Appendix II
Metropolitan and Micropolitan Statistical Areas:
Concepts, Components, and Population
The United States Office of Management
and Budget (OMB) defines metropolitan
and micropolitan statistical areas accord-
ing to published standards that are ap-
plied to Census Bureau data. The general
concept of a metropolitan or micropolitan
statistical area is that of a core area con-
taining a substantial population nucleus,
together with adjacent communities hav-
ing a high degree of economic and social
integration with that core. Currently de-
fined metropolitan and micropolitan sta-
tistical areas are based on application of
2000 standards (which appeared in the
Federal Register on December 27, 2000)
to 2000 decennial census data. Current
metropolitan and micropolitan statistical
area definitions were announced by OMB
effective June 6, 2003.
Standard definitions of metropolitan
areas were first issued in 1949 by the
then Bureau of the Budget (predecessor
of OMB), under the designation ‘‘standard
metropolitan area’’ (SMA). The term was
changed to ‘‘standard metropolitan statis-
tical area’’ (SMSA) in 1959 and to ‘‘metro-
politan statistical area’’ (MSA) in 1983.
The term ‘‘metropolitan area’’ (MA) was
adopted in 1990 and referred collectively
to metropolitan statistical areas (MSAs),
consolidated metropolitan statistical areas
(CMSAs), and primary metropolitan statis-
tical areas (PMSAs). The term ‘‘core based
statistical area’’ (CBSA) became effective
in 2000 and refers collectively to metro-
politan and micropolitan statistical areas.
OMB has been responsible for the official
metropolitan areas since they were first
defined, except for the period 1977 to
1981, when they were the responsibility
of the Office of Federal Statistical Policy
and Standards, Department of Commerce.
The standards for defining metropolitan
areas were modified in 1958, 1971, 1975,
1980, 1990, and 2000.
Defining Metropolitan and Micropoli-
tan Statistical Areas—The 2000 stan-
dards provide that each CBSA must con-
tain at least 1 urban a