Description

A metropolitan area, or metro area, is a region consisting of a large urban core together with surrounding communities that have a high degree of economic and social integration with the urban core. For residents of metro areas, METAREA identifies the metro area of residence, contingent on varying delineations of metro areas across time and on variations in available geographic information and in confidentiality restrictions among samples.

METAREA is not available for 2012-onward ACS and PRCS samples or the 2010 census 10% sample. For information about variables that provide metro area codes for these samples, see the overview page: IPUMS USA Variables for Metropolitan Areas.

User Caution: Incompletely Identified Metropolitan Areas
In samples from 1960 to 2011 (excluding the 1970 and 1980 metro samples), METAREA only partially identifies the populations of many metro areas, and the unidentified portions can be considerably large, occasionally over 50%. Users should consult the Incompletely Identified Metropolitan Areas page, which lists the percent of each metro area's population that resided in excluded areas for each sample.

The reason for incomplete coverage is that the source data for these samples include no specific information about metro areas. The most detailed geographic information available is for 1980 county groups or for PUMAs, areas which occasionally straddle official metro area boundaries. If any portion of a straddling area's population resided outside a single metro area, the METAREA variable uses a conservative assignment strategy and identifies no metro area for all residents of the straddling area.

Users should not assume that the identified portion of a partly identified metro area is a representative sample of the entire metro area. In fact, because the unidentified population is located in areas that straddle the metro area boundaries, the identified population will often skew toward core populations and omit outlying communities. Also, weighted population counts for incompletely identified metro areas will be low by amounts ranging from 1 to 69% (since the unidentified individuals will not be counted as living in the metro area).

Metropolitan Area Delineations
Since 1950, the Bureau of the Budget (later renamed the Office of Management and Budget, or OMB), has produced and continually updated standard delineations of metropolitan areas for the U.S., defining each area as a county or a set of contiguous counties, or, for New England prior to 2003, as a set of cities or towns. In IPUMS samples for 1950 and later, the areas identified by METAREA generally correspond to contemporary OMB delineations, as were also used by the Census Bureau. For ACS samples through 2011, METAREA uses the 1999 OMB delineations, as were used for Census 2000 tabulations.

To delineate metro areas in pre-1950 samples, the general approach (used first by the creators of the 1940 PUMS and then by IPUMS for earlier samples) is to apply the 1950 OMB standards to historical statistics. One deviation from the 1950 standards is that all pre-1950 delineations are county-based, even in New England.

See the Comparability section for details on how delineations have changed over time and how confidentiality restrictions have affected METAREA's correspondence with standard delineations. For a listing of the counties associated with each metro area in each sample year, see the County Composition tables. For a complete record of OMB standards and changes since 1950, see the Census Bureau's historical delineations page.

The METAREA Code System
METAREA codes are based primarily on the 4-digit OMB codes of 1990 metropolitan areas but with adjustments to reflect hierarchical relationships among metro areas across time. For any group of metro areas that were at any time defined to be components of a single metro area together, the 4-digit METAREA codes were adjusted to use the same first 3 digits. E.g., the METAREA code for Fort Worth, TX, is 1921, which indicates that the area was, in some sample, included as part of the Dallas-Fort Worth, TX, metro area, which has a code of 1920. Similarly, in cases where the 1990 OMB codes of disjoint areas share the same first 3 digits, the METAREA codes were adjusted to be distinct through 3 digits. This system enables users to obtain relatively consistent samples for "top-level" metro areas across time by grouping records according to the first 3 METAREA digits.

However, when IPUMS assigned METAREA codes for the 2000 and ACS samples, the codes were not adjusted to reflect any new splits or mergers. E.g., between 1990 and 1999, the OMB delineations merged the Odessa and Midland, TX, metro areas (with codes of 5800 and 5040) into a single area (with a code of 5800). Maintaining the hierarchical structure of METAREA codes would have required changing some existing 1990-based codes (e.g., changing the Midland code from 5040 to 5801), but to maintain static codes for prior users of METAREA, no codes were changed. Therefore, the first 3 digits of METAREA codes do not consistently represent top-level groups for the 2000 and ACS samples.

