 92.4 |
| Census tracts | 861 | 0.0 | 0.0 | 100.0 |
| Census block groups | 2,477 | 0.0 | 0.0 | 100.0 |
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