The U.S. Office of Management and Budget's (OMB's) designations of metropolitan areas—officially called "core-based statistical areas" (CBSAs)—can attract congressional attention in part because they can be important to congressional constituents. OMB observed in 2000 that CBSAs "represent areas in which people reside, work and spend their lives and to which they attach a considerable amount of pride." CBSA designations also can influence, as examples, public planning and decisions by businesses about where to locate or how to identify their markets. Thus, variables like the territory encompassed in an area, the territory excluded, and the area's title can generate interest among diverse constituents, including state and local officials, business groups, and nonprofit organizations. This interest can be heightened insofar as the standards are used in a particular way unintended by OMB, in formulas for allocating certain federal grant program funds. When the nationally uniform criteria, or "standards," for designating metropolitan areas are revised, state and local officials, among other constituents, may prompt their Members of Congress to ask how the changes might affect the federal funds distributed to their jurisdictions on the basis of these programs. This report presents a short history of metropolitan area standards, notes OMB's announcement of the standards for delineating these areas in the decade 2010 to 2020 (the 2010 standards) and the 2013 release of lists showing the actual CBSA delineations, gives details about the 2010 standards, and discusses the difficulty of ascertaining how metropolitan area designations affect federal funds allocation. Standards for designating metropolitan areas represent an attempt to describe systematically the linkage between a large population concentration and the territory surrounding it. According to OMB, the standards originated because of the realization, during the 1940s, that "the value of metropolitan data produced by Federal agencies would be greatly enhanced if agencies used a single set of geographic delineations for the Nation's largest centers of population and activity." At the time, agencies were designating "a variety of statistical geographic areas at the metropolitan level ... using different criteria applied to different geographic units." The result was that "one agency's statistics were not directly comparable with another agency's statistics for any given area." The U.S. Bureau of the Budget, predecessor to the Office of Management and Budget, "led the effort to develop what were then called 'standard metropolitan areas' in time for their use in 1950 census publications. Since then, comparable data products for metropolitan areas have been available." The first such areas were designated in 1949. The standards were revised in 1958, 1971, 1975, 1980, 1990, and 2000, as well as in 2010. The Bureau of the Budget became OMB in 1970. Responsibility for the standards passed to OMB, where it has remained except from 1977 to 1981, when it rested with the Office of Federal Statistical Policy and Standards in the U.S. Department of Commerce. Since the start of the metropolitan areas program, the standards for designating these areas have been reviewed "and, if warranted, revised ... in the years preceding their application to new decennial census data." Examination of the standards for 2000 to 2010 (the 2000 standards), to determine what, if any, revisions of them should occur before the 2010 census, began in 2008, when OMB "charged the Metropolitan and Micropolitan Statistical Area Standards Review Committee" with this task. The Commerce Department's Bureau of the Census (Census Bureau), which, among its other responsibilities as the nation's foremost statistical agency, conducts the decennial census, chaired the committee and "provided research support." Other representatives from the federal statistical system were the Bureau of Economic Analysis (in the Commerce Department), the Bureau of Labor Statistics (in the U.S. Department of Labor), the Bureau of Transportation Statistics (in the U.S. Department of Transportation, DOT), the Economic Research Service (in the U.S. Department of Agriculture, USDA), and the National Center for Health Statistics (in the U.S. Department of Health and Human Services, HHS). OMB