[Federal Register Volume 63, Number 244 (Monday, December 21, 1998)]
[Notices]
[Pages 70526-70561]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 98-33676]
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_______________________________________________________________________
Part III
Office of Management and Budget
_______________________________________________________________________
Alternative Approaches to Defining Metropolitan and Nonmetropolitan
Areas; Notice
Federal Register / Vol. 63, No. 244 / Monday, December 21, 1998 /
Notices
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OFFICE OF MANAGEMENT AND BUDGET
Alternative Approaches to Defining Metropolitan and
Nonmetropolitan Areas
AGENCY: Executive Office of the President, Office of Management and
Budget (OMB), Office of Information and Regulatory Affairs (OIRA).
ACTION: Notice of intent to review the standards currently used to
define metropolitan areas and to propose standards for defining
nonmetropolitan areas following the 2000 census.
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SUMMARY: OMB defines metropolitan areas (MAs) in the United States and
Puerto Rico for statistical purposes, following published standards.
Statistical purposes include the collection, tabulation, and
publication of data by Federal agencies for geographic areas. Decisions
related to the criteria used to define MAs are made by OMB in
consultation with members of the Metropolitan Area Standards Review
Committee (MASRC), a group representing various statistical agencies
within the Federal Government. The last revision of the MA standards
was issued in 1990 (see Appendix A). OMB currently is conducting a full
review of the MA concept and standards.
This Notice describes potential revisions to the MA standards based
on findings from the ongoing review. The Notice begins with a brief
history of the standards and a discussion of why they may need to be
revised. It then lists the findings of the review process to date,
distinguishing between points of general agreement and questions still
needing to be resolved. The Notice presents four approaches to defining
metropolitan and nonmetropolitan areas that answer in varying ways the
unresolved questions.
Issues for Comment: OMB is interested in receiving comments from
the public on (1) the suitability of the current standards, (2)
principles that should govern any proposed revisions to the standards,
(3) reactions to the four approaches outlined in this Notice, and (4)
proposals for other ways by which to define metropolitan and
nonmetropolitan areas. In particular, OMB seeks responses to the
following key questions that will determine how metropolitan and
nonmetropolitan areas will be defined in the future:
What geographic unit should be used as the ``building
block'' for defining areas for statistical purposes?
What criteria should be used to aggregate the geographic
building blocks into statistical areas?
What criteria should be used to define a set of
statistical areas of different types that together classify all the
territory of the Nation?
DATES: Comments must be received on or before February 12, 1999.
ADDRESSES: Written comments should be submitted to James D.
Fitzsimmons, Population Division, Bureau of the Census, Washington, DC
20233-8800; fax (301) 457-2644.
Electronic Data Availability and Comments: This Federal Register
Notice is available electronically from the OMB home page on the World
Wide Web: <<http://www.whitehouse.gov/WH/EOP/OMB/html/fedreg.html>>.
Federal Register Notices also are available electronically from the
U.S. Government Printing Office web site: <<http://www.access.gpo.gov/
su____docs/aces/aces140.html>>. Questions about accessing the Federal
Register online via GPO Access may be directed by telephone to (202)
512-1530 or toll free to (888) 293-6498; by fax to (202) 512-1262; or
by E-mail to <<[email protected]>>.
FOR FURTHER INFORMATION CONTACT: James D. Fitzsimmons, Chair,
Metropolitan Area Standards Review Committee, (301) 457-2419, or E-mail
<<[email protected]>>.
SUPPLEMENTARY INFORMATION:
Outline of Notice
Part I. Background
A. What Is a Metropolitan Area?
B. What Is the Purpose of Defining Metropolitan Areas?
C. How Has the Metropolitan Area Concept Evolved?
D. Why Should the Metropolitan Area Standards Be Reviewed for
Possible Revision?
Part II. Issues Posed by the Review
A. Points of General Agreement
B. Questions Remaining to Be Resolved
Part III. Form and Function in Metropolitan and Nonmetropolitan
Area Definitions
A. Functional Integration
B. Metropolitan Character
C. Central Cores
D. Geographic Building Blocks for Metropolitan and
Nonmetropolitan Areas
Part IV. Alternative Approaches to Defining Metropolitan and
Nonmetropolitan Areas
A. A Commuting-Based, County-Level Approach to Defining
Metropolitan and Nonmetropolitan Areas
B. A Commuting-Based, Census Tract-Level Approach to Defining
Metropolitan and Nonmetropolitan Areas
C. A Directional Commuting, Census Tract-Level Approach to
Defining Metropolitan and Nonmetropolitan Areas
D. A Comparative Density, County-Level Approach to Defining
Statistical Areas
Part V. Additional Issues for Consideration
A. Accounting for Residual Areas
B. Development of Multiple Sets of Statistical Areas
C. Settlement Types Within Metropolitan and Nonmetropolitan
Areas
Part VI. Sources Cited
Part VII. Frequently Used Terms
Appendices
A. Revised Standards for Defining Metropolitan Areas in the
1990s
B. OMB Memorandum M-94-22, ``Use of Metropolitan Area
Definitions''
C. Summary of the Conference on New Approaches to Defining
Metropolitan and Nonmetropolitan Areas
Part I. Background
A. What Is a Metropolitan Area?
Currently, an MA consists of a core area containing a large
population nucleus, together with adjacent communities having a high
degree of social and economic integration with that core. MAs generally
include a city or a Census Bureau-defined urbanized area (UA) with
50,000 or more inhabitants. The county or counties that contain the
large city or the UA are the central counties of the MA. Additional
outlying counties are included in the MA if the counties meet specified
requirements of commuting to or from the central counties and other
selected requirements of metropolitan character. The term
``metropolitan area'' is a collective term that refers to metropolitan
statistical areas (MSAs), consolidated metropolitan statistical areas
(CMSAs), and primary metropolitan statistical areas (PMSAs). The
current (1990) standards for defining MAs are included as Appendix A of
this Notice.
B. What Is the Purpose of Defining Metropolitan Areas?
MAs are a Federal statistical standard designed solely for the
preparation, presentation, and comparison of data. Before the MA
concept was introduced in 1949 with Standard Metropolitan Areas (SMAs),
inconsistencies between statistical area boundaries and units made
comparisons of data from Federal agencies difficult. Thus, MAs are
defined according to specific, quantitative criteria (standards) to
help government agencies, researchers, and others achieve uniform use
and comparability of data on a national scale.
OMB recognizes that some Federal and state agencies are required by
statute to use MAs for allocating program funds, setting program
standards, and implementing other aspects of their programs. In
defining MAs, however, OMB does not take into account or attempt to
anticipate any of these nonstatistical uses that may be
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made of MAs or their associated data. Agencies that elect to use MAs
for such nonstatistical purposes are advised that the standards are
designed for statistical purposes only and that any changes to the
standards may affect the implementation of programs. This policy was
documented in OMB memorandum M-94-22, dated May 5, 1994, entitled ``Use
of Metropolitan Area Definitions'' (see Appendix B).
C. How Has the Metropolitan Area Concept Evolved?
As early as the first years of the twentieth century, the Federal
Government recognized the need to identify large cities and their
surrounding areas as single geographic entities and to provide data at
that scale for social and economic analysis. Before the adoption of the
MA concept in the late 1940s, several other kinds of related geographic
areas were defined. These areas were based on different criteria and
used by Federal agencies for data reporting purposes. Among these areas
were the following:
Industrial Districts. Perhaps the first extensive attempt by the
Federal Government to define areas based on a metropolitan concept was
the identification of industrial districts for the 1905 Census of
Manufactures. The Census Bureau published manufacturing and population
data for 13 industrial districts composed of minor civil divisions
(MCDs).
Metropolitan Districts. When adopted by the Census Bureau in 1910,
each metropolitan district generally comprised a central city of at
least 200,000 persons and all adjacent MCDs with population densities
of at least 150 persons per square mile. Beginning in 1930,
metropolitan districts were defined for all cities of at least 50,000
persons, with the additional requirement that each metropolitan
district have a population of at least 100,000. Metropolitan districts
were defined in terms of population density; measures of functional
integration (such as commuting) were not used.
Industrial Areas. Industrial areas were introduced by the Census
Bureau in the late-1920s for the Census of Manufactures to provide a
coherent, integrated unit for reporting data related to industrial
activity. Each industrial area comprised a county containing an
important manufacturing city and adjacent counties with significant
concentrations of manufacturing industries. Each of these areas usually
employed at least 40,000 factory wage earners. In 1931, there were 33
recognized industrial areas.
Labor Market Areas. Before 1950, labor market areas (LMAs) were
defined by the Bureau of Employment Security and consisted of counties
and MCDs. Since 1950, the Bureau of Labor Statistics (BLS) has been
responsible for defining LMAs. Current LMA definitions use MAs as
starting points and consist of aggregations of counties (see below).
Lack of geographic comparability limited the use of data reported
for these and other areas. In the mid-1940s, initial efforts to
reconcile metropolitan districts and industrial areas failed, in part
because of tensions between two groups, demographic data providers and
economic data providers. The former wanted to continue using sub-county
geographic building blocks to achieve greater precision and to maintain
historical comparability with metropolitan districts. The latter had
difficulty identifying precise locations of establishments below the
county level and also had concerns about the availability and
confidentiality of sub-county data.
The Interagency Committee on Standard Metropolitan Areas decided in
March 1948 that counties would form the building blocks for SMAs. The
Committee cited the greater availability of data for counties and
concluded that use of a unit other than the county would restrict the
amount of information available for SMAs and, consequently, would
reduce the usefulness of the concept.
SMAs were first used for reporting data from the 1947 Census of
Manufactures. The conceptual basis for the SMA was a community of
nonagricultural workers who resided in and around a large city and were
socially and economically linked with the central city as measured by
commuting flows and telephone calls.
Changes to the standards since their adoption for the 1950
decennial census are detailed in Table 1. Few significant changes were
made through the 1960s; those that were made affected the designation
of central cities forming the cores of MAs. The standards became more
complex in the 1970s and 1980s, in part to recognize the increasing
variation in patterns of urban settlement. Requirements for central
cities were adjusted for the 1980s, with the result that more cities
were designated as central. Additional changes at that time meant MAs
included fewer outlying counties, which needed to satisfy commuting
requirements as well as a number of other criteria, including:
population growth rate, percent urban population, percent of population
living inside a UA, and overall population density. The 1990 (current)
standards differ only modestly from those of the previous decade.
Since their adoption in the late 1940s, the MA standards have
acknowledged that within states in New England, cities and towns are
administratively more important than counties, and that a wide variety
of data are compiled for these areas. For these reasons, cities and
towns have been used as the building blocks of MAs in New England. The
nonagricultural worker requirement that was present in the earlier
standards was not applied in New England. Also, population density
requirements differed between New England and elsewhere.
The standards for New England MAs remain different from the
standards for the rest of the country. New England County Metropolitan
Areas'county-based alternatives to the city-and town-based MAs of that
region--were introduced in 1975 to facilitate comparisons between areas
in New England and elsewhere.
In addition to MAs, other statistical area classifications
currently are in use. These include:
Labor Market Areas. BLS currently defines LMAs, which are used for
a variety of purposes, including reporting local area unemployment
statistics. LMAs follow county boundaries except in New England, where
towns and cities are the geographic building blocks. BLS defines major
LMAs based on MSAs and PMSAs as defined by OMB. Outside of MAs, BLS
defines small LMAs by aggregating counties (or towns) on the basis of
commuting. LMAs are non-overlapping and geographically exhaustive.
Economic Areas. The Bureau of Economic Analysis (BEA) defines
economic areas (EAs) for reporting geographically detailed economic
data and for regional economic analysis. In delineating EAs, BEA
identifies economic nodes. These nodes consist of 310 MSAs and PMSAs
(NECMAs in New England) plus 38 nonmetropolitan counties. Each county
not included in these nodes is analyzed to determine the node with
which it is most closely associated. Measures such as commuting
patterns and regional newspaper circulation are used to aggregate
counties into ``component economic areas,'' which are then aggregated
to form the final EAs. EAs are county-based, nonoverlapping, and
geographically exhaustive.
In sum, the MA concept is part of an historical lineage of
statistical geographic areas and is one of several
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current areas used by Federal agencies for reporting data.
D. Why Should the Metropolitan Area Standards Be Reviewed for Possible
Revision?
The MA standards, like other statistical standards, require review
to ensure their continued usefulness. Previous reviews and revisions of
the MA standards were completed in 1958, 1971, 1975, 1980, and 1990.
Comments received in recent years indicate there are four widely
held opinions regarding the current MA standards that argue for their
revision:
Many users believe the current standards are overly
complex and burdened with ad hoc criteria. Simplifying the standards
would improve the chances that the system and its associated data would
be understood.
The MA concept has not changed significantly since 1950,
yet population distribution and activity patterns in the United States
have changed as a result of changes in transportation and other
technologies, home/workplace relationships, and patterns of retail and
other commercial location. Revised MA standards may better represent
increasingly decentralized settlement and activity patterns.
Computer-related advances in data collection, storage, and
analysis, especially in technologies related to data geocoding (data
linked to its geographic location of occurrence), make it feasible to
consider a sub-county unit as the basic geographic building block for
constructing statistical areas to represent settlement.
MAs do not exhaustively classify the territory of the
United States. As a result, social and economic linkages within the
residual, nonmetropolitan territory are not taken into account
appropriately in statistical data series.
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Part II. Issues Posed by the Review
The MA standards are reviewed for possible revisions before each
decennial census. The current review began early in this decade and
already has included commissioned research, publications,
presentations, discussions, and a conference (see Appendix C for notes
from the 1995 ``Conference on New Approaches to Defining Metropolitan
and Nonmetropolitan Areas''). This review process has elicited the
views of Federal Government data providers, data users in the private
and academic sectors, and other analysts who use MA data and
definitions. Results to date include both points of general agreement
and questions remaining to be resolved.
A. Points of General Agreement
There seems to be general agreement on the following:
The Federal Government should continue to define standard
statistical areas at the metropolitan level.
Familiar components of settlement, such as those
represented by today's MA definitions, should be in evidence in a new
system.
Revised standards should broaden territorial coverage by
including and officially recognizing nonmetropolitan components of the
settlement system.
These statistical areas should be defined according to
simplified standards that are applied consistently in all parts of the
country using the same geographic building blocks.
If the revised standards define metropolitan and
nonmetropolitan areas using sub-county building blocks, an associated,
alternative set of county-based areas also is desired.
B. Questions Remaining to Be Resolved
1. What criteria should be used to define areas that exhaust the
territory of the Nation?