The METAREA Label System
METAREA labels are generally based on the OMB names of 1990 metropolitan areas or on the standard names of other older areas that do not appear in the 1990 delineations. A METAREA label may include the names of any major central cities that were ever included in the identified area, including some cities that are associated with a different code in some samples. E.g., the METAREA code 1920 has a label of "Dallas-Fort Worth, TX," but in most samples, records for Fort Worth have a code of 1921 and not 1920.

This system ensures that the first label in each 3-digit METAREA group will properly describe the full extent of the general 3-digit code group, but it also causes ambiguities for the detailed 4-digit codes. In samples where a city name appears in the labels for 2 different codes, users should assume that the city is associated only with the higher-numbered code.

Alternative for Pre-1950 Samples: Metropolitan Districts
Prior to the introduction of the OMB's standard metropolitan areas in 1950, the Census Bureau had defined and tabulated statistics for metropolitan districts, which differ from metropolitan areas primarily in their use of minor civil divisions (cities, towns, etc.) as building blocks instead of counties. The METDIST variable identifies metropolitan districts for pre-1950 samples using criteria similar to those used by the Census in 1940. One advantage of METDIST relative to METAREA is that METDIST was constructed for the 1940 sample after confidentiality requirements were lifted for 1940 and is therefore more complete than METAREA for that year.

Comparability

Most of the changes in METAREA designations across samples correspond to official updates of metro area delineations. Such changes are meaningful for comparisons insofar as they correspond to real changes in metro area extents, and most do. But official delineations are built from relatively large, discretely-bounded areas (usually counties), and they change through discrete additions, subtractions, mergers, and divisions. In contrast, the "real" extents of metropolitan systems are fuzzy, varying by degrees, and their changes tend to be gradual. Therefore, all official changes in metro area delineations are, to some extent, arbitrary, with potentially misleading effects on measures of population change within metro areas.

Before interpreting any observed changes in population characteristics by METAREA, users should consult the County Composition tables to determine whether there have been any changes in a metro area's delineation. Where changes have occurred, users should consider to what extent the changes may have affected population size and composition. This is especially important in cases where two or more similarly sized population centers have at different times been included, and not included, in the same metro area (e.g., San Francisco and Oakland, CA; Odessa and Midland, TX; etc.).

A second significant complication for METAREA comparability is that, due to variations in confidentiality restrictions and in the geographic information available in public use samples, it is not possible to identify all residents of all metro areas in all samples, and these restrictions affect the representativeness of METAREA to varying degrees across samples and even among metro areas within samples. Most problematically, as noted in the Description section, the populations of many metro areas are only partially identified by METAREA in 1980 and later samples. Users of these samples should consult the Incompletely Identified Metropolitan Areas page to find the percent of each metro area's population that is excluded by METAREA codes for each sample.

The remainder of this section details how standards and restrictions vary across samples. Despite the many adjustments in official terminology and criteria noted below, the general concept of "metropolitan areas" that official delineations are intended to represent has remained essentially the same. As stated in the Census Bureau's Geographic Areas Reference Manual, p. 13-5, "Most of the changes in the standards have been minor and have not reflected signficant deviations from the concepts underlying the standards used for the 1950 census."

Terminology

OMB standards have used different terms to describe metro areas at different times:

• In 1950, the term was Standard Metropolitan Area (SMA).
• From 1960 through 1981, the term was Standard Metropolitan Statistical Area (SMSA).
• From 1983 through Census 2000, the term was Metropolitan Area (MA), which included free-standing Metropolitan Statistical Areas (MSAs), and Primary Metropolitan Statistical Areas (PMSAs), which grouped together form larger Consolidated Metropolitan Statistical Areas (CMSAs).

• With the 2003 definitions, the OMB established a more comprehensive concept of Core Based Statistical Areas (CBSAs), which include Metropolitan Statistical Areas and smaller Micropolitan Statistical Areas.

• Micropolitan Statistical Areas, which have an urban core of between 10,000 and 50,000 persons in size, are generally too small to be identified in public use microdata.
• The new Metropolitan Statistical Areas correspond in concept to the metropolitan areas of earlier standards, but they use a new code system and are entirely county-based (unlike earlier standards that based New England areas on towns and cities). For these reasons, among others, METAREA has not been extended to use the latest OMB standards. For information about other variables that provide metro area codes using later OMB standards, see the overview page: IPUMS USA Variables for Metropolitan Areas.

