April 2004  issue of AmberWaves

Amber Waves Heading

United States Department of Agriculture | Economic Research Service Search   GO!  
Current Issue
All Issues
spacer Amber Waves Home

 

Up Front
  Feature Articles

Findings

Gleanings
  Data Feature

Indicators

Profiles

 

About Amber Waves

  spacer images

ERS logo
USDA's Economic Research Service

 

AmberWaves April 2004 > Indicators > Behind the Data

Print this page Print | E-mail this link E-mail | Bookmark & Share Bookmark/share | Translate this page Translate | Text only Text only | resize text smallresize text mediumresize text large
title "Indicators"

indicators tabbehind the data tabresearch areas tabon the map tab

spacer

Developing a County-level Measure of Urban Influence


Linda Ghelfi

Timothy Parker


An area’s geographic context has a significant effect on its development. Economic opportunities accrue to a place by virtue of both its size and its access to larger economies. Population size, urbanization, and access to larger communities are often crucial elements in county-level research. To advance such research, ERS developed a set of county-level urban influence categories that captures some differences in economic opportunities.

County Definitions

Large metro: In areas with at least 1 million residents

Small metro: In areas with less than 1 million residents

Micropolitan: Areas containing an urban core of at least 10,000 residents

Noncore: Counties without an urban core of at least 10,000 residents

The 2003 Urban Influence Codes divide the 3,141 counties, county equivalents, and independent cities in the United States into 12 groups. Counties are first divided into metropolitan (metro) and nonmetropolitan (nonmetro) categories according to the official classification announced by the Office of Management and Budget (OMB) in June 2003, based on population and commuting data from the 2000 Census of Population. Metro counties are then divided into two groups by the size of the metro area they are in—large and small (see box, “County Definitions”). Nonmetro counties are divided into 10 groups, first by micropolitan (micro) versus noncore status, then by proximity to metro- or micro-areas.

Nonmetro micro counties are divided into three groups by their adjacency to metro areas—adjacent to a large metro area, adjacent to a small metro area, and not adjacent to a metro area. Nonmetro noncore counties are divided into seven groups by their adjacency to metro or micro areas and whether or not they have their “own town” of at least 2,500 residents.

Nonmetro counties are defined as adjacent if they abut a metro area (noncore counties may also abut a micro area) and have at least 2 percent of employed persons commuting to work in the core of the metro area (or in the micro area). When a nonmetro county was adjacent to more than one metro (or micro) area, it was designated as adjacent to the area to which the largest percentage of its workers commuted.

In concept, the 2003 Urban Influence Codes are comparable with those of earlier decades. However, as a result of changes in metro area delineation procedures and in rural and urban area measurement, our new codes are not fully comparable with those of earlier years. Those changes are explained on the ERS website at: www.ers.usda.gov/briefing/rurality/newdefinitions/.

2003 Urban Influence Codes

County type

Number of
counties

2000
population

Population per
sq. mile

Metropolitan counties:

In large area of at least 1 million residents

413

149,224,067

558

In small area of less than 1 million residents

676

83,355,873

132

Nonmetropolitan counties:

Micropolitan counties—

Adjacent to large metro

92

5,147,233

55

Adjacent to small metro

301

14,668,144

51

Not adjacent1

282

9,139,821

27

Noncore counties—

Adjacent to large metro

123

2,364,159

27

Adjacent to small metro with own town

358

7,855,590

24

Adjacent to small metro with no own town

185

1,879,264

6

Adjacent to micro with own town2

201

3,227,833

17

Adjacent to micro with no own town2

198

1,313,175

7

Not adjacent to metro or micro with own town1

138

2,247,189

5

Not adjacent to metro or micro with no own town

174

999,558

4

Total

3,141

281,421,906

80

1 Micro counties that are not adjacent are often local trade centers. Nonadjacent-noncore counties with towns may be service centers for surrounding smaller counties, especially in less-populated areas of the Great Plains.

2 The micro area that a noncore county is adjacent to may itself be adjacent to a small or large metro area. This hierarchical commuting relationship is not reflected in the coding system.

 

PDF icon Get all Indicators in Adobe PDF Format (834 kb)

red leaf rounded colored spacer
red leaf

This article is drawn from...

rounded color spacer

All outlook reports
Get recent releases, links to the latest data, an outlook release calendar, outlook-related special reports, and a brief overview of the outlook for U.S. agriculture.

AO tables
Get the statistical indicators formerly provided in Agricultural Outlook magazine.