United States Census Bureau
The United States Census Bureau (USCB), officially the Bureau of the Census, is a U.S. DOC agency. It is responsible for conducting the U.S. Census.
Contents
Composition
The Census Bureau is overseen by the U.S. Department of Commerce.
The bureau is led by a director.
History
The Census Office was established in 1840.
In 1902, the Census Office was re-organized under the Department of the Interior.
The U.S. Department of Commerce and Labor was established in 1903 and the Census Office was again re-organized under it, and simultaneously renamed to the Census Bureau. When that department was split in 1913, the Census Bureau remained in the DOC.
Geographies
The bureau has standardized geographic classifications across their data products.
Blocks
Census blocks are the smallest area defined for the U.S. Census. They often follow actual city blocks.
Block definitions change every decade and cannot be tracked. Furthermore, public data is not provided for blocks.
To create some ability to report on and track blocks, they are aggregated into block groups. These usually include between 250 and 550 housing units.
Tracts
Census tracts are intended to be demographically and economically homogeneous areas with a population of around 4,000. They often follow visible features like rivers.
Area definitions are reviewed every decade for subdivision, but generally they can be tracked over time.
Core Based Statistical Areas
Core Based Statistical Areas (CBSA) are also sometimes known as metropolitan statistical areas and micropolitan statistical areas. They are intended to address some of the weaknesses of other geographic definitions, such as homogeneous urban areas that have spread across county or state boundaries. As such, there are significant portions of the country with no defined areas, because existing geographies capture everything of interest.
These areas are created from one or more counties (or equivalent) anchored by an urban center. Each must have a population of 10,000. Adjacent counties that exist in the same economic sphere (especially as in a commuting labor force) are added to the area.
OMB is responsible for these definitions. The definitions originated in 2003; they were revised in 2013.
Public Use Microdata Areas
Public Use Microdata Areas (PUMA) are statistical geographic areas defined for the tabulation and dissemination of Census Bureau data.
These areas are mandatorily nested within state (or equivalent) borders. Wherever possible, they encompass entire CBSAs. They are however allowed to cross county borders if following a tract, as long as each division of a county meets a minimum population of 10,000.
Each PUMA must have a population of at least 100,000. Except where a high rate of population decline is predicted, the area is subdivided to maintain a population below 200,000.
State data centers (SDC) are responsible for these definitions, although there is significant cooperation and collaboration with state/municipal governments and other stakeholders.
ZIP Code Tabulation Areas
ZIP Code Tabulation Areas (ZCTA) approximate USPS ZIP codes. These are created to enable anonymized reporting of ZIP code-level data.
Usage
Language codes are standardized.
See the following pages for specific surveys and products.