1950 and Earlier Samples

In 1950, an SMA is a county or group of contiguous counties (or county equivalents) that contained at least one city of 50,000+ residents. To be part of an SMA, a county either had to contain the 50,000+ city, or had to be metropolitan in character and integrated with a central city.

• To be considered metropolitan in character, a county had to

• either contain 10,000 nonagricultural workers, or 10 percent of the nonagricultural workers working in the SMA, or contain 50+ percent of its population in minor civil divisions that had a population density of 150+/square mile and were contiguous with the central city, and
• have at least 2/3 of its employed residents working in nonagricultural occupations.

• Criteria for integration with a central city include situations where:

• 15+ percent of the workers residing in the county worked in the county which contained the SMA's largest city, or
• 25+ percent of the workers employed in the county lived in the county which contained the SMA's largest city, or
• the monthly total of phone calls from the county to the county which contained the SMA's largest city was 4+ times as large as the county's number of phone subscribers.

For 1940 1% and 1950, SMAs are identified in METAREA only if the following confidentiality criteria are met:

• The SMA's 1980 population must be 100,000+.
• The state's non-metropolitan population must be at least 100,000 in 1980.
• The state's total non-identifiable population (resulting from the two previous rules) must be either zero or 100,000+ in 1980. (Four SMAs are defined but are not identified for this reason.)
• For SMAs that crossed state lines, the 100,000+ population threshold was applied to each state's portion of that SMA. If the portion within a particular state exceeded 100,000 residents, the SMA could be identified; if not, it remained confidential. Thus, some interstate SMAs are only partially identifiable.

There were two types of exceptions to these rules in the 1940 1% and 1950 samples:

• While the original 1940 PUMS identified the same set of metropolitan areas as the 1950 PUMS, the IPUMS suppresses those 1940 METAREAs that did not meet the requisite criteria for metropolitan status at that time (and codes them as non-metropolitan in the METRO variable as well). The following METAREAs were identified in the 1940 PUMS but are not identified in the IPUMS for 1940:

Albuquerque, NM	Muncie, IN
Baton Rouge, LA	Ogden, UT
Bay City, MI	Orlando, FL
Green Bay, WI	Pittsfield, MA
Greenville, SC	Raleigh, NC
Honolulu, HI	San Bernadino, CA
Lorain-Elyria, OH	Sioux Falls, SD
Lubbock, TX	Wichita Falls, TX

• SMAs in New England are treated differently in the 1940 and the 1950 PUMS. For 1940 (and earlier years), New England SMAs followed county lines, as they did elsewhere in the United States. For 1950, New England SMAs followed the boundaries of towns and cities. In some cases, this meant that a 1940 New England SMA contained a county (or counties) that was (were) split between two or more SMAs in 1950. Because of this, six SMAs are identified for 1940 but not for 1950: Lawrence, MA; Lowell, MA; New Bedford, MA; New Britain-Bristol, CT; Stamford-Norwalk, CT; and Waterbury, CT.

For the 1850-1930 samples, IPUMS defines SMAs by applying rules similar to the 1950 rules using historical census statistics. Specifically, an SMA is a county or group of contiguous counties that contained at least one city of 50,000+ residents. To be part of an SMA, a county either had to contain the central city, or had to be metropolitan in character and integrated with the central city.

• To be considered metropolitan in character, a county had to

• either contain 10,000 nonagricultural laborers, or contain at least one-tenth as many nonagricultural workers as worked in the county containing the central city of the SMA, or contain 50+ percent of its population in minor civil divisions that had a population density of 150+ persons per square mile and were contiguous to the central city, and
• have at least 2/3 of its employed residents working in nonagricultural occupations.

• For 1850 to 1930, the criterion for integration with the central city was that at least 25 percent of the county population resided in the central city of the metropolitan area.

1960
The 5% 1960 sample METAREA designations are based on 1960 OMB metropolitan area delineations. As in other samples, many metropolitan areas are only partly. See the Incompletely Identified Metropolitan Areas page for details.

The 1% public use microdata for 1960 provide no information for any geographic units smaller than states, so METAREA cannot be determined for this sample.

