We were recently asked by a customer if it is possible to use CDXZipStream, our Microsoft Excel add-in for address and zip code analysis, to determine whether a zip code is in a rural area. Here’s our response:
A fairly stringent determination of rural zip codes, which can be done easily using CDXZipStream, is based on whether the zip code is part of a Core Based Statistical Area, or CBSA. CBSA’s are defined by the Office of Management and Budget as urban areas; a metropolitan area contains a core urban area of 50,000 or more population, and a micropolitan area contains an urban core of at least 10,000 (but less than 50,000) population. Each metro or micro area consists of one or more counties and includes the counties containing the core urban area, as well as any adjacent counties that have a high degree of social and economic integration (as measured by commuting to work) with the urban core. Based on the 2010 Census, approximately 95% of the U.S. population lives in either a micropolitan or metropolitan CBSA. If a zip code is not associated with a CBSA then, it is a good assumption that it is in a non-urban, or rural area. Using the CDXZipCode premium feed (available in CDXZipStream Demographic version and higher), request the data field “CBSA”; if the returned value is "N/A", then the zip code is not associated with any CBSA and you can assume that it is rural.
The attached map shows the current coverage of Core Based Statistical Areas in the U.S. and Puerto Rico:
Using an alternative U.S. Census Bureau definition, rural areas comprise open country and settlements with fewer than 2,500 residents. All other (urban) areas are of two types—urbanized areas and urban clusters—identical in the criteria used to delineate them but different in size. The Census Bureau defines an urbanized area wherever it finds an urban nucleus of 50,000 or more people. They may or may not contain any individual cities of 50,000 or more. Urban clusters have a population of at least 2,500 but less than 50,000 persons. Using these criteria, about 16% of the U.S. population lives in what is considered to be rural areas, based on the results of the 2010 Census. You can download from the Census website relationship files showing which ZCTA’s (the Census Bureau’s approximation of zip codes) correspond to urban and non-urban (rural) areas.
You may also want to consider population density as a rough measurement of urban/rural characteristics, Population density can be easily calculated by dividing the total population of the zip code by the land area. Again, using the CDXZipCode Premium feed, request the data fields “Population” and “LandArea” and then use Microsoft Excel to perform the calculation. Keep in mind, however, that population density provides only a partial picture, since there may be non-residential areas with low population counts that exist in the middle of urban centers.