One criticism of the current MA standards is that they do not
account for all of the territory of the United States. Although
tremendous variation in settlement patterns exists throughout the
country, the current system defines individual MAs and leaves all
territory outside MAs simply as ``nonmetropolitan.'' It has been
suggested that all parts of the U.S. territory, from the most to the
least populated, should be assigned to a statistical area at the
metropolitan or nonmetropolitan level. One approach to account for more
of the country's territory would define statistical areas around cores
of some minimum size that contain less than the 50,000 population
minimum required by current MAs. Reducing the required core population
threshold for statistical areas, however, probably still would leave
some residual territory, the amount dependent on the core size
requirement.
Another approach would be to classify areas based on a measure of
settlement form such as population density. This approach would account
for all of the territory of the country, although some of the resulting
statistical areas probably would be small in geographic extent,
population size, or both.
A related issue is the classification of types of locales, such as
inner city, suburban, exurban, and rural, and whether such types should
be identified within metropolitan and nonmetropolitan areas. The
definitions of MAs in the past have not included such categories.
2. What geographic unit should be used as the building block for
defining statistical areas?
MAs currently consist of entire counties, except in New England
where towns and cities form the building blocks. Problems with using
counties in this capacity have been apparent since the earliest
discussions of MAs, as revealed in this 1946 comment on the relative
merits of the MCD-based metropolitan district program:
* * * [T]he metropolitan district, based on small subdivisions of a
county, comes much closer to representing the central concept of a
metropolis and its satellite territory than does the metropolitan
county or group of counties. The metropolitan county arose as a mere
approximation to the metropolitan district, made necessary by the fact
that intercensus population data were compiled on a county rather than
on a minor civil division basis. The use of smaller territorial units
than metropolitan counties * * * leads to a much more precise analysis
of labor and housing markets (Bureau of the Census 1946).
These observations are still pertinent today. Wide regional
variation in county size presents a problem when comparing data for
different MAs. Further, the large size of some counties can mask
smaller, densely populated clusters of settlement, so that patterns of
social and economic linkages within counties are difficult to
recognize. The use of smaller geographic building blocks, such as
county subdivisions or census tracts, might help alleviate these
problems.
Although there were critical comments, a key advantage to using
counties as the geographic building block also was apparent in the
1940s: a wide range of data is available for counties, with the result
that areas composed of counties also have considerable data available
for them. (The range of Federal Government data available at the county
level that also is, or could be, available for smaller areas is under
review.) Counties also are familiar to data users, and their relatively
small number may be seen as an advantage. These issues are taken up in
more detail in Part III.D.
3. What criteria should be used to aggregate the geographic units into
statistical areas?
The current MA system is based on the observation that large urban
centers have both form and function. The form, or structural
component--what we see on the landscape--is measured using such
variables as population size and density. Settlement form largely
determines the identification of central cities and central counties.
The functional component--interactions of people and activities among
places as measured by daily commuting flows--is key to the
identification of qualified outlying counties. Substantial agreement
exists that population density (or possibly housing unit density) and
daily commuting continue to be the best means for defining areas
consistently nationwide. At the same time, however, many observers
concur that both the structural and functional components of cities and
their surroundings have changed significantly since MAs were first
defined. These components also have grown increasingly complex and
difficult to measure. Part IV presents a classification based solely on
measures of form (see Part IV.D), as well as other classifications (see
Parts IV.A, B, and C) based on a combination of measures of form (to
identify central cores) and measures of function (to identify outlying
areas integrated with the core).
4. Should the definition process follow strictly statistical rules, or
should it take into account local opinion?
The current standards take local opinion into account in specified
circumstances. Application of strictly statistical rules for definition
purposes would have the advantage of minimizing ambiguity and making
definition of areas less time-consuming. Consideration of local
opinion, however, can provide room for accommodating some issues of
local significance without impairing the integrity of the system.
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5. What should be the frequency of updating?
In the past, many observers have argued for minimizing changes in
area definitions during the course of a decade to ensure that data
bases can be maintained consistently and economically. The counter-
argument is that definitions should be updated to reflect changed
conditions as rapidly as the data permit. The frequency of updating
depends in part on decisions concerning basic geographic units,
criteria for aggregation, and, ultimately, data availability. Recent
practice has been to review areas annually on the basis of Census
Bureau population estimates and special censuses.
Part III. Form and Function in Metropolitan and Nonmetropolitan
Area Definitions
Metropolitan and nonmetropolitan areas have characteristics that
are structural, relating to population settlement form (population
density, for instance, is a structural measure), and functional,
reflecting geographic patterns of social and economic linkages that
contribute to the development of an entire area (examples include daily
commuting patterns and shopping trips). If a metropolitan and
nonmetropolitan classification is purely structural, such as would be
the case with areas based solely on population density (and as was the
case with metropolitan districts before 1950), then only the degree of
settlement is considered. Settlement form sometimes corresponds to
patterns of activity and can serve as a surrogate for functional
elements. If a system is purely functional and defined solely by
measuring activity, then there is no clear depiction of the urban
center from which influences arise and around which activity takes
place. Current MAs make use of both structural and functional measures.
This portion of the Notice addresses the topics of functional
integration, metropolitan character (structural characteristics),
central cores, and geographic units used to define metropolitan and
nonmetropolitan areas. Throughout this discussion, the phrase
``metropolitan and nonmetropolitan areas'' means those areas defined
around urban centers of varying size and complexity. ``Metropolitan''
refers to those areas defined around larger cores (current MAs have
cores with at least 50,000 population); ``nonmetropolitan'' refers to
areas defined around smaller cores. These terminology conventions are
for the immediate purposes of this discussion.
A. Functional Integration
1. Introduction
MAs have represented areas of urban influence extending beyond city
limits. The concept of the MA--a core area containing a large
population nucleus, together with adjacent areas that have substantial
measurable interactions with that core--relies heavily on the notion of
functional integration in determining geographic extent. This section
discusses metropolitan and nonmetropolitan area functional integration,
identifying commuting as the most appropriate indicator of functional
integration.
2. Increasing Complexity of Commuting Patterns
The functional measure used in the MA standards has been the daily
journey to work. Commuting identifies the extent of each MA in an
equitable and uncomplicated way. By establishing place-to-place links
between workers' homes and places of employment, commuting has provided
a measure of the economic interactions within an area. MAs are units
with distinctive identities based, in part, on where people live and
where they go to work.
Recently, however, some scholars have suggested that as the United
States becomes more interdependent, both internally and with the rest
of the world, the concept of metropolitan functional integration needs
to be examined more closely (Berry 1995). In addition, the increasing
popularity of working at home raises questions about the relevance of
commuting in defining metropolitan and nonmetropolitan areas.
Researchers (Fisher and Mitchelson 1981, Lewis 1983, Gordon and
Richardson 1996, Dear and Flusty 1998) have commented on the growing
complexity of metropolitan form and commuting patterns. Harvey (1989)
and Fishman (1990) have noted changes in urban form that reflect larger
economic forces. These changes call into question the dominance of a
large population center over adjacent communities that have high levels
of social and economic interactions with the center. Others, like
Pressman (1985) and Castells (1989), have identified a new, broader
functional integration, citing a variety of technological innovations,
including: (1) the expansion of cellular phone and Internet use; (2)
the global supremacy of American entertainment, news, and advertising;
(3) the market swings driven by political events in distant countries;
(4) the migration of factory out-sourcing and back-office operations to
low-wage countries; and (5) the speed and flexibility of global finance
and ability to move large sums of money around the world
instantaneously. All of these developments suggest a change whereby
individual places and areas become less important than the network
structure itself, and small places become single nodes in a complex
system of social and economic linkages created and organized under
constantly shifting economic and political circumstances. These
innovations point to the growing interdependence of places in general
and some blurring of individual place identities.
It is equally clear, however, that the Nation remains the sum of
many economic and social parts. Local and regional economies and labor
markets continue to show different specialities and levels of
performance. Local and regional character still exists, built in part
upon identification of place of residence or work and awareness of the
locality's history and geography.
The challenge in defining metropolitan and nonmetropolitan areas is
to select appropriate functions or activities that capture economic and
social integration within areas and the differences between areas.
Before reconsidering commuting as a measure of functional integration,
the following section discusses alternative measures of spatial
interaction.
3. Alternative Measures
The Internet provides the newest major medium for
information flows across the United States. The aspatial nature of the
Internet, however, poses difficulties for measuring functional
integration, which assumes the ability to identify the origins and
destinations of flows. The origin of each Internet session--the
location of the user--generally is identifiable, but the destination is
unclear: is it the location of the service provider, the location of
the server on which a web page resides, or the physical location of the
owner of the web page? Although Internet use generally involves a
telephone call to a specific provider location, this is only to gain
access to the wider web; the distance between the user and the location
of the owner of the accessed web page is unimportant. Because the link
between a user and a web page recedes into the background, such
linkages defy identification as measures of functional integration
between communities.
Telephone traffic patterns were used in early MA
definitions until commuting data became more widely
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available and standardized. Issues concerning telephone service
coverage largely have disappeared in recent decades.
Cellular telephone systems provide a measure of the
functional extent of metropolitan and some nonmetropolitan areas and
highlight the role played by highway corridors. Coverage is uneven,
however, due to competition between companies and the spatial
segregation of different companies' customers. Standardizing the
rapidly changing information about users and coverage areas is
difficult.
Media markets, or penetration patterns, offer an image of
regions to marketers and advertisers, but many of the data are
proprietary and exhibit uneven coverage. The advent of the Internet,
national editions of newspapers, and cable and satellite television
blurs the traditionally local flavor of media markets.
Consumer spending could, in principle, provide a view of
the functional extent of regional and metropolitan areas. Consumer
expenditure surveys, however, do not provide much data for individual
metropolitan and nonmetropolitan areas because of limited sample sizes.
In general, these alternative measures of functional integration
are not as useful as commuting patterns because they: (1) sometimes
depend on data that are not collected by Federal agencies and that may
be subject to errors of unknown kind and magnitude; (2) sometimes are
not generally accessible by the public (i.e., the measures are
proprietary, sometimes copyrighted or for sale); (3) are without
observations that are evenly distributed across the U.S. territory; and
(4) are not measurable in terms of specific, common geographic units.
4. Continued Usefulness of Commuting Patterns as a Measure
Notwithstanding criticism of continued reliance on information
about the daily journey to work, it remains the most reliable and
broadly available measure of functional integration for two principle
reasons:
Commuting to work is still a significant activity for the
vast majority of workers. Recent years have seen a rise in alternative
work-residence arrangements. Shortened or irregular work weeks,
flextime, full-and part-time work at home, and telecommuting some or
all of the time are gaining in importance. The Census Bureau reported a
55 percent increase in those working at home between 1980 and 1990,
from 2.2 million to 3.4 million workers. Still, those working at home
represented only three percent of all workers in 1990. Ninety-seven
percent of workers still commute to work and have separate location
spheres for place-of-work and place-of-residence. This long-term
pattern reflects the nature of many jobs, for instance, where service
provision is location-specific or product manufacture occurs in a fixed
location.
The spatial patterns of commuting are more complex today
than in previous decades, but no less important. The spatial structure
of the urban environment is less consistently monocentric than was the
case in the early part of the twentieth century. Given the diffusion of
persons and jobs away from the core, commuting patterns are less likely
to resemble a hub-and-spoke model than a polycentric structure of
multiple employment nodes serving a region's needs. The increased
complexity of these patterns, however, has not meant a decrease in
their importance.
Over time, commuting patterns in many areas have become more
complicated to delineate. Jobs have followed people out of the central
city (and the central county), but the traditional urban core, with an
employment-intensive central business district, still exists amidst
high job growth in suburban areas. Commuting often is multidirectional,
with no single dominant flow. The net commuting flow between any two
areas may be quite low, while the gross flows may be substantial.
Work is still a dominant organizing activity in most people's
lives. While urban settlement form has changed, the basic movement of
workers traveling to a different location from where they live
continues. The geographic extent of metropolitan and nonmetropolitan
areas ``depends upon the commuting range, itself historically
determined by social and technological conditions'' (Harvey 1989). The
journey-to-work activity is nearly universal, even as the geographic
nature of commuting has changed in recent decades. The challenge is to
model and measure the current nature of commuting patterns to delineate
metropolitan and nonmetropolitan areas.
B. Metropolitan Character
1. Introduction
Since SMAs were first defined in 1949, counties have needed to
exhibit, in addition to integration (as measured by commuting), other
attributes referred to collectively as ``metropolitan character'' to
qualify as outlying. As the March 1958 MA standards noted, ``The
criteria of metropolitan character relate primarily to the attributes
of the county as a place of work or as a home for a concentration of
non-agricultural workers.'' In practice, this has meant an emphasis
primarily on population density as one aspect of what makes an outlying
county ``metropolitan.'' This section addresses the suitability of
including measures of metropolitan character--focusing on population
density--in standards for defining areas in the next decade.
2. Density and Other Measures of Metropolitan Character
The initial inclusion of population density in the MA criteria
reflected some common, contemporary assumptions about U.S. settlement
patterns in 1949:
An easily understood built environment: cities were
densely settled centers of population and economic activity set against
a backdrop of sparsely settled territory.
Population density as a proxy for distance from the
central business district: population density declined as distance from
an urban center increased.
Relationship of distance from the urban center and
population density with social, economic, and cultural attributes of
the population: urban and rural communities, for example, were
understood to be different in characteristics ranging from industry and
occupation to educational attainment and family size.
Most important, metropolitan form and function were
invariably linked; that is, metropolitan territory that was linked
socially and economically necessarily had visible landscape
characteristics and was typified by high relative population density.
Five decades of urban, suburban, and exurban growth may have
subsequently altered the meaning of ``metropolitan character.'' Since
1949, additional measures of metropolitan character--rapid population
growth, percentage of urban population, and presence of UA population--
have been added to the standards to measure other important attributes.
Up-to-date MA standards should continue to reflect the evolving nature
of settlement patterns and demographic characteristics in the United
States. Change in this aspect of the standards is not new: for example,
the 1980 MA standards eliminated a metropolitan character criterion
pertaining to non-agricultural workers; the steep drop in agricultural
employment nationwide had made such a criterion irrelevant.
Enormous variation in population density still exists in the United
States, from the densely populated sections of
[[Page 70535]]
some older cities to the sparsely settled areas of the interior West.
An increasing share of the Nation's population, however, resides in a
built environment that is of neither extremely high nor extremely low
density. The percentage of the population living in rural areas has
declined from approximately 29 to 24 since 1950, and the percentage of
the population living in central cities of metropolitan areas has
declined from 33 to 31 despite increases in the number of central
cities. In contrast, the percentage of the Nation's population living
within MAs but outside central cities has doubled, from 23 to 46. The
Nation's population steadily has been moving away from landscapes of
population density extremes, both high and low.