1970

1970 SMSAs were essentially the same as what were previously called SMAs. However, in 1970, there could be two or more contiguous cities of 15,000+ residents, with a combined population of 50,000+, rather than a single central city of 50,000+ residents. If adjacent counties each had a city of 50,000+ residents, and the cities were within 20 miles of one another, they were placed within the same SMSA, unless there was clear evidence that they should be separated. (This practice of combining counties with nearby large cities into a single SMSA seems to have been followed in the 1940 and 1950 PUMS as well, but the documentation for those years is not explicit.)

To be part of an SMSA in 1970, a county either had to contain the central city (or cities), or, as in 1940 and 1950, had to be considered metropolitan and integrated with the central city (or cities):

• To be metropolitan, a county had to:

• either contain 10,000 nonagricultural workers, or employ 10,000 nonagricultural workers, or contain at least one-tenth as many nonagricultural workers as the SMSA county with the largest city contained, or employ at least one-tenth as many nonagricultural workers as the SMSA county with the largest city employed, or contain 50+ percent of its population in minor civil divisions that had a population density of 150+/square mile and were contiguous with a central city, and,
• have a labor force that was at least 75 percent nonagricultural.

• For a county to be considered integrated with the central city:

• 15+ percent of the workers residing in the county had to work in the county/counties containing the SMSA's central city/cities, or
• 25+ percent of the workers employed in the county had to live in the county/counties containing the SMSA's central city/cities.

Like 1950 SMAs, 1970 New England SMSAs follow town and city (not county) boundaries. Furthermore, the 1970 census used a different criterion for metropolitan character in New England than the one used for the rest of the country; a town or city was considered metropolitan in New England if its population density was 100+/square mile.

Due to confidentiality requirements, in 1970, SMSAs are identified in METAREA only if they contained 250,000+ residents.

1980

The 1980 SMSA definition is essentially the same as that for 1970, although one 1980 SMSA (Nassau-Suffolk, NY) had no proper central city.

In 1980, the population threshold for identifying an SMSA by name (in METAREA) was 100,000 residents. The 1980 State sample identifies only the 180 qualifying SMSAs that do not cross state lines. The 1980 Metro sample identifies all 282 qualifying SMSAs and codes the 36 remaining SMSAs into 18 SMSA pairs, each with a combined population of 100,000+. The pairing allows all metropolitan territory to be identified without violating confidentiality requirements. The pairs that share a common code are the following:

• Bangor, ME and Lewiston-Auburn, ME
• Tioga County, NY (part of the Binghampton, NY/PA SMSA) and Elmira, NY
• Bismark, ND and Grand Forks, ND/MN
• Bloomington, IN and Owensboro, KY
• Bristol, CT and Meriden, CT
• Bryan-College Station, TX and Sherman-Dennison, TX
• Guilford County, NC (excluding Greensboro city and High Point city; the entire county is part of the Greensboro-Winston-Salem-High Point, NC SMSA) and Burlington, NC
• Casper, WY and Great Falls, MT
• Dubuque, IA and Iowa City, IA
• El Paso, TX (excluding El Paso city) and Las Cruces, NM
• Lawton, OK and Enid, OK
• Fitchburg-Leominster, MA and Pittsfield, MA
• Fort Walton Beach, FL and Panama City, FL
• La Crosse, WI and Rochester, MN
• Laredo, TX and Victoria, TX
• Topeka, KS (excluding Topeka City) and Lawrence, KS
• Saline County, AR (part of Little Rock-N. Little Rock, AR SMSA) and Pine Bluff, AR
• Midland, TX and San Angelo, TX

Some metropolitan areas are only partly identified in the 1980 State sample. See the Incompletely Identified Metropolitan Areas page for details.

1990 and 2000

METAREA designations for 1990 and 2000 samples are based on 1990 and 1999 OMB metropolitan area delineations (as were the 1990 and 2000 census tabulations). The 1990 and 1999 delineations used virtually the same standards as in 1970 and 1980 SMSAs and were therefore very similar to the SMA concept of 1950. The 1990 and 1999 MAs are further divided into:

• Free-standing Metropolitan Statistical Areas (MSAs), which are generally surrounded by non-metropolitan territory and therefore are not integrated with other metropolitan areas, and
• Primary Metropolitan Statistical Areas (PMSAs), which are the same as MSAs except that they are near, and economically/socially linked to, other PMSAs, which grouped together form larger Consolidated Metropolitan Statistical Areas (CMSAs).

