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Central Distributor SASD: Description of Data Elements

PL_UIC2003 - Patient location: Urban Influence Codes, 2003
Documentation Sections:
General Notes
Uniform Values
State Specific Notes
General Notes

The 2003 version of the Urban Influence Codes (UIC) emphasizes the relationship of outlying counties to major metropolitan areas. Counties are subdivided into 12 categories distinguished by three features: population size in census-defined urbanized areas, adjacency to metropolitan or micropolitan areas, and the size of those adjacent communities. To be adjacent, counties must be contiguous and have at least 2% of the resident labor force commuting to a central metropolitan county.

A county-based system such as UIC, which attempts to describe the diversity in settlement patterns in a relatively large area by a single number, may not provide an accurate depiction. However, because county boundaries don't change much, every county will be represented by a measure, even after an extended period of time.

UIC were developed at the U.S. Department of Agriculture's Economic Research Service, as a refinement of the Office of Management and Budget (OMB) Core-Based Statistical Area (CBSA) definition. They are based on population and commuting information from the 2000 census and the OMB 2003 CBSA definitions. Additional information about the UIC classification scheme is available on the Internet at

The name of this HCUP data element and the version of the categorization have changed over time:

  • Starting in the 2014 HCUP databases, the classification of counties is based on the 2010 Census and the OMB 2013 Core Based Statistical Area (CBSA) definitions.
  • Starting in the 2013 HCUP databases, the data element is PL_UIC.
  • Between 2003 and 2012, the data element name was PL_UIC2003 and the classification of counties was based on the 2000 Census and the OMB 2003 CBSA definitions.
  • In 2002, the data element name was PL_UIC and the classification of counties was based on the 1990 Census and the OMB 1993 Metropolitan definitions.
  • This information was not included on the HCUP databases prior to 2002.
Uniform Values
VariableDescriptionValueValue Description
PL_UIC2003Patient location: Urban Influence Codes, 20031Metro - Large metro area of 1 million residents or more
2Metro - Small metro area of less than 1 million residents
3Non-Metro - Micropolitan adjacent to large metro
4Non-Metro - Noncore adjacent to large metro
5Non-Metro - Micropolitan adjacent to small metro
6Non-Metro - Noncore adjacent to small metro with own town
7Non-Metro - Noncore adjacent to small metro no own town
8Non-Metro - Micropolitan not adjacent to a metro area
9Non-Metro - Noncore adjacent to micro with own town
10Non-Metro - Noncore adjacent to micro with no own town
11Non-Metro - Noncore not adjacent to metro or micro with own town
12Non-Metro - Noncore not adjacent to metro or micro with no own town
State Specific Notes



Internet Citation: HCUP Central Distributor SASD Description of Data Elements - All States. Healthcare Cost and Utilization Project (HCUP). May 2024. Agency for Healthcare Research and Quality, Rockville, MD.
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Last modified 5/22/24