Population growth in nonmetropolitan America is occurring
predominantly in the smaller cities and towns, particularly in areas
adjacent to or near MAs. One consequence of this growth of intermediate
density areas is a blurring of many of the sharp differences in
population density that once existed between urban and rural areas or
between metropolitan and nonmetropolitan areas.
Improvements in communications technology and transportation
infrastructure also have blunted the differences between high-density
and low-density areas. In the past, telephones, well-paved roads, and
railroads connected rural areas with their urban markets, but the
friction of distance was much higher than today; ideas and cultural
attitudes traveled according to weekly, monthly, and seasonal rhythms.
In 1949, settlement form still was intertwined closely with
function. Areas having high population densities also were those that
were linked closely with urban centers. The 1949 SMA standards were
written before the construction of interstate highways and could not
have anticipated the changes in commuting and settlement patterns
brought about by high-speed highways. These highways improved access to
rural, low density areas that previously were beyond the scope of most
urban influences and daily commuting. With less expensive long distance
telephone service, interstate highways providing quick and easy access
to cities and towns, satellite uplinks and commercial television
broadcasting nationally, and the Internet, population density is a less
significant variable. Population density no longer correlates with
differences in industry, occupation, family structure, and other
variables to the extent that it did 30 to 50 years ago. It is more
difficult to argue that sparsely settled areas must meet different
criteria of integration with central cores than areas with higher
population densities. Consequently, population density has become less
relevant as a direct measure of ways in which communities are linked
socially and economically.
C. Central Cores
1. Introduction
Cores of metropolitan regions continue to be vital centers of
activity even as the decentralization of many economic and social
functions continues. Central business districts contain significant
clusters of government facilities; corporate headquarters; finance,
insurance, and real estate firms; entertainment complexes; and services
that cater to these facilities. Many establishments located in suburban
areas provide services to central city clients and depend heavily upon
them. While the core has changed over time, it remains a key component
of metropolitan regions.
The MA standards always have explicitly incorporated central cores
as one of the major components in the definition of individual areas
(see Table 1). Two kinds of changes in central core requirements are
under consideration--changing minimum population requirements and
changing criteria for the definition of cores.
2. Changing Minimum Population Requirements
One option under review would raise the minimum population level
for the definition of MA cores from 50,000 to 100,000. Doubling the
current threshold would take into account the significant increase
(over 100 percent) in the Nation's population since 1930 (the first
year in which the 50,000 person minimum was used in identifying cores
of metropolitan districts) and the consequent relative decrease in the
significance of a core of 50,000 population. The new threshold would
facilitate greater comparability with another major statistical data
set, the public use microdata samples (PUMS) from the decennial census,
which are used extensively by researchers examining metropolitan and
nonmetropolitan issues (Fotheringham and Pellegrini 1996).
Along with an increase in minimum population size for MA cores, the
classification would be expanded to address smaller cores as well. By
including provision for one or two additional sets of areas, the new
standards could better account for gradations in population focused
around urban centers of varying size throughout the United States. If
MA cores were to have a minimum of 100,000 persons, then other sets of
areas could be defined using cores of (1) at least 10,000 persons and
less than 50,000 persons, and (2) at least 50,000 persons and less than
100,000 persons. Identifying coherent nonmetropolitan areas based
around smaller population centers provides a potential improvement for
analysts and researchers who are dissatisfied with a system that leaves
nonmetropolitan areas largely undifferentiated.
3. New Criteria for Defining Cores
In addition to using places and Census Bureau-defined UAs based on
population and population density to define metropolitan or
nonmetropolitan cores, at least four other criteria could be used. One
alternative would be to use housing unit density as the primary
defining characteristic. A second alternative would be to combine two
characteristics, population and employment. This would involve
calculating ratios that compare the number of individuals employed in a
geographic area to the number of residents in the same area. The
explicit use of such an employment measurement in the definition of a
core would be a logical extension of the use of another employment-
related statistic, commuting patterns, to define those areas that are
integrated with the core. A third option would be to rely solely on
employment as the defining characteristic by delineating cores on the
basis of employment density, defined as the number of jobs per unit of
area.
A fourth alternative would use commuting data directly to identify
cores as those areas that exhibit strong evidence of multi-directional
commuting. In this approach, multi-directional commuting indicates
interdependence within the core of an urban area and could be used to
define inner city and inner suburban territory. Outlying territory
integrated with a particular core would contain mostly uni-directional
commuting flows toward that core and could be used to define outer
suburban territory.
These different approaches to defining cores of metropolitan and
nonmetropolitan areas reflect changes in settlement and commuting
trends, as well as technological improvements in geographic analysis;
yet, they remain consistent with the tradition of identifying the
Nation's large urban centers.
[[Page 70536]]
D. Geographic Building Blocks for Metropolitan Areas and
Nonmetropolitan Areas
1. Introduction
This section addresses the relative merits of various potential
geographic building blocks. The geographic unit used to define
metropolitan and nonmetropolitan areas is important to data providers
and users due to: (1) its effect on the geographic extent of a
statistical area; (2) its meaningfulness in describing economic and
social integration between communities; and (3) the ability of Federal
agencies to provide data for comparable statistical areas and their
components. The choice of whether to use counties or county
subdivisions as building blocks for MAs was a central issue in the
1940s during development of the MA program; resolution of the issue at
that time favored greater availability of data over greater geographic
precision in defining social and economic linkages.
The concerns raised in the 1940s also are central issues in this
review. Counties are familiar geographic units offering the advantage
of a wider range of statistically reliable economic and demographic
data. Because of their geographic extent, however, counties can include
territory and population not functionally integrated with a specific
core. Sub-county entities offer greater resolution when analyzing
economic and demographic patterns, and increased precision when
defining statistical areas. These smaller units are at a disadvantage,
however, because fewer economic and demographic data series are
available for sub-county entities than for counties, and there would be
less comparability of units defined on this basis with previously
defined metropolitan and nonmetropolitan areas.
2. Characteristics of the Metropolitan and Nonmetropolitan Area
Building Blocks
The geographic entity used as a building block should have the
following characteristics:
Consistency. The geographic building block should be
delineated in a consistent fashion across the Nation. The degree to
which this is the case both within a state and from one state to
another affects the ability to make meaningful comparisons of
demographic and economic data.
Data Availability and Utility. Data for a geographic
building block should be available from a wide variety of sources and
should facilitate the linkage of various data sets.
Stability of Boundaries. The ability of the geographic
building block to be flexible in portraying demographic and economic
change over time in areas is important when defining and analyzing
social and economic linkages between communities.
Familiarity. The geographic unit used to define
metropolitan and nonmetropolitan areas should be meaningful and
recognizable to a wide range of data users.
Table 2 details the advantages and disadvantages of using each of
five geographic units (counties, county subdivisions, census tracts,
ZIP Codes, and grid cells) as building blocks in relation to the
characteristics outlined above. The following paragraphs summarize the
significant issues from Table 2 and discuss related issues of
confidentiality and data reliability.
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Counties. Except in New England, counties currently are used to
define MAs. Counties are well-known, with boundaries that rarely
change, and they are useful for analyzing data over time. Data
currently are available for counties from a wide variety of Federal,
state, and local agencies and less frequently are limited by disclosure
and statistical reliability issues than sub-county units. Counties,
however, are established according to state laws and have as their
primary purpose the administration of local government and provision of
programs and services. As a result, there is little consistency in
population size and land area among counties throughout the United
States. The large size of counties in the West often poses challenges
to measuring and analyzing localized shifts in population.
County Subdivisions. County subdivisions currently are used to
define MAs in New England, and before 1950 were used to define
metropolitan districts. County subdivisions include MCDs, such as towns
and townships, and census county divisions (CCDs). MCDs are
governmental or administrative entities defined according to state
laws. CCDs are defined for statistical purposes by local officials
using nationally consistent criteria and guidelines issued by the
Census Bureau. As with counties, the population sizes and land areas of
county subdivisions vary both within state and from one state to
another. Governmentally functioning MCDs in the Northeast as well as
most CCDs generally have stable boundaries; elsewhere, MCD boundaries
may change because of annexations or mergers. Redistricting of
administrative MCDs, particularly in Virginia and North Carolina, can
result in substantial changes each decade. Accounting for these changes
could require significant retabulations of data for metropolitan and
nonmetropolitan areas, potentially compromising comparability of data
over time. The volume of economic and demographic data collected and
published for county subdivisions varies, with greater amounts
available for MCDs with functioning governments and lesser amounts for
MCDs without functioning governments and CCDs. Despite variations in
population size and instability of boundaries for some MCDs and CCDs,
county subdivisions could provide a compromise between the
disadvantages posed by the geographic extent of counties and the more
limited availability of economic data for some other sub-county
geographic units.
Census Tracts. Local officials define census tracts using
nationally consistent criteria and guidelines established by the Census
Bureau. Census tracts have a consistent population size range (between
1,500 and 8,000, with an optimum of 4,000) to ensure statistical
reliability of data. Census tracts vary in size and shape and tend to
reflect contemporary local settlement patterns. Census tracts are meant
to facilitate analysis of time-series data at a sub-county level, and
are generally stable. Because they are defined in terms of population
count, however, census tracts are capable of portraying change over
time by changing boundaries. If a tract increases in population, it can
be split to form new census tracts that aggregate to the original
boundaries. For the 1990 decennial census, approximately 30 percent of
all census tracts had boundary changes. Although demographic data
generally are available for census tracts, a key disadvantage is the
dearth of economic data available at the census tract level. Data for
census tracts, however, are becoming increasingly important for
understanding and analyzing patterns of home ownership and economic
development, as well as the general social and physical environment
within metropolitan and nonmetropolitan areas.
ZIP Codes. The U.S. Postal Service (USPS) establishes ZIP Codes to
facilitate efficient mail delivery. ZIP Codes are linear rather than
areal (i.e., they are routes that mail carriers walk or drive) and as a
result do not have discrete boundaries. In some instances, when the
volume of mail is particularly high, a ZIP Code may refer to a specific
building, a floor within a building, or even a specific office. Because
ZIP Codes exist for operational purposes, they can be taken out of use
when the population of an area declines or when the USPS consolidates
post offices. The USPS, however, sometimes reuses such ZIP Codes in a
different location, thus creating a false sense of comparability if
used as geographic areas. Despite their shortcomings as geographic
units, ZIP Code use is, nevertheless, ubiquitous for collecting and
reporting information on demographic and economic characteristics as
well as for carrying out surveys and market analysis studies that
report on consumption patterns and lifestyle characteristics.
Grid Cells. Grid cells are not in use currently by Federal
statistical agencies. If established, however, they could provide ideal
units for analyzing population change within stable boundaries. If
relatively small in geographic extent, they also could be useful in
measuring population change across space. Grid cells would be defined
consistently nationwide and all would encompass a similar amount of
territory. Although grid cells may offer advantages from delineation,
measurement, and analysis standpoints, their lack of familiarity and
relationship with geographic areas that are more real and familiar to
people offer significant disadvantages to their use. In addition,
adoption of grid cells would require data providers to convert from use
of current geographic entities. Selection of grid cell size would
require careful consideration of confidentiality and statistical
reliability concerns.
3. Quality and Availability of Data
In general, the quality of data for particular areas is related to
the allocation of questionnaire responses to specific geographic
entities and to the statistical reliability of the data derived from a
sample. The geographic precision of data is only as good as the
completeness of location information provided in the response, and the
quality of geographic codes assigned to it. This limitation affects the
ability to report data at varying levels of geography.
Respondent confidentiality also must be considered when determining
which geographic area to use as a building block, particularly if data
are to be reported for components of metropolitan and nonmetropolitan
areas. In general, the larger the number of observations (persons,
households, establishments within a specific industry) within a
geographic entity, the greater the ability to protect respondent
confidentiality.
Not all Federal data can be provided for every level of geography,
and the frequency with which Federal data are available also can vary
by level of geography. Sample size limitations for some demographic
survey data make survey results reliable only at higher levels of
geography. The diffuse nature of modern manufacturing processes renders
some economic data, for instance the amount of value added to a product
at each step in the manufacturing process, difficult to portray at
levels of geography below the state or Nation. Data that are available
only from the decennial census place limitations on the frequency of
updating some statistical areas. The uncertain availability of
intercensal population estimates for census tracts, and the likelihood
that tract-level commuting data from the American Community Survey will
not be available for all census tracts until 2008, also will affect the
ability to update metropolitan and nonmetropolitan areas.
[[Page 70540]]
4. Summary
The choice of a building block should focus on achieving the most
precise geographic delineation of metropolitan and nonmetropolitan
areas possible, given the constraints of data availability. Collecting,
processing, and tabulating data at sub-county levels of geography are
important technical issues that must be resolved within individual
Federal statistical agencies if a sub-county geographic unit is to be
used to define metropolitan and nonmetropolitan areas.
Counties and census tracts offer the greatest promise as potential
building blocks for metropolitan and nonmetropolitan areas based on
current availability and reliability of statistical data, general
stability of boundaries over time, consistency of definitions, and
familiarity among data users. Counties and census tracts, therefore,
are used in the examples of alternative methods for defining
metropolitan and nonmetropolitan areas that follow in Part IV.
Part IV. Alternative Approaches to Defining Metropolitan and
Nonmetropolitan Areas
This part presents four alternative approaches to defining
metropolitan and nonmetropolitan areas: (1) a commuting-based, county-
level approach; (2) a commuting-based, census tract-level approach; (3)
a directional commuting, census tract-level approach; and (4) a
comparative population density, county-level approach. Table 3
summarizes how each approach addresses issues raised in Parts I and II
of this Notice.
All four of these approaches differ from the current (1990) MA
standards in many respects but have points in common with them as well.
The first three approaches share with the current standards a reliance
on commuting patterns, but depart from the standards' other criteria
for inclusion of outlying areas in an MA. None of these three
approaches uses population density, presence of urban population, or
rapid population growth to evaluate outlying areas. The fourth approach
uses population density as an indicator of the relative intensity of
social and economic activity rather than attempting to identify
individual cores or to quantify core-outlying area relationships.
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Although these approaches use either counties or census tracts as
the building blocks for statistical areas, each could be implemented
using other geographic units discussed in Part III.D. The population
and commuting thresholds presented for these approaches were selected
by analyzing 1990 population and commuting patterns but are intended
primarily for illustrative purposes and are subject to modification
based on further research and on comments received in response to this
Notice. In general, each approach should be read, considered, and
commented upon in terms of its adequacy in defining and describing
social and economic ties among communities throughout the United
States.
A. A Commuting-Based, County-Level Approach to Defining Metropolitan
and Nonmetropolitan Areas
The MA has been successful as a standard statistical representation
of the social and economic linkages between urban centers and outlying
areas. This success is evident in MAs' continued use across broad areas
of data collection, presentation, and analysis. Nevertheless, some
users of metropolitan and nonmetropolitan area data have strongly
expressed the view that the current standards are overly complex and
burdened with ad hoc components. This first proposed alternative
approach explicitly aims to provide a simpler method of defining
metropolitan and nonmetropolitan regions.