Many PMSAs correspond to SMSAs or SMAs from before 1990, so for consistency across samples, METAREA codes correspond to PMSAs and not CMSAs.

As in the 1980 State sample, many metropolitan areas are only partly identified in the 1990 and 2000 samples. See the Incompletely Identified Metropolitan Areas page for details.

ACS and PRCS

In samples from the American Community Survey (ACS) and Puerto Rico Community Survey (PRCS), METAREA designations are based on 1999 OMB delineations rather than the more recent 2003 or later delineations. This is partly because the newer delineations use significantly revised standards that impair comparability with earlier delineations. Most notably, newer delineations use a revamped 5-digit code scheme distinct from the 4-digit METAREA scheme, and all new metropolitan areas are county-based, even in New England.

Another reason METAREA continues using 1999 OMB delineations is that, through 2011, the smallest geographic units identified in ACS and PRCS PUMS were 2000 PUMAs, so for each ACS and PRCS release, it has been more practical to identify METAREA codes by re-using established equivalencies between 2000 PUMAs and 1999 MAs rather than updating equivalencies for each new set of OMB delineations.

The 2012 ACS and PRCS PUMS were the first to use 2010 PUMAs and not 2000 PUMAs. Because new equivalency files were needed to associate the 2010 PUMAs with metro areas, the release of 2012 samples was an appropriate occasion to break with the 1999 OMB MA delineations. Rather than extend METAREA using new MA delineations, IPUMS instead created a new variable, MET2013, that uses 2013 OMB MSA standards with the new 5-digit code scheme. The 2022-2031 ACS/PRCS PUMS samples associate 2020 PUMAs with metro areas. Similar to before, IPUMS created a new variable, MET2023, that uses 2023 OMB MSA standards. In addition, the newer MET2013 and MET2023 variables use an alternative PUMA-to-MSA assignment strategy that yields more representative samples of metro area populations. See the overview page: IPUMS USA Variables for Metropolitan Areas for more information.

The 2003 ACS PUMS contained a metropolitan status variable that combined information about 1999 CMSAs and MSAs. Since the 2003 ACS did not sample every county in the country, many metropolitan areas in the 2003 data lack cases from one or more counties. METAREA identifies only those MSAs that were completely identifiable in the 2003 data. Data for partially identified MSAs/CMSAs and fully identified CMSAs are available in the variable MET2003.

Universe

Availability

• 2023: --
• 2022: --
• 2021: --
• 2020: --
• 2019: --
• 2018: --
• 2017: --
• 2016: --
• 2015: --
• 2014: --
• 2013: --
• 2012: --
• 2011: All samples
• 2010: ACS; ACS 3yr; ACS 5yr
• 2009: All samples
• 2008: All samples
• 2007: All samples
• 2006: All samples
• 2005: All samples
• 2004: --
• 2003: All samples
• 2002: --
• 2001: --
• 2000: 5%; 1% old; 1% unwt; 1%
• 1990: 5% state; 1% metro; 1% unwt; 3% elderly
• 1980: 5% state; 1% metro
• 1970: 1% metro fm1; 1% metro fm2
• 1960: 5%
• 1950: 1%
• 1940: All samples
• 1930: All samples
• 1920: All samples
• 1910: All samples
• 1900: All samples
• 1880: All samples
• 1870: All samples
• 1860: All samples
• 1850: All samples

• 2023: --
• 2022: --
• 2021: --
• 2020: --
• 2019: --
• 2018: --
• 2017: --
• 2016: --
• 2015: --
• 2014: --
• 2013: --
• 2012: --
• 2011: All samples
• 2010: PRCS; PRCS 3yr; PRCS 5yr
• 2009: All samples
• 2008: All samples
• 2007: All samples
• 2006: All samples
• 2005: All samples
• 2000: All samples
• 1990: All samples
• 1980: All samples
• 1970: PR 1% metro
• 1930: --
• 1920: --
• 1910: --

Flags

This variable has no flags.

Editing Procedure

There is no editing procedure available for this variable.