Overview
The 2003 Urban Influence Codes form a classification scheme that
distinguishes metropolitan counties by size and nonmetropolitan
counties by size of the largest city or town and proximity to metro
and micro areas. The standard Office of Management and Budget (OMB)
metro and nonmetro categories have been subdivided into two metro
and 10 nonmetro categories, resulting in a 12-part county
codification. This scheme was originally developed in 1993. This
scheme allows researchers to break county data into finer
residential groups, beyond metro and nonmetro, particularly for the
analysis of trends in nonmetro areas that are related to population
density and metro influence.
An update of the Urban Influence Codes is planned for
mid-2013.