Four kinds of areas are identified in this approach: metropolitan
regions, defined around cores of at least 100,000 persons; mesopolitan
regions, defined around cores of at least 50,000 persons and less than
100,000 persons; and micropolitan regions, defined around cores of at
least 10,000 persons and less than 50,000 persons. Counties not
included in a metropolitan, mesopolitan, or micropolitan region will
constitute rural community areas.
In this approach, counties are the building blocks (see Figure 1).
While this is in keeping with the current standards for most of the
United States, it is a departure from current practice in New England.
Outlying counties are included in metropolitan, mesopolitan, and
micropolitan regions solely on the basis of commuting. Adjacent areas
are combined when commuting rates indicate that the central counties
are linked socially and economically. When metropolitan regions are
combined, the initial metropolitan regions are recognized as primary
metropolitan regions and the combined entity is recognized as a
consolidated metropolitan region.
There are several advantages to this approach. First, counties are
familiar geographic units for which a wide range of statistically
reliable social and economic data are readily available. Second, the
use of counties eases comparison with current and past MA definitions.
Third, because of the greater availability of data for counties than
for sub-county entities, statistical area definitions using counties
can be updated more frequently than others. The potential availability
of nationwide annual county-level commuting data from the Census
Bureau's American Community Survey starting in 2003 raises the
possibility of reviewing all definitions on an annual basis. Under the
current standards, definition activity during intercensal years is
largely limited to cases where new MAs can be designated on the basis
of population estimates or special censuses.
There are, however, disadvantages to this approach as well. Because
of their geographic extent, counties can include territory and
population not functionally integrated with a specific core. The large
geographic size of some counties often poses challenges to measuring
and analyzing localized shifts in populations.
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1. Criteria for Defining Metropolitan Regions Using the Commuting-
Based, County-Level Approach
a. Requirement for Qualification as a Metropolitan Region
Each metropolitan region must include a Census Bureau-defined UA of
at least 100,000 persons.
b. Identification of Central Counties of a Metropolitan Region
The central county or counties of the metropolitan region are those
counties where at least 50 percent of the population resides in the
qualifier UA(s), or that contain at least 50 percent of the population
of the qualifier UA(s). A central county of one metropolitan region
cannot be included as an outlying county in another metropolitan region
in the initial steps for defining metropolitan regions (see IV.A.1.d
below).
c. Inclusion of Outlying Counties
A county is included in the metropolitan region as an outlying
county if at least 25 percent of its resident workers commute to the
central county or counties, or at least 15 percent of its resident
workers commute to the central county or counties and at least 15
percent of its employment is accounted for by workers residing in the
central county or counties.
A county that qualifies as an outlying county of more than one
metropolitan region will be included in the metropolitan region with
which it has the highest commuting exchange. A county that has a
combined commuting exchange with central counties of two or more
metropolitan regions that meets or exceeds the thresholds listed above,
and is contiguous with counties already qualified for inclusion in
those metropolitan regions, will be included in the metropolitan region
with which it has the highest commuting exchange.
The counties included in the metropolitan region must form a
continuous geographic entity. A central county of one metropolitan
region cannot be classified as an outlying county of another
metropolitan region at this stage in the definition process.
d. Combination of Adjacent Metropolitan Regions
Two adjacent metropolitan regions are combined if a central county
of one metropolitan region qualifies as an outlying county of the
other. If two or more metropolitan regions are combined, the
metropolitan regions as defined before the combination will be
designated as primary metropolitan regions and the area resulting from
the combination will be designated as a consolidated metropolitan
region.
e. Titles of Metropolitan Regions
The first name in the title of a metropolitan region or primary
metropolitan region will be the name of the incorporated place with the
largest population in the metropolitan region. The names of up to two
additional incorporated places that are at least one-third the size of
the largest incorporated place will be included in the metropolitan
region or primary metropolitan region title in order of descending
population rank.
The title of a consolidated metropolitan region will include the
names of up to three incorporated places, including the first named
incorporated places in the titles of component primary metropolitan
regions (to a maximum of three) in order of descending population rank
of incorporated places.
2. Criteria for Defining Mesopolitan Regions and Micropolitan Regions
The criteria for defining mesopolitan regions and micropolitan
regions are the same as those for defining metropolitan regions, with
two exceptions: the requirements for qualification and the criteria
pertaining to combining mesopolitan and micropolitan regions. For the
sake of brevity, only the requirements for qualification and criteria
for combining adjacent mesopolitan regions and micropolitan regions are
presented here.
a. Requirements for Qualification of Mesopolitan Regions and
Micropolitan Regions
Each mesopolitan region must contain no part of a metropolitan
region and must include a Census Bureau-defined UA or, outside of UAs,
an incorporated place of at least 50,000 persons and less than 100,000
persons. Each micropolitan area must contain no part of a metropolitan
or mesopolitan region and must include an incorporated place of at
least 10,000 persons and less than 50,000 persons.
b. Combining Adjacent Mesopolitan Regions and Micropolitan Regions
Two adjacent mesopolitan regions (or two adjacent micropolitan
regions) are combined if a central county of one mesopolitan region (or
one micropolitan region) qualifies as an outlying county of the other.
3. Identification of Rural Community Areas
Counties not included in a metropolitan, mesopolitan, or
micropolitan region will form the components of rural community areas.
Contiguous counties will be grouped according to local opinion to form
individual rural community areas within each state, subject to
specified conditions. Titles for rural community areas will be based on
the same criteria used to title metropolitan, mesopolitan, and
micropolitan regions.
B. A Commuting-Based, Census Tract-Level Approach to Defining
Metropolitan and Nonmetropolitan Areas
This second approach employs a two-stage process. First, it
identifies statistical settlement areas based around cores of at least
10,000 persons and their associated daily influence areas. Second, it
identifies metropolitan, mesopolitan, and micropolitan regions. Census
tracts are the geographic units used in this approach. In the first
stage, each statistical settlement area core is identified and linked
with all qualifying statistical settlement area outlying census tracts
on the basis of commuting, creating a system of overlapping areas. Any
core or outlying census tract may be part of two or more statistical
settlement areas. This outcome is meant to depict the overlapping and
nested nature of social and economic linkages between communities
throughout the United States. To account for all the territory of the
United States, rural community areas are identified representing census
tracts not contained within statistical settlement areas or their daily
influence areas.
The second stage of this approach results in a non-overlapping
classification, where each statistical area is mutually exclusive of
all other statistical areas (see Figure 2). Criteria are employed to
assign each census tract to only one metropolitan, mesopolitan, or
micropolitan region. Census tracts not included in any of these areas
are designated as either urban-influenced or rural-influenced,
depending on whether the tracts meet specified criteria relating to
commuting ties with cores of metropolitan, mesopolitan, or micropolitan
regions.
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There are several advantages to this approach. Identifying
overlapping statistical areas in stage one of the delineation process
depicts the multiple linkages among communities. Using census tracts as
building blocks offers greater resolution when analyzing social and
economic patterns and increased precision when defining statistical
areas. Census tracts are defined nationwide using a consistent set of
population guidelines; they are capable of portraying change over time
and across space as their boundaries are updated to reflect population
and settlement pattern changes.
There are disadvantages to this approach as well. First, the
limited availability of economic and demographic data for census tracts
at this time limits their use in analysis. Second, it is more difficult
to compare areas defined using census tracts with MAs defined currently
and in the past using counties. Third, the uncertain availability of
intercensal population estimates for census tracts and the likelihood
that tract-level commuting data from the Census Bureau's American
Community Survey will not be available for all tracts until 2008 could
result in a lack of data to update areas during much of the coming
decade. As a result, metropolitan, mesopolitan, and micropolitan
regions could be defined after the 2000 decennial census, but not
updated until 2008 or later. Fourth, tract-level commuting data from
the 2000 census may be less certain in some nonmetropolitan areas
(where lists of commercial addresses are less complete and geocoding
place-of-work locations therefore is more difficult) than in current
MAs. These uncertainties in the quality of place-of-work geocoding may
reduce the reliability of journey-to-work data for census tracts with
small numbers of commuters.
1. Criteria to Establish Statistical Settlement Areas and Their Daily
Influence Areas
a. Requirement for Qualification as a Statistical Settlement Area
Each statistical settlement area must include either a Census
Bureau-defined UA or, outside of UAs, an incorporated place of at least
10,000 persons.
b. Identification of the Central Core of a Statistical Settlement Area
The core of a statistical settlement area consists of the census
tract(s) in which 20 percent or more of the population falls within the
UA or place identified in the previous step. In addition, at least 70
percent of the workers living in the statistical settlement area core
must work within the core. This last criterion ensures that places that
are strictly ``bedroom communities'' are not identified as cores of
statistical settlement areas.
c. Qualification of Outlying Areas
A census tract is included in a statistical settlement area as an
outlying census tract if at least 25 percent of resident workers in
that tract commute to work in the core, or if at least 25 percent of
the employment in the census tract is accounted for by workers residing
in the core.
d. Titles of Statistical Settlement Areas
The title of a statistical settlement area will include the name of
the incorporated place with the largest population. The names of up to
two additional incorporated places that are at least one-third the size
of the largest place will be included in the statistical settlement
area title in order of descending population rank.
e. Identification of Daily Influence Areas
A census tract is included in the daily influence area of a
statistical settlement area if at least 5 percent but less than 25
percent of the resident workers in that tract commute to work in the
core of the statistical settlement area, or if at least 5 percent but
less than 25 percent of the employment in the census tract is accounted
for by workers residing in the core of the statistical settlement area.
f. Identification of Rural Community Areas
Census tracts not included in any statistical settlement area or
daily influence area will form the components of rural community areas.
Contiguous census tracts will be grouped according to specified
conditions. Titles for rural community areas will be based on the same
criteria used to title statistical settlement areas.
2. Identification of Metropolitan Regions, Mesopolitan Regions, and
Micropolitan Regions
Stage two in this approach provides criteria for identifying
mutually exclusive metropolitan, mesopolitan, and micropolitan regions,
and then classifies the remaining territory as urban-influenced or
rural-influenced.
a. Assigning Territory in Individual Statistical Settlement Areas
A census tract that is part of the core of more than one
statistical settlement area will be assigned to the statistical
settlement area in which it has a larger population within the
associated qualifier UA. A census tract that is in the core of one
statistical settlement area and outlying to one or more other
statistical settlement areas will be included in the statistical
settlement area in which it is part of the core.
A census tract that qualifies for inclusion as an outlying census
tract in more than one statistical settlement area will be assigned to
the statistical settlement area with which it has the highest level of
commuting exchange.
At no time may a statistical settlement area contain discontiguous
census tracts.
b. Combining Statistical Settlement Areas
Statistical settlement areas will be combined if the entire core of
one is integrated with the entire core of the other according to the
commuting thresholds contained in IV.B.1.c above.
c. Qualification of Outlying Census Tracts in Combined Statistical
Settlement Areas
After two or more statistical settlement areas are combined, a
census tract will qualify for inclusion as an outlying census tract in
the combined area if its commuting exchange with the combined
statistical settlement area core(s) meets the criteria outlined in
IV.B.1.c above.
d. Distinguishing Between Metropolitan Regions, Mesopolitan Regions,
and Micropolitan Regions
Any statistical settlement area that contains a Census Bureau-
defined UA of at least 100,000 persons will be designated a
metropolitan region. Any statistical settlement area not identified as
a metropolitan region will be designated as a mesopolitan region if it
contains a Census Bureau-defined UA of at least 50,000 persons and less
than 100,000 persons, or if outside a UA, an incorporated place of at
least 50,000 persons. Any statistical settlement area not identified as
a metropolitan or mesopolitan region will be designated as a
micropolitan region.
e. Titles of Metropolitan Regions, Mesopolitan Regions, and
Micropolitan Regions
Each metropolitan, mesopolitan, or micropolitan region title will
include the name of the incorporated place with the largest population.
The names of up to two additional incorporated places that are at least
one-third the size of the largest place will be included in the
metropolitan, mesopolitan, or micropolitan region title in order of
descending population rank.
[[Page 70547]]
f. Identification of Urban-Influenced and Rural-Influenced Census
Tracts
After all metropolitan, mesopolitan, and micropolitan regions are
defined, any unassigned census tract will be identified as urban-
influenced if at least 5 percent but less than 25 percent of the
resident workers in that tract commute to work in the core of a
metropolitan, mesopolitan, or micropolitan region, or if at least 5
percent but less than 25 percent of the employment in the census tract
is accounted for by workers residing in the core of a metropolitan,
mesopolitan, or micropolitan region. Any census tract that does not
meet these commuting criteria will be classified as rural-influenced.
C. A Directional Commuting, Census Tract-Level Approach to Defining
Metropolitan and Nonmetropolitan Areas
The directional commuting approach also is a census tract-based
system. It relies on the direction and relative strength of commuting
flows to measure social and economic linkages. This concept can be
visualized by imagining typical commuters driving toward a hypothetical
center of metropolitan or nonmetropolitan population in the morning and
away from it in the evening. This approach measures the mean weighted
direction of all commuting flows from a particular tract toward a
population center, rather than measuring the percentage of workers who
commute between central cores and outlying areas (see Figure 3).
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The spatial characteristics of commuting flows never have been
explicitly incorporated into the MA standards, even though the links
between residence and work are inherently spatial. New research using
disaggregated commuting flow data can measure flow characteristics that
have been observed by highway and transit planners for decades.
The directional approach uses the weighted mean direction of
commuting flows by census tract to associate census tracts with
population centers. If the weighted mean flow of a given census tract
is in the direction of a nearby population center, then the tract is
included within the same statistical area as that center.
The directional approach for creating areas has one major
advantage. It can mitigate shortcomings with geocoding place-of-work
data by generalizing commuting flow. Lack of sufficient place-of-work
address information may make the geocoding of tract-level commuting
data from the 2000 decennial census difficult in some nonmetropolitan
areas where lists of commercial addresses are less complete than in
current MAs. Uncertainties in the quality of place-of-work geocoding
may reduce the reliability of sub-county journey-to-work data in the
absence of techniques such as directional statistical methods.
Several disadvantages also are associated with this approach. The
linkage of a census tract with a center of population is subject to a
specified level of angular tolerance and is subject as well to
limitations of the commuting data. Implementation of this approach at
the census tract-level limits annual updating of all metropolitan,
mesopolitan, and micropolitan region definitions using commuting data
from the American Community Survey until at least 2008. Other
disadvantages associated with this approach are similar to those
outlined in the commuting-based, census tract-level approach discussed
above.
