The White House Office of Management and Budget published new statistical area delineations last month based on updated Census data.

If you’ve heard the term “metro area” used in news stories, statistics or other conversations, then pay attention; the counties included in some metros have changed.

“Metro” is shorthand for Core-Based Statistical Area (CBSA) and they are revised every five years. This round of updates comes after incorporating data from the 2020 Census Urban Area boundaries and new commuting flow data from the American Community Survey.

Revisions to the boundaries are noteworthy because they are included in many federal data products and are used for determining eligibility for some government programs. The changes were announced on July 21, 2023, by the Office of Management and Budget (OMB), which is the agency that oversees the delineation process.

A CBSA groups counties based on population and economic interaction with surrounding counties. There are two types:

• Metropolitan Statistical Areas are centered around counties containing a census-defined urban area with a population of 50,000 or more
• Micropolitan Statistical Areas are centered around counties containing a census-defined urban area with a population of at least 10,000

Surrounding counties with a high degree of economic integration are then added to the core of the statistical area. To be considered an “outlying county” of a CBSA, at least 25 percent of the county’s workers need to work in the central county(-ies), or at least 25 percent of the county’s jobs must be filled by workers who live in the central county(-ies) of the CBSA.

A 2021 Federal Register notice outlined the methods used for delineating CBSAs in more detail.

An Overview of Changes in Tennessee

A Tennessee State Data Center review of the new delineation list found a total of 242 counties across the U.S. saw some kind of change this year. Among the revisions were changes for eight Tennessee counties.

The modifications included the addition of outlying counties to the state’s three largest metro areas: Nashville, Memphis and Knoxville (Table 1).

While there were no new Metropolitan Statistical Areas in Tennessee, two neighboring Micropolitan areas were added in the South-Central part of the state (Table 2). Fayetteville, TN (Lincoln County) is the first new micropolitan area. Winchester (Franklin County) formed a second new micropolitan area after being split off from the Tullahoma-Winchester micropolitan area.

Two micropolitan areas were dropped in this year’s delineations – both counties had urban areas which fell under the 10,000-person minimum threshold, but both were also notable for different reasons (Table 3).

The Dayton, TN (Rhea County) micropolitan area had an urban population of 9,688 people in 2020, which fell below the required minimum. Part of the area’s decrease was the result of undercounts at Bryan College resulting from COVID-related dormitory closures in March 2020. That undercount of 352 people, which was recently acknowledged by the Census Bureau in a post-2020 Census review, would have been sufficient to push the community over the 10,000 person threshold.

Brownsville, TN (Haywood County) was the second micropolitan area to be dropped. The county’s urban population of 9,621 people was also just under the 10,000 person minimum. That likely came as a result of new Census Bureau urban area delineation procedures designed to reduce the land area and population that is considered urban in the country.

The planned opening of a Ford Assembly plant in Haywood County is likely to boost both the county’s urban population and economic interaction with surrounding counties. That could see the areas regaining a micropolitan or outlying county status when the 2028 list is released.

The next comprehensive five-year update will occur in late 2028. They could include methodology changes related to the use of commuting data from the American Community Survey (ACS) as the sole measure of county-to-county economic interaction. Concerns that the 2021-2025 ACS Commuting Flows Data could be adversely impacted by travel-activity changes related to COVID-19 sparked the consideration.

What Is the Effect of the New Changes?

It’s not immediately clear that there is a practical impact related to the elimination of two micropolitan areas in Tennessee. Examples of state or federal program eligibility tied to micropolitan area status were not immediately evident.

The same is true of statistical products offered by the Bureau of Labor Statistics and the Bureau of Economic Analysis. Those agencies cluster some of their data offerings around Metropolitan Statistical Areas, but not around their smaller micropolitan counterparts; instead opting for county-level releases.

But the fact that the balance of the state’s existing MSAs remains in place is good news for Tennessee cities and counties. Those boundaries are important for statistical products and program eligibility.

Examples of potentially affected programs include:

• BLS Current Employment Statistics (State and Metro Area) only provides employer survey data for Metropolitan Statistical Areas
• The Community Development Block Grant program, an important source of housing and infrastructure funds, currently uses the MSA delineations based on the 50,000-person urban area standard for community eligibility; areas below this population threshold participate in a state-led program.

There are also several Tennessee state statutes that refer to the boundary and the OMB 50,000-person standard.