1. Criteria for Defining Metropolitan Regions, Mesopolitan Regions, and
Micropolitan Regions
a. Requirements for Qualification
Each metropolitan region must include a Census Bureau-defined UA of
at least 100,000 persons. Each mesopolitan region must contain no part
of a metropolitan region and must include either a Census Bureau-
defined UA of at least 50,000 persons and less than 100,000 persons, or
if outside a UA, an incorporated place of at least 50,000 persons. Each
micropolitan region must contain no part of a metropolitan or
mesopolitan region and must contain an incorporated place of at least
10,000 persons and less than 50,000 persons.
b. Identification of Metropolitan Region, Mesopolitan Region, and
Micropolitan Region Population Centers
Population centers are not cores per se but rather are starting
points for the statistical analysis of commuting flows. The center
point used in measuring directionality of commuting flows toward a
metropolitan region is the ``internal point'' (see Part VII,
``Frequently Used Terms'') of the qualifier UA of 100,000 or more
persons; in the case of mesopolitan regions, the center point used is
the internal point of the qualifier UA of at least 50,000 and less than
100,000 persons, or, outside UAs, the internal point of the most
populous incorporated place having at least 50,000 persons. The center
point used in measuring directionality of commuting flows toward a
micropolitan region is the internal point of the most populous
incorporated place having at least 10,000 persons and less than 50,000
persons.
c. Calculation of Mean Weighted Direction of Commuting Flows
Statistical areas are delineated based on the weighted mean
direction of commuting flows for census tracts with respect to
population centers. A trigonometric formula is used to produce a
weighted mean direction of flow for each tract of residence. Based on
that value, a tract is assigned to the relevant nearby population
center--the UA or place that lies directly in the path of the flow
vector.
To associate census tracts' mean commuting flows with population
centers, it is necessary to specify an angle of inclusion. This means
determining a level of tolerance so that when a directional mean flow
is toward a center of population but does not ``hit'' it directly, the
flow is still associated with the center.
d. Qualification of Census Tracts for Inclusion in a Metropolitan
Region, Mesopolitan Region, or Micropolitan Region
A census tract qualifies for inclusion in a metropolitan,
mesopolitan, or micropolitan region if the largest flow of resident
workers in the census tract is in the direction of the metropolitan,
mesopolitan, or micropolitan region population center. If the flows are
split evenly between two population centers, then local opinion will be
sought to determine the census tract's assignment.
Metropolitan, mesopolitan, and micropolitan regions may not contain
discontiguous census tracts. Under this approach, it is possible that
the mean weighted commuting flows from census tracts close to a
population center may point in a direction away from the center and in
an opposite direction of more remote tracts; in such instances, the
central census tracts will be included in the metropolitan,
mesopolitan, or micropolitan region.
2. Identification of Rural Community Areas
Census tracts not included in a metropolitan, mesopolitan, or
micropolitan region will form the components of rural community areas.
Contiguous census tracts will be grouped according to local opinion,
subject to specified conditions, to form individual rural community
areas within each state.
D. A Comparative Density, County-Level Approach to Defining Statistical
Areas
The three approaches to defining metropolitan and nonmetropolitan
areas just described rely upon commuting as the measure of linkages
between central and outlying areas. Journey-to-work data, however, do
not accurately depict the activity patterns of people without a
regular, fixed work location, such as those who work in sales,
contracting, construction and landscaping trades, and as day- and
itinerant-laborers; also missed are people who work at home (or people
not counted in the workforce). In addition, the daily journey to work
does not describe the many other, non-work activities that define
relationships between individuals and communities, such as trips
associated with shopping, recreation, and social and religious
activities.
Residential population density can serve as a surrogate for other
measures of activity in the absence of nationally consistent and
reliable data sets describing all daily and weekly movements of
individuals. Under this fourth proposed approach, an index is
calculated to reflect relative settlement intensities of counties. The
index number assigned to any given county is determined by multiplying
its population density ranking ratio at the state level with its
ranking ratio at the national level (see below). This provides a
relative measure of activity intensity for comparative purposes
nationwide by taking into account both the national and state contexts.
For instance, Natrona County, Wyoming, which constitutes the Casper
Metropolitan Statistical Area,
[[Page 70550]]
has a low overall population density when compared with most other
counties in the United States, but it would be assigned a value that
also reflects its relative importance within Wyoming.
This approach has several advantages. First, because the
classification is based solely on residential population density, each
county's index value can be calculated quickly after 2000 decennial
census population counts become available (and without waiting for the
later processing of journey-to-work data). Thereafter, the
classification could be updated annually using Census Bureau population
estimates. Second, a wide range of statistically reliable social and
economic data are readily available for counties. Third, the use of
counties facilitates comparability with past MA definitions, even
though this approach differs markedly from the current MA standards.
Fourth, population density can provide information about the intensity
of activity or potential activity within a geographic area.
There are disadvantages to this approach as well. The obvious
drawback is that social and economic linkages between counties are not
described directly. Also, the large land area of some counties tends to
lower overall population densities, and as a result, the index value
for such a county would be relatively low in spite of relatively high
population densities in some parts of the county (San Bernardino
County, California provides a good example). Because population density
is calculated by dividing total population by total land area, local,
sub-county variations in population distribution patterns are not
revealed.
1. Steps in Defining Density-Based Statistical Areas
a. The overall residential population density for each county is
calculated by dividing total population by total land area.
b. All counties within a given state are ranked according to
population density. The highest-density county is assigned the rank N,
where N equals the number of counties in the state. The second-highest-
density county is assigned the rank N-1; third-highest, N-2; and so
forth. For example, if there are 100 counties in a state, then the
county with the highest population density has a rank of 100; the
county with the second highest population density is 99.
c. The state ranking ratio (SRR) of each county is calculated by
dividing the rank of the county by the total number of counties in the
state, using the following equation:
SRR = N [N-1, N-2,...]/N
d. After assigning each county a ranking ratio within the state,
steps a, b, and c are repeated at the national level. In this
iteration, N will represent the number of counties within the United
States (see Figure 4a).
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e. Each county is assigned an index number (I) by multiplying its
state ranking ratio (SRR) and the national ranking ratio (NRR) using
the following equation:
SRR x NRR = I
This produces an index value that can be used to classify and
compare counties throughout the United States in terms of population
density, and thus relative social and economic importance (see Figure
4b).
2. Identification of Residential Density-Based Statistical Areas
This approach would produce index values for all counties that can
be used for classification into as many density-based levels as needed.
A five-level classification that ranges between an index value of 0.0
to .19 at the low end and a value of .80 to 1.0 at the high end
captures most recognizable aspects of the settlement pattern of the
United States. Contiguous counties in the same classification level
then can be identified as individual density-based statistical areas.
3. Titles of Density-Based Statistical Areas
The title of a density-based statistical area will include the name
of the incorporated place with the largest population within that area.
The names of up to two additional incorporated places that are at least
one-third the size of the largest place will be included in the title
in order of descending population rank.
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Part V. Additional Issues for Consideration
This portion of the Notice briefly discusses a few issues that were
not fully addressed in Parts I through IV. These issues are: (1) how to
account for residual areas or exhaust the territory of the Nation
within a statistical area classification; (2) how best to meet data
producers' and users' desires for both county-based and sub-county-
based classifications; and (3) how to identify various settlement
categories, such as inner city, suburban, exurban, and rural areas, in
ways that are useful when analyzing and understanding settlement and
economic patterns within metropolitan and nonmetropolitan areas.
A. Accounting for Residual Areas
Three of the four approaches presented in Part IV for defining
metropolitan and nonmetropolitan areas relied on commuting patterns as
a measure of linkages between outlying and central areas. In all three
of these approaches, however, some residual territory could not be
linked with the central areas. This section discusses methods for
minimizing this residual territory when defining metropolitan and
nonmetropolitan areas. These methods could be used individually or in
combination.
One means of reducing residual territory is to establish a minimum
commuting threshold low enough to ensure that all or nearly all
territory is included within a metropolitan or nonmetropolitan area.
Although this approach would result in areas that account for all the
territory of the Nation, the necessary commuting threshold would be so
low as to call into question the meaningfulness of social and economic
linkages between centers and some outlying areas. As a result, the
conceptual integrity of metropolitan and nonmetropolitan areas would be
compromised.
A second method involves identifying cores of varying minimum sizes
around which metropolitan and nonmetropolitan areas are defined using a
commuting threshold that is sufficiently high to portray meaningful
linkages. This approach does not eliminate the possibility that
residual territory will remain, but reduces the extent of residual
territory to a more meaningful set of areas. This approach is taken in
Parts IV.A and IV.C.
A variant of this second approach reduces the extent of residual
territory by defining influence zones associated with each metropolitan
and nonmetropolitan area, as outlined in Part IV.B. An outlying area
that does not qualify for inclusion in a metropolitan or
nonmetropolitan area could fall within the influence area of a
metropolitan or nonmetropolitan area. Still, the extent of residual
territory is reduced rather than eliminated.
A third approach involves using additional measures of social and
economic linkages, such as newspaper circulation, media market
penetration, and commodity flows, in addition to commuting criteria, to
eliminate residual territory. These other measures would be used as a
last resort after all outlying areas are added to a metropolitan or
nonmetropolitan area on the basis of commuting. This approach
eliminates residual areas by assigning all territory to metropolitan or
nonmetropolitan areas but in doing so establishes a two-tiered system
of qualification. As a result, outlying areas within a particular
metropolitan or nonmetropolitan area may be linked with the core, but
by different criteria.
B. Development of Multiple Sets of Statistical Areas
Some data users have expressed an interest in both a county-based
classification, which offers greater availability of data, and sub-
county-based classifications, which offer greater geographic precision
when defining metropolitan and nonmetropolitan areas. Data providers
and users could choose the classifications that best fit their research
and analysis needs, guided by advice about appropriate uses of each
classification. The substantial downside to this approach is the
potential confusion resulting from the existence of two or more
parallel classifications. Data providers also would be faced with
increased costs for preparing data according to two or more
classifications.
C. Settlement Types Within Metropolitan and Nonmetropolitan Areas
Data providers and users have expressed a desire for official
classification of a variety of settlement types--such as inner city,
inner and outer suburb, and exurban--within metropolitan and
nonmetropolitan areas. A key aspect of this issue has been the lack of
an official designation of what constitutes ``suburban'' territory.
Designations of such settlement types are not essential to defining
social and economic linkages among communities within metropolitan and
nonmetropolitan areas, but they are useful for analyzing and
understanding settlement patterns. A separate settlement classification
system that would be consistent with metropolitan and nonmetropolitan
areas may be appropriate.
Measures that could be employed in delineating inner city, inner
suburban, outer suburban, and exurban territory include, in some
combination:
median housing unit age or year of housing unit
construction;
commuting interchange with central core;
directionality of commuting patterns;
population or housing density; and
road density.
High population density, older housing stock, multidirectional
commuting, and contiguity with the inner city are typical of inner
suburban areas, for example. Outer suburban areas are typified by
moderate population density and age of housing stock and moderately
unidirectional commuting flows. Exurban areas typically are of low
population density, but are distinguished from other sparsely settled
territory by newer housing and unidirectional commuting flows.
Part VI. Sources Cited
Berry, Brian J.L. 1995. ``Capturing Evolving Realities: Statistical
Areas for the American Future.'' In Dahmann, Donald C. and James D.
Fitzsimmons (eds.) Metropolitan and Nonmetropolitan Areas: New
Approaches to Geographical Definition. Working Paper 12. Population
Division, Bureau of the Census.
Bureau of the Census. 1946. ``Report of the Census Bureau
Subcommittee on Metropolitan Areas.''
Castells, Manuel. 1989. The Informational City. Oxford: Basil
Blackwell.
Dear, Michael and Steven Flusty. 1998. ``Postmodern urbanism.''
Annals of the Association of American Geographers Vol. 88 (1): 50-
72.
Fisher, James S. and Ronald L. Mitchelson. 1981. ``Extended and
internal commuting in the transformation of the intermetropolitan
periphery.'' Economic Geography Vol. 57 (3): 189-207.
Fishman, Robert. 1990. ``America's New City,'' The Wilson Quarterly
Vol. 14: 24-48.
Fotheringham, A.S. and P.A. Pellegrini. 1996. ``Disaggregate
Migration Modeling: A comparison of Microdata sources from the U.S.,
U.K., and Canada,'' Area Vol. 28 (3): 347-357.
Gordon, Peter and Harry W. Richardson. 1996. ``Beyond
polycentricity.'' Journal of the American Planning Association Vol.
62 (3): 289-295.
Harvey, David. 1989. The Urban Experience. Baltimore: The Johns
Hopkins University Press.
Lewis, Peirce. 1983. ``The geographic roots of America's urban
troubles.'' University Park, PA: The Pennsylvania State University,
College of Earth and Mineral Sciences, Vol. 52 (3)
Pressman, N. 1985. ``Forces for spatial change.'' In Brotchie, J.,
et al., eds. The
[[Page 70555]]
Future of Urban Form. London: Croom Helm.
Part VII. Frequently Used Terms
(An asterisk (*) denotes terms proposed for the purposes of this
Notice)
Census county division (CCD)--A statistical subdivision of a
county, established cooperatively by the Census Bureau and state and
local government authorities, for the presentation of decennial census
data in 21 states where minor civil divisions either do not exist or
are unsatisfactory for the collection, presentation, and analysis of
census statistics.
Census tract--A small, relatively permanent statistical subdivision
of a county, delineated cooperatively by local statistical areas
program participants and the Census Bureau. Census tracts for the 2000
decennial census will have between 1,500 and 8,000 inhabitants.
Central city--The largest city of a metropolitan statistical area
or a consolidated metropolitan statistical area, plus additional cities
that meet specified statistical criteria.
Central county--The county or counties of an MA containing the
largest city or urbanized area, and to and from which commuting is
measured to determine qualification of outlying counties.
Consolidated metropolitan statistical area (CMSA)--A geographic
entity defined by OMB for statistical purposes. An area becomes a CMSA
if it meets the requirements to qualify as a metropolitan statistical
area, has a population of 1,000,000 or more, contains component parts
that qualify as primary metropolitan statistical areas (PMSAs), and
local opinion favors PMSA designation. Whole counties are components of
CMSAs, except in New England, where they are composed of cities and
towns.
County subdivision--A legal (minor civil division) or statistical
(census county division) subdivision of a county.
* Daily influence area (DIA)--Territory that is minimally
associated with a statistical settlement area.
Functional integration--The linkage of geographic entities
according to patterns of social or economic interactions.
Geocoding--The practice of assigning data to a specific geographic
location and a set of geographic codes.
* Geographic building block--The geographic unit, such as census
tract, county subdivision, or county, that forms the basic geographic
component of a metropolitan or nonmetropolitan area.
Internal point--A point, generally marking the central location
within a geographic entity.
* Mesopolitan region--A geographic entity containing a core area of
at least 50,000 persons and less than 100,000 persons plus adjacent
communities having a high degree of social and economic integration
with that core.
Metropolitan area (MA)--A collective term, established by OMB and
used for the first time in 1990, to refer to metropolitan statistical
areas, consolidated metropolitan statistical areas, and primary
metropolitan statistical areas.
* Metropolitan region--A geographic entity containing a core area
of at least 100,000 persons plus adjacent communities having a high
degree of social and economic integration with that core.
Metropolitan statistical area (MSA)--A geographic entity, defined
by OMB for statistical purposes, containing a core area with a large
population center and adjacent communities having a high degree of
social and economic integration with that center. Qualification of an
MSA requires the presence of a city with 50,000 or more inhabitants, or
the presence of an urbanized area and a total population of at least
100,000 (75,000 in New England). MSAs are composed of entire counties,
except in New England where the components are cities and towns.
* Micropolitan region--A geographic entity containing a core area
of at least 10,000 persons and less than 50,000 persons plus adjacent
communities having a high degree of social and economic integration
with that core.
Minor civil division (MCD)--A type of governmental unit that is the
primary legal subdivision of a county, created to govern or administer
an area rather than a specific population. MCDs are recognized by the
Census Bureau as the county subdivisions of 28 states and the District
of Columbia.
New England county metropolitan area (NECMA)--County-based areas
defined by OMB to provide an alternative to the city-and town-based
metropolitan statistical areas and consolidated metropolitan
statistical areas in New England.
Outlying county--The county or counties that qualify for inclusion
in a metropolitan area based on commuting ties with central counties
and other specified measures of metropolitan character.
Population density--A measure of the number of people per
geographic unit, usually expressed in terms of people per square mile
or per square kilometer.
Population growth rate--The change in a population during a given
period, as determined by births, deaths, and net migration, and
commonly expressed as a percentage of the initial population.
Primary metropolitan statistical area (PMSA)--A county or group of
counties that meet specified statistical criteria and receive local
opinion support for recognition as a component of a consolidated
metropolitan statistical area under OMB's metropolitan area standards.
Qualifier urbanized area--The urbanized area that results in
qualification of a metropolitan area.
* Rural community area (RCA)--A geographic entity containing
geographic units not included within a statistical settlement area,
metropolitan region, mesopolitan region, or micropolitan region, nor
within associated influence areas, and defined partly in accordance
with local opinion.
* Statistical settlement area (SSA)--A geographic entity containing
a core of at least 10,000 persons and surrounding communities that are
linked socially and economically, as measured by commuting.
Urbanized area (UA)--A statistical geographic area defined by the
Census Bureau, consisting of a central place(s) and adjacent densely
settled territory that together contain at least 50,000 people,
generally with an overall population density of at least 1,000 people
per square mile.
Donald R. Arbuckle,
Acting Administrator, Office of Information and Regulatory Affairs.
Appendix A--Revised Standards for Defining Metropolitan Areas in
the 1990s
Part I. Overview
Part I gives the structure of this document. Part II describes
the changes from the previous standards and the reasons for the
changes. Part III gives the official metropolitan area standards for
the 1990s. Part IV gives a list of definitions of key terms and
guidelines used in the standards. The terms in Part IV are listed in
alphabetical order.
In Part III, sections 1 through 7 contain the basic standards
for defining metropolitan statistical areas in all States except the
New England States. They specify standards for determining: how
large a population nucleus must be to qualify as an MSA (section 1);
the central county/counties of the MSA (section 2); additional
outlying counties with sufficient metropolitan character and
integration to the central county/counties to qualify for inclusion
in the MSA (section 3); the central city or cities of each MSA
(section 4); whether two adjacent MSAs qualify to be combined
(section 5); four categories or levels of MSAs, based on the total
population
[[Page 70556]]
of each area (section 6); and the title of each MSA (section 7).
Sections 8 through 10 provide a framework for identifying PMSAs
within an MSA of at least one million population. If such PMSAs are
identified, the larger area of which they are components is
designated a CMSA.
Sections 11 through 15 apply only to the New England States. In
these States, metropolitan areas are composed of cities and towns
rather than whole counties. Sections 11, 12, and 13 specify how New
England MSAs are defined and titled. Sections 14 and 15 show how
CMSAs and PMSAs are defined and titled.
Section 16 sets forth the standards for updating definitions
between decennial censuses.
Part II. Changes in the Standards for the 1990s
The metropolitan area standards for the 1990s generally reflect
a continuity with those adopted for the 1980s, and they maintain the
basic concepts originally developed in 1950. The substantive
modifications of the standards are specified below. Some other
modifications have been made that involve word changes but not
substance.
1. Effective April 1, 1990, the set of areas known as
Metropolitan Statistical Areas (MSAs), Primary Metropolitan
Statistical Areas (PMSAs), and Consolidated Metropolitan Statistical
Areas (CMSAs) will be designated collectively as Metropolitan Areas
(MAs). The reason for this change is to distinguish between the
individual areas known as MSAs and the set of all areas.
2. A small group of counties containing a portion of a city's
urbanized area will now qualify as outlying, even though their
population density is relatively low. This change allows the
inclusion in metropolitan areas of entire urbanized areas.
3. Counties included solely because they contain at least 2,500
population in a central city now will be assigned outlying county
rather than central county status (section 3A(6)). This will ensure
that additional outlying counties will not be designated solely
because of commuting with a county including a small portion of the
central city.
4. The largest city, and other cities of at least 15,000 in a
secondary noncontiguous urbanized area within a metropolitan
statistical area, now may be identified as central cities, provided
that the other requirements for central cities are met (sections 4E
and 4F). This allows cities that perform as central cities in
secondary noncontiguous urbanized areas to be designated as central
cities.
5. The employment criterion for inclusion in an area title is
deleted; only the population criteria remain (section 7). This
change was made because in 1980 only one area qualified based on
employment.
6. A place qualifying as a central city but with less than one-
third the population of the largest city may now be included in the
metropolitan statistical area title if strongly supported by local
opinion (section 7A(3)). Communities often have strong views on the
way their MSAs are titled. This change allows taking these views
into account.
7. The presence of a small portion (less than 2,500 population)
of the largest city of a CMSA in a county no longer precludes
consideration of that county as a PMSA (section 8B(4)). Such a small
portion of a city does not alter the characteristics of the PMSA.
8. We have added standards for intercensal updating of
metropolitan areas (section 16). These standards existed separately,
but we felt they should be incorporated into the published
standards.
9. Qualifying percentages and ratios are considered to one
decimal and ratios on the basis of two decimals (in each case, one
less decimal than previously) (Part IV). The previous standards
implied a level of accuracy that was not justified.
10. Several technical adjustments were made (Part IV). For
example, localities in Puerto Rico officially known as aldeas in
1980, are now termed comunidades.
Part III. Official Standards for Metropolitan Areas
Basic Standards. Sections 1 through 7 apply to all States except
the six New England States, that is, Connecticut, Maine,
Massachusetts, New Hampshire, Rhode Island, and Vermont. They also
apply to Puerto Rico.1
---------------------------------------------------------------------------
\1\ Those provisions of sections 1 through 7 that are applicable
to New England are specified in the standards relating to New
England (sections 11 through 15).
---------------------------------------------------------------------------
Section 1. Population Size Requirements for Qualification
Each metropolitan statistical area must include:
A. A city of 50,000 or more population, or 2
---------------------------------------------------------------------------
\2\ An MSA designated on the basis of census data according to
standards in effect at the time of designation will not be
disqualified on the basis of lacking a city of at least 50,000
population.
---------------------------------------------------------------------------
B. A Census Bureau defined urbanized area of at least 50,000
population, provided that the component county/counties of the
metropolitan statistical area have a total population of at least
100,000.3
---------------------------------------------------------------------------
\3\ An MSA designated on the basis of census data according to
standards in effect at the time of designation will not be
disqualified on the basis of lacking an urbanized area of at least
50,000 or a total MSA population of at least 100,000.
---------------------------------------------------------------------------
Section 2. Central Counties
The central county/counties of the MSA are:
A. Those counties that include a central city (see section 4) of
the MSA, or at least 50 percent of the population of such a city,
provided the city is located in a qualifier urbanized area; and B.
Those counties in which at least 50 percent of the population lives
in the qualifier urbanized area(s).
Section 3. Outlying Counties
A. An outlying county is included in an MSA if any one of the
six following conditions is met:
(1) At least 50 percent of the employed workers residing in the
county commute to the central county/counties, and either
(a) The population density of the county is at least 25 persons
per square mile, or
(b) At least 10 percent, or at least 5,000, of the population
lives in the qualifier urbanized area(s);
(2) From 40 to 50 percent of the employed workers commute to the
central county/counties, and either
(a) The population density is at least 35 persons per square
mile, or
(b) At least 10 percent, or at least 5,000, of the population
lives in the qualifier urbanized area(s);
(3) From 25 to 40 percent of the employed workers commute to the
central county/counties and either the population density of the
county is at least 50 persons per square mile, or any two of the
following conditions exist:
(a) Population density is at least 35 persons per square mile,
(b) At least 35 percent of the population is urban,
(c) At least 10 percent, or at least 5,000, of the population
lives in the qualifier urbanized area(s);
(4) From 15 to 25 percent of the employed workers commute to the
central county/counties,4 the population density of the
county is at least 50 persons per square mile, and any two of the
following conditions also exist:
---------------------------------------------------------------------------
\4\ Also accepted as meeting this commuting requirement are:
(a) The number of persons working in the county who live in the
central county/counties is equal to at least 15 percent of the
number of employed workers living in the county; or
(b) The sum of the number of workers commuting to and from the
central county/counties is equal to at least 20 percent of the
number of employed workers living in the county.
---------------------------------------------------------------------------
(a) Population density is at least 60 persons per square mile,
(b) At least 35 percent of the population is urban,
(c) Population growth between the last two decennial censuses is
at least 20 percent,
(d) At least 10 percent, or at least 5,000, of the population
lives in the qualifier urbanized area(s);
(5) From 15 to 25 percent of the employed workers commute to the
central county/counties,4 the population density of the
county is less than 50 persons per square mile, and any two of the
following conditions also exist:
(a) At least 35 percent of the population is urban,
(b) Population growth between the last two decennial censuses is
at least 20 percent,
(c) At least 10 percent, or at least 5,000, of the population
lives in the qualifier urbanized area(s);
(6) At least 2,500 of the population lives in a central city of
the MSA located in the qualifier urbanized area(s).5
---------------------------------------------------------------------------
\5\ See section 4 for the standards for identifying central
cities.
---------------------------------------------------------------------------
B. If a county qualifies on the basis of commuting to the
central county/counties of two different MSAs, it is assigned to the
area to which commuting is greatest, unless the relevant commuting
percentages are within 5 points of each other, in which case local
opinion about the most appropriate assignment will be considered.
[[Page 70557]]
C. If a county qualifies as a central county under section 2 and
also qualifies as an outlying county of another metropolitan area
under section 3A on the basis of commuting to (or from) another
central county, both counties become central counties of a single
merged MSA.
Section 4. Central Cities
The central city/cities of the MSA are:
A. The city with the largest population in the MSA;
B. Each additional city with a population of at least 250,000 or
with at least 100,000 persons working within its limits;
C. Each additional city with a population of at least 25,000, an
employment/residence ratio of at least 0.75, and at least 40 percent
of its employed residents working in the city;
D. Each city of 15,000 to 24,999 population that is at least
one-third as large as the largest central city, has an employment/
residence ratio of at least 0.75, and has at least 40 percent of its
employed residents working in the city;
E. The largest city in a secondary noncontiguous urbanized area,
provided it has at least 15,000 population, an employment/residence
ratio of at least 0.75, and has at least 40 percent of its employed
residents working in the city;
F. Each additional city in a secondary noncontiguous urbanized
area that is at least one-third as large as the largest central city
of that urbanized area, that has at least 15,000 population and an
employment/residence ratio of at least 0.75, and that has at least
40 percent of its employed residents working in the city.
Section 5. Combining Adjacent Metropolitan Statistical Areas
Two adjacent MSAs defined by sections 1 through 4 are combined
as a single MSA provided:
A. The total population of the combination is at least one
million, and:
(1) The commuting interchange between the two MSAs is equal to:
(a) At least 15 percent of the employed workers residing in the
smaller MSA, or
(b) At least 10 percent of the employed workers residing in the
smaller MSA, and
(i) The urbanized area of a central city of one MSA is
contiguous with the urbanized area of a central city of the other
MSA, or
(ii) A central city in one MSA is included in the same urbanized
area as a central city in the other MSA; and
(2) At least 60 percent of the population of each MSA is urban.
B. The total population of the combination is less than one
million and:
(1) Their largest central cities are within 25 miles of one
another, or their urbanized areas are contiguous; and
(2) There is definite evidence that the two areas are closely
integrated with each other economically and socially; and
(3) Local opinion in both areas supports the combination.
Section 6. Levels
A. Each MSA defined by sections 1 through 5 is categorized in
one of the following levels based on total population:
Level A--MSAs of 1 million or more;
Level B--MSAs of 250,000 to 999,999;
Level C--MSAs of 100,000 to 249,999; and
Level D--MSAs of less than 100,000.
B. Areas assigned to Level B, C, or D are designated as MSAs.
Areas assigned to Level A are not finally designated or titled until
they have been reviewed under sections 8 and 9.
Section 7. Titles of Metropolitan Statistical Areas (MSAs)
A. The title of an MSA assigned to Level B, C, or D includes the
name of the largest central city, and up to two additional city
names, as follows:
(1) The name of each additional city with a population of at
least 250,000;
(2) The names of the additional cities qualified as central
cities by section 4, provided each is at least one-third as large as
the largest central city; and
(3) The names of other central cities (up to the maximum of two
additional names) if local opinion supports the resulting title.
B. An area title that includes the names of more than one city
begins with the name of the largest city and lists the other cities
in order of their population according to the most recent national
census.6
---------------------------------------------------------------------------
\6\ The largest central city included in an existing
metropolitan area title will not be resequenced in or displaced from
that title until both its population and the number of persons
working within its limits are exceeded by those of another city
qualifying for the area title.
---------------------------------------------------------------------------
C. In addition to city names, the title contains the name of
each State in which the MSA is located.
Standards for Primary and Consolidated Metropolitan Statistical Areas
(PMSAs and CMSAs).
Sections 8 through 10 apply to Level A metropolitan statistical
areas outside New England.
Section 8. Qualifications for Designation of Primary Metropolitan
Statistical Areas (PMSAs)
Within a Level A MSA:
A. Any county or group of counties that was designated an SMSA
on January 1, 1980, will be designated a PMSA, unless local opinion
does not support its continued separate designation for statistical
purposes.
B. Any additional county/counties for which local opinion
strongly supports separate designation will be considered for
identification as a PMSA, provided one county is included that has:
(1) At least 100,000 population;
(2) At least 60 percent of its population urban;
(3) Less than 35 percent of its resident workers working outside
the county; and
(4) Less than 2,500 population of the largest central city of
the Level A MSA.
C. A set of two or more contiguous counties for which local
opinion strongly supports separate designation, and that may include
a county or counties that also could qualify as a PMSA under section
8B, also will be considered for designation as a PMSA, provided:
(1) Each county meets requirements (1), (2), and (4) of section
8B, and has less than 50 percent of its resident workers working
outside the county;
(2) Each county in the set has a commuting interchange of at
least 20 percent with the other counties in the set; and
(3) The set of two or more contiguous counties has less than 35
percent of its resident workers working outside its area.
D. Each county in the interim Level A MSA, not included within a
central core under sections 8A through C, is assigned to the
contiguous PMSA to whose central core commuting is greatest,
provided this commuting is:
(1) At least 15 percent of the county's resident workers;
(2) At least 5 percentage points higher than the commuting flow
to any other PMSA central core that exceeds 15 percent; and
(3) Larger than the flow to the county containing the Level A
MSA's largest central city.
E. If a county has qualifying commuting ties to two or more PMSA
central cores and the relevant values are within 5 percentage points
of each other, local opinion is considered before the county is
assigned to any PMSA.
F. The interim PMSA definitions resulting from these procedures
(including possible alternative definitions, where appropriate) are
submitted to local opinion. Final definitions of PMSAs are made
based on these standards, and a review of local opinion.
G. If any primary metropolitan statistical area or areas have
been recognized under sections 8 A through F, the balance of the
Level A metropolitan statistical area, which includes its largest
central city, also is recognized as a primary metropolitan
statistical area.7
---------------------------------------------------------------------------
\7\ If section 8G would result in the balance of the Level A
metropolitan statistical area including a noncontiguous county, this
county will be added to the contiguous primary metropolitan
statistical area to which the county has the greatest commuting.
---------------------------------------------------------------------------
Section 9. Levels and Titles of Primary Metropolitan Statistical
Areas
A. PMSAs are categorized in one of four levels according to
total population, following the standards of Section 6A.
B. PMSAs are titled in either of two ways:
(1) Using the names of up to three cities in the primary
metropolitan statistical area that have qualified as central cities
of the Level A MSA under section 4, following the standards of
section 7 for selection and sequencing; or
(2) Using the names of up to three counties in the PMSA,
sequenced in order from largest to smallest population.
C. Local opinion on the most appropriate title will be
considered.
[[Page 70559]]
Section 10. Designation and Titles of Consolidated Metropolitan
Statistical Areas
A. A Level A metropolitan statistical area in which two or more
primary metropolitan statistical areas are identified by section 8
is designated a consolidated metropolitan statistical area. If no
primary metropolitan statistical areas are defined, the Level A area
remains a metropolitan statistical area, and is titled according to
section 7.
B. Consolidated metropolitan statistical areas are titled
according to the following guidelines. Local opinion is always
sought before determining the title of a consolidated metropolitan
statistical area.
(1) The title of each area includes up to three names, the first
of which is always the name of the largest central city in the area.
A change in the first-named city in the title will not be made until
both its population and the number of persons working within its
limits are exceeded by the those of another city in the consolidated
area.
(2) The preferred basis for determining the two remaining names
is:
(a) The first city (or county) name that appears in the title of
the remaining primary metropolitan statistical area with the largest
total population; and
(b) The first city (or county) name that appears in the title of
the primary metropolitan statistical area with the next largest
total population.
(3) A regional designation may be substituted for the second
and/or third names in the title if there is strong local support and
the proposed designation is unambiguous and suitable for inclusion
in a national standard.
Standards for New England
In the six New England States of Connecticut, Maine,
Massachusetts, New Hampshire, Rhode Island, and Vermont, the cities
and towns are administratively more important than the counties, and
a wide range of data is compiled locally for these entities.
Therefore, the cities and towns are the units used to define
metropolitan areas in these States. The New England standards are
based primarily on population density and commuting. As a basis for
measuring commuting, a central core is first defined for each New
England urbanized area.
In New England, there is an alternative county-based definition
of MSAs known as the New England County Metropolitan Areas (NECMAs)
(see Part IV).
Section 11. New England Central Cores
A central core is determined in each New England urbanized area
through the definition of two zones.
A. Zone A comprises:
(1) The largest city in the urbanized area;
(2) Each additional place in the urbanized area or in a
contiguous urbanized area that qualifies as a central city under
section 4, provided at least 15 percent of its resident employed
workers work in the largest city in the urbanized area;8
---------------------------------------------------------------------------
\8\ Also accepted as meeting this commuting requirement are:
(a) The number of persons working in the subject city or town
who live in the specified city or area is equal to at least 15
percent of the employed workers living in the subject city or town;
or
(b) The sum of the number of workers commuting to and from the
specified city or area is equal to at least 20 percent of the
employed workers living in the subject city or town.
---------------------------------------------------------------------------
(3) Each additional city or town at least 50 percent of whose
population lives in the urbanized area or a contiguous urbanized
area, provided at least 15 percent of its resident employed workers
work in the largest city in the urbanized area plus any additional
central cities qualified by section 11A(2).8
B. Zone B comprises each city or town that has:
(1) At least 50 percent of its population living in the
urbanized area or in a contiguous urbanized area; and
(2) At least 15 percent of its resident employed workers working
in Zone A.8
C. The central core comprises Zone A, Zone B, and any city or
town that is physically surrounded by Zones A or B, except that
cities or towns that are not contiguous with the main portion of the
central core are not included.
D. If a city or town qualifies under sections 11A through C for
more than one central core, it is assigned to the core to which
commuting is greatest, unless the relevant commuting percentages are
within 5 points of each other, in which case local opinion as to the
most appropriate assignment also is considered.
Section 12. Outlying Cities and Towns
A. A city or town contiguous to a central core as defined by
section 11 is included in its metropolitan statistical area if:
(1) It has a population density of at least 60 persons per
square mile and at least 30 percent of its resident employed workers
work in the central core; or
(2) It has a population density of at least 100 persons per
square mile and at least 15 percent of the employed workers living
in the city or town work in the central core.9
---------------------------------------------------------------------------
\9\ This commuting requirement is also considered to have been
met if:
(a) The number of persons working in the city or town who live
in the central core is equal to at least 15 percent of the employed
workers living in the city or town.
(b) The sum of the number of workers commuting to and from the
central core is equal to at least 20 percent of the employed workers
living in the city or town.
---------------------------------------------------------------------------
B. If a city or town has the qualifying level of commuting to
two different central cores, it is assigned to the metropolitan
statistical area to which commuting is greatest, unless the relevant
commuting percentages are within 5 points of each other, in which
case local opinion as to the most appropriate assignment also is
considered.
C. If a city or town has the qualifying level of commuting to a
central core, but has greater commuting to a nonmetropolitan city or
town, it will not be assigned to any metropolitan statistical area
unless the relevant commuting percentages are within 5 points of
each other, in which case local opinion as to the most appropriate
assignment will also be considered.
Section 13. Applicability of Basic Standards to New England
Metropolitan Statistical Areas
A. An area defined by sections 11 and 12 qualifies as a
metropolitan statistical area if it contains a city of at least
50,000 population or has a total population of at least
75,000.10
---------------------------------------------------------------------------
\10\ A New England metropolitan statistical area designated on
the basis of census data according to standards in effect at the
time of designation will not be disqualified on the basis of lacking
a total population of at least 75,000.
---------------------------------------------------------------------------
B. The area's central cities are determined according to the
standards of section 4.
C. Two adjacent New England metropolitan statistical areas are
combined as a single metropolitan statistical area provided the
conditions of section 5A are met. Section 5B is not applied in New
England.
D. Each New England metropolitan statistical area defined by
sections 13A through C is categorized in one of the four levels
specified in section 6A. Areas assigned to Level B, C, or D are
designated as metropolitan statistical areas. Areas assigned to
Level A are not finally designated until they have been reviewed
under sections 14 and 15.
E. New England metropolitan statistical areas are titled
according to the standards of section 7.
Section 14. Qualification for Designation of Primary Metropolitan
Statistical Areas (PMSAs)
The following are qualifications within a Level A metropolitan
statistical area in New England:
A. Any group of cities and towns that was recognized as a
standard metropolitan statistical area on January 1, 1980, will be
recognized as a primary metropolitan statistical area, unless local
opinion does not support its continued separate recognition for
statistical purposes.
B. Any additional group of cities and/or towns for which local
opinion strongly supports separate recognition will be considered
for designation as a primary metropolitan statistical area, if:
(1) The total population of the group is at least 75,000;
(2) It includes at least one city with a population of 15,000 or
more, an employment/residence ratio of at least 0.75, and at least
40 percent of its employed residents working in the city;
(3) It contains a core of communities, each of which has at
least 50 percent of its population living in the urbanized area, and
which together have less than 40 percent of their resident workers
commuting to jobs outside the core; and
(4) Each community in the core also has:
(a) At least 5 percent of its resident workers working in the
component core city identified in section 14B(2), or at least 10
percent working in the component core city or in places already
qualified for this core; this percentage also must be greater than
that to any other core or to the largest city of the Level A MSA;
and
(b) At least 20 percent commuting interchange with the component
core city together with other cities and towns already
[[Page 70559]]
qualified for the core; this interchange also must be greater than
with any other core or with the largest city of the Level A MSA.
C. Contiguous component central cores may be merged as a single
core if:
(1) Section 14B would qualify the component core city of one
core for inclusion in the other core; and
(2) There is substantial local support for treating the two as a
single core.
D. Each city or town in the interim Level A MSA not included in
a core under sections 14A through C is assigned to the contiguous
PMSA to whose core its commuting is greatest, if:
(1) This commuting is at least 15 percent of the place's
resident workers; and
(2) The commuting interchange with the core is greater than with
the Level A MSA's largest city.
E. If a city or town has qualifying commuting ties to two or
more cores and the relevant values are within 5 percentage points of
each other, local opinion is considered before the place is assigned
to any PMSA.
F. The interim PMSA definitions resulting from these procedures
(including possible alternative definitions, where appropriate) are
submitted to local opinion. Final definitions of PMSAs are made
based on these standards, and a review of local opinion.
G. If any primary metropolitan statistical area or areas have
been recognized under sections 14A through F, the balance of the
Level A metropolitan statistical area, which includes its largest
city, also is recognized as a primary metropolitan statistical area.
11
---------------------------------------------------------------------------
\11\ If section 14G results in the balance of the Level A
metropolitan statistical area including a noncontiguous city or
town, this place will be added to the contiguous primary
metropolitan statistical area to which it has the greatest
commuting.
---------------------------------------------------------------------------
Section 15. Levels and Titles of Primary Metropolitan Statistical
Areas and Consolidated Metropolitan Statistical Areas in New
England
A. New England primary metropolitan statistical areas are
categorized in one of four levels according to total population,
following section 6A.
B. New England primary metropolitan statistical areas are titled
using the names of up to three cities in the primary area that have
qualified as central cities under section 4, following the standards
of section 7 for selection and sequencing.
C. Each Level A metropolitan statistical area in New England in
which primary metropolitan statistical areas have been identified
and supported by local opinion (according to section 14) is
designated a consolidated metropolitan statistical area. Titles of
New England consolidated metropolitan statistical areas are
determined following the standards of section 10. A Level A
metropolitan statistical area in which no primary metropolitan
statistical areas have been defined is designated a metropolitan
statistical area, and is titled according to the rules of section 7.
Section 16. Intercensal Metropolitan Area Changes
A. Definitions.
(1) A Census Count is a special census conducted by the U.S.
Bureau of the Census or a decennial census count updated to reflect
annexations and boundary changes since the census.
(2) A Census Bureau Estimate is a population estimate issued by
the U.S. Bureau of the Census for an intercensal year.
B. Qualification for Designation of a Metropolitan Statistical
Area. The qualifications for designation are as follows:
(1) A city reaches 50,000 population according to a Census Count
or Census Bureau Estimate.
(2) A nonmetropolitan county containing an urbanized area (UA)
defined by the Bureau of the Census at the most recent decennial
census reaches 100,000 population according to a Census Count or
Census Bureau Estimate. If the potential metropolitan statistical
area centered on the urbanized area consists of two or more
counties, their total population must reach 100,000. In New England,
the cities and towns qualifying for the potential metropolitan
statistical area must reach a total population of 75,000.
(3) The Census Bureau defines a new urbanized area based on a
Census Count after the decennial census, and the potential
metropolitan statistical area containing the urbanized area meets
the population requirements of section 16.B(2).
If a metropolitan statistical area is qualified intercensally by
a Census Bureau Estimate, the qualification must be confirmed by the
next decennial census, or the area is disqualified.
C. Addition of Counties. Counties are not added to metropolitan
statistical areas between censuses, except as follows:
(1) If a central city located in a qualifier urbanized area
extends into a county not included in the metropolitan statistical
area and the population of the portion of the city in the county
reaches 2,500 according to a Census Count, then the county qualifies
as an outlying county and is added to the metropolitan statistical
area.
(2) If a metropolitan statistical area qualified intercensally
under section 16B meets the requirements of section 5B for
combination with a metropolitan statistical area already recognized,
that combination may take place and thereby alter the definition of
the existing metropolitan statistical area.
D. Qualification for Designation of a Central City. A Census
Count serves to qualify a central city (section 4) that has failed
to qualify solely because its population was smaller than required--
for example, it did not qualify as the largest city of the
metropolitan statistical area (section 4A), or was below 250,000
(4B), below 25,000 (4C), or below 15,000 (4D-F). If qualification
requires comparison with the population of another city, comparison
is made with the latest available Census Bureau Estimate or Census
Count of the population of the other city.
E. Area Titles. The title of a metropolitan statistical area,
primary metropolitan statistical area, or consolidated metropolitan
statistical area may be altered to include the name of a place that
has newly qualified as a central city on the basis described in
section 16D, and that also meets the requirements of section 7. Such
a change is made by adding the new name at the end of the existing
title, but cannot be made if the title already contains three names.
Names in area titles are not resequenced except on the basis of a
decennial census.
F. Other aspects of the metropolitan area definitions are not
subject to change between censuses.
Part IV. General Procedures and Definitions
This part specifies certain important guidelines regarding the
data and procedures used in implementing the standards. It also
gives definitions for ``city,'' ``urbanized area,'' and other key
terms.
General Procedures
Local Opinion. Local opinion is the reflection of the views of
the public on specified matters relating to the application of the
standards for defining metropolitan areas, obtained through the
appropriate congressional delegation, and considered after the
thresholds in the statistical standards have been met. Members of
the congressional delegation will be urged to contact a wide range
of groups in their communities, including business or other leaders,
Chambers of Commerce, planning commissions, and local officials, to
solicit comments on specified issues. OMB will consider all
pertinent local opinion material on these matters in determining the
final definition and title of the area. After a decision has been
made on a particular matter, OMB will not again request local
opinion on the same question until after the next national census.
Local opinion is considered for:
(a) Combining two adjacent metropolitan statistical areas (of
less than one million population) whose central cities are within 25
miles of each other (section 5B).
(b) Metropolitan statistical area titles (section 7A(3)).
(c) Identifying primary metropolitan statistical areas within
consolidated metropolitan statistical areas (sections 8 and 14).
(d) Titling primary metropolitan statistical areas (sections 9
and 15).
(e) Titling consolidated metropolitan statistical areas after
identification of the largest city (sections 10 and 15).
(f) Assignment of a county or place that, based on commuting, is
eligible for inclusion in more than one area (sections 3B, 8E, 11D,
12B and 12C, and 14E).
New England County Metropolitan Areas (NECMAs). The New England
County Metropolitan Areas (NECMAs) provide an alternative to the
official city-and-town-based metropolitan statistical areas in that
region for the convenience of data users who desire a county-defined
set of areas.
The NECMA for a metropolitan statistical area includes:
1. The county containing the first-named city in the
metropolitan statistical area title. In some cases, this county will
contain the
[[Page 70560]]
first-named city of one or more additional metropolitan statistical
areas.
2. Each other county which has at least half of its population
in the metropolitan statistical area(s) whose first-named cities are
in the county identified in step 1.
The NECMA for a consolidated metropolitan statistical area also
is defined by the above rules, except that the New England portion
of the consolidated metropolitan statistical area which includes New
York City is used as the basis for defining a separate NECMA. No
NECMAs are defined for individual primary metropolitan statistical
areas.
The central cities of a NECMA are those cities in the NECMA that
qualify as central cities of a metropolitan statistical area or
consolidated metropolitan statistical area; some central cities may
not be included in any NECMA title.
The title of the NECMA includes each city in the NECMA that is
the first-named title city of a metropolitan area, in descending
order of metropolitan statistical area (or primary metropolitan
statistical area) total population. Other cities that appear in
metropolitan area titles are included only if the resulting NECMA
title would consist of no more than three names.
Levels for NECMAs are determined following section 6A of the
official metropolitan area standards.
Percentages, Densities, and Ratios. Percentages and densities
are computed to the nearest tenth (one decimal); ratios are computed
to the nearest one hundredth (two decimals); and comparisons between
them are made on that basis.
Populations. In general, the population data required by the
standards are taken from the most recent national census. However,
in certain situations either (1) the results of a special census
taken by the Bureau of the Census, or (2) a population estimate
published by the Bureau of the Census may be used to meet the
requirements of the standards (section 16).
Review of Cutoffs and Values. OMB has promulgated these
standards with the advice of the Federal Executive Committee on
Metropolitan Areas, following an open period of public comment.
After the 1990 decennial census data become available, the Federal
Executive Committee will review the census data and their
implications for the cutoffs and values used in the standards, and
will report to OMB the results of its review.
Definitions of Key Terms
Central Core--The counties (or cities and towns in New England)
that are eligible for initial delineation as primary metropolitan
statistical areas because they meet specified population and
commuting criteria.
City--The term ``city'' includes:
(a) Any place incorporated under the laws of its State as a
city, village, borough (except in Alaska), or town (except in the
New England States, New York, and Wisconsin). These comprise the
category of incorporated places recognized in Bureau of the Census
publications.
(b) In Hawaii, any place recognized as a census designated place
by the Bureau of the Census in consultation with the State
government; in Puerto Rico, any place recognized as a zona urbana or
a comunidad by the Bureau of the Census in consultation with the
Commonwealth government. (Hawaii and Puerto Rico do not have legally
defined cities corresponding to those of most States.)
(c) Any township in Michigan, Minnesota, New Jersey, or
Pennsylvania, and any town in the New England States, New York, or
Wisconsin, at least 90 percent of whose population is classified by
the Bureau of the Census as urban, provided it does not contain any
part of a dependent incorporated place.
Commuting Interchange--The commuting interchange between two
areas is the sum of the number of workers who live in either of the
areas but work in the other.
County--For purposes of the standards, the term ``county''
includes county equivalents, such as parishes in Louisiana and
boroughs and census areas (formerly census divisions) in Alaska.
Certain States contain cities that are independent of any county;
such independent cities in Maryland, Missouri, and Nevada are
treated as county equivalents for purposes of the standards.
In Virginia, where most incorporated places of more than 15,000
are independent of counties, the standards usually regard each such
city as included in the county from which it was originally formed,
or primarily formed. In certain exceptional cases, the city itself
is treated as a county equivalent, as follows:
(a) An independent city that has absorbed its parent county
(Chesapeake, Hampton, Newport News, Suffolk, Virginia Beach); and
(b) An independent city associated with an urbanized area other
than the one with which its parent county is primarily associated
(for example, Colonial Heights).
A county included in a metropolitan area is either a central
(section 2), or an outlying (section 3) county. An outlying county
must be contiguous with a central county or with an outlying county
that has already qualified for inclusion.
Employment/Residence Ratio--This ratio is computed by dividing
the number of persons working in the city by the number of resident
workers with place of work reported. (These items are taken from the
most recent national census.) For example, a city with an equal
number of jobs and working residents has an employment/residence
ratio of 1.00.
Interim Area--An area that meets the requirements of sections 1
through 4, or sections 11 through 13, for metropolitan statistical
area qualification, which needs to be further examined to determine:
(1) if it qualifies for combination with any adjacent interim area,
(2) its final level, based on population; and (3) if the area has 1
million or more population, the identification of primary
metropolitan statistical areas, if any, and the preferences,
expressed through local opinion, for consolidated or individual
identity.
Largest Central City--The largest central city of a metropolitan
area is the central city with the greatest population at the time of
the initial metropolitan area designation. Once determined, the
largest central city will not be replaced until both its population
and the number of persons working within its limits are exceeded by
those of another city in the area.
Outcommuting--The number (or percent) or workers living in a
specified area, such as a city or a county, whose place of work is
located outside that area.
Qualifier Urbanized Area--The qualifier urbanized area(s) for a
metropolitan statistical area are:
1. The urbanized area that resulted in qualification under
section 1B or the urbanized area containing the city that resulted
in qualification under section 1A.
2. Any other urbanized area whose largest city is located in the
same county as the largest city of the urbanized area identified in
paragraph one above, or has a least 50 percent of its population in
that county.
Secondary Noncontiguous Urbanized Area--An additional urbanized
area within a metropolitan statistical area that has no common
boundary of more than a mile with the main urbanized area around
which the metropolitan statistical area is defined.
Standard Metropolitan Statistical Area--The term used from 1959
to 1983 to describe the statistical system of metropolitan areas,
and the areas as individually defined. It was preceded by Standard
Metropolitan Area (SMA) from 1950 to 1959, and superseded by
Metropolitan Statistical Area in 1983. That term was adopted when
the current system formally recognizing consolidated metropolitan
statistical areas and their component primary metropolitan
statistical areas was put in place. The term Metropolitan Area (MA)
is used to describe the system and the areas collectively, but the
individual areas will retain the MSA, CMSA, and PMSA nomenclature.
Urban--The Bureau of the Census classifies as urban:
(a) The population living in urbanized areas; plus
(b) The population in other incorporated or census designated
places of at least 2,500 population at the most recent national
census.
Urbanized Area--An area defined by the Bureau of the Census
according to specific criteria, designed to include the densely
settled area around a large place. The definition is based primarily
on density rather than governmental unit boundaries. An urbanized
area must have a total population of at least 50,000. (See qualifier
urbanized area and secondary noncontiguous urbanized area).
Appendix B--OMB Memorandum M-94-22, ``Use of Metropolitan Area
Definitions''
May 5, 1994
M-94-22
MEMORANDUM FOR HEADS OF DEPARTMENTS AND AGENCIES
FROM: Leon E. Panetta
SUBJECT: Use of Metropolitan Area Definitions
On December 28, 1992, the Office of Management and Budget issued
revised metropolitan area (MA) definitions to reflect shifts in
population and other demographic changes that had occurred during
the preceding decade. At the time the revisions
[[Page 70561]]
were announced, we provided guidance (OMB Bulletin 93-05) to Federal
departments and agencies concerning the use of MA definitions for
statistical purposes.
During the past year, we have received a substantial number of
letters from Members of Congress, local government officials, and
others involved with administering various Federal programs. For the
most part, their correspondence has been related to nonstatistical
uses of the MA definitions in the allocation of Federal program
funds. Their concerns have highlighted the need to reiterate the
purposes for which OMB defines metropolitan areas and our advice
with respect to other uses agencies may make of these definitions.
The metropolitan area classification provides a nationally
consistent set of definitions suitable for collecting, tabulating,
and publishing Federal statistics. The definitions of metropolitan
areas are established and maintained solely for statistical
purposes. In periodically reviewing and revising the MA definitions,
OMB does not take into account or attempt to anticipate any
nonstatistical uses that may be made of the definitions, nor will
OMB modify the definitions to meet the requirements of any
nonstatistical program.
We recognize that some legislation specifies the use of
metropolitan areas for programmatic purposes, including allocating
Federal funds. For example, the Health Care Financing Administration
uses MAs to define labor market areas and gather hospital wage data
that are used in developing a hospital wage index for the labor
related portion of a hospital's standardized Medicare payment. The
Department of Housing and Urban Development's Community Development
Block Grant (CDBG) program targets 70 percent of CDBG funds to
``entitlement communities'' which include cities of 50,000 or more
or central cities of MAs. We will continue to work with the Congress
to clarify the foundations of the metropolitan area definitions and
the resultant, often unintended consequences of their use for
nonstatistical purposes.
In cases where there is no statutory requirement and an agency
elects to use the MA definitions in a nonstatistical program, it is
the sponsoring agency's responsibility to ensure that the
definitions are appropriate for such use. When an agency is
publishing for comment a proposed regulation that would use the MA
definitions for a nonstatistical purpose, the agency should seek
public comment on the proposed use of the MA definitions.
I would appreciate your sharing this information with others in
your department or agency.
Note: The latest version of OMB Bulletin 93-05, referenced
above, is OMB Bulletin No. 98-06, issued on June 23, 1998.
Appendix C--Summary of the Conference on New Approaches to Defining
Metropolitan and Nonmetropolitan Areas
This conference, held on November 29-30, 1995 in Bethesda,
Maryland, constituted part of the Office of Management and Budget's
metropolitan area standards review that is to be completed by spring
2000. The conference provided an open forum for discussion of
proposed alternative approaches to defining metropolitan and
nonmetropolitan areas, as well as discussion of the current
metropolitan area standards. Presentations of findings from four
commissioned studies of alternative approaches to defining areas
were the centerpiece of the conference. Papers from these studies
were published in Metropolitan and Nonmetropolitan Areas: New
Approaches to Geographical Definition, Population Division Working
Paper No. 12, Bureau of the Census.
Conference Points of General Agreement
The Federal Government should define standard
metropolitan and nonmetropolitan areas.
The metropolitan and nonmetropolitan areas defined
should cover the entire territory of the United States and better
account for the full range of settlement patterns than do the
current, dichotomous metropolitan areas and nonmetropolitan
residual.
Metropolitan and nonmetropolitan areas should be
defined according to the same set of rules for all parts of the
country.
A county-based set of metropolitan and nonmetropolitan
areas is necessary, but also there should be alternative, sub-county
unit-based areas.
Familiar components of settlement--including those
represented by today's metropolitan area definitions--should be in
evidence in a new system.
Conference Views on Major Questions
The conference explicitly addressed a list of major questions
that are fundamental to any set of areas defined by the Federal
Government. These same questions had been addressed in the
commissioned studies that were the centerpiece of the conference.
Presented here are summaries of the conference discussions of these
questions.
What should be the basic geographic units for defining areas?
There was strong consensus that there must be a county-based set of
defined areas for reasons of data availability, comparability, and
familiarity, but also there were comments favoring additional sets
of areas based on sub-county units for greater precision and special
purposes. There were suggestions that multiple sets of areas should
be provided, along with documentation on appropriate uses of those
sets. There also were suggestions that the Census Bureau and the
Office of Management and Budget should facilitate ``do-it-yourself''
definitions by making readily available as much small-area data as
possible.
What should be the criteria for aggregating the basic units?
Commuting data as obtained from the decennial census were regarded
as the best measure for defining areas by most individuals
addressing this question. Other data-including electronic media and
newspaper market penetration data, local traffic study data, and
wholesale distribution data-are available and usable for specific
purposes. Population and housing density data are useful for some
purposes within the definition task. Employment density also
received mention.
Should there be hierarchies or multiple sets of areas? As
already noted, there were comments favoring use of different
geographic units to define sets of areas that would be available for
different purposes. There also was discussion--without any clear
outcome--of classifying entities within a nationwide metropolitan/
nonmetropolitan definition framework into such categories as inner
city and suburban.
What kinds of areas should receive official recognition? Inner
city, suburban, and exurban all received mention as areas that
should be recognized within metropolitan and nonmetropolitan areas,
but this issue was not fully addressed.
Should a new system provide nationwide territorial coverage?
There was strong agreement that the areas defined should cover the
Nation's entire territory.
Should the definition process follow strictly statistical rules
or allow a role for local opinion? There were reservations regarding
the usefulness of local opinion in a program of standard statistical
areas, but the majority view expressed was that soliciting local
opinion can serve a useful purpose, particularly in providing room
for accommodation on some issues of local significance without
threatening the integrity of the national system. The incorporation
of local opinion, two individuals noted, should come early in the
definition process.
What should be the frequency of updating? There was little
discussion of this topic, as the frequency of updating depends
heavily on decisions concerning basic geographic units, criteria for
aggregation, and data availability.
Should the Federal Government define metropolitan and
nonmetropolitan areas? The overall view was strongly in favor of
metropolitan and nonmetropolitan areas being defined, although a few
individuals seemed to support the idea of ceasing the Federal
Government's activity in this arena altogether. Areas defined by the
Federal Government offer to a wide community of data users the
advantage of direct data comparability, i.e., data from different
sources for areas with the same boundaries. This advantage may rise
in importance in the face of programs shifting to states. There also
were those who argued in favor of a standard set of areas on the
grounds that such areas were useful for non-statistical program
administration. Others noted that the absence of a standard set of
areas probably would produce competing sets of areas from different
Federal agencies.
[FR Doc. 98-33676 Filed 12-18-98; 8:45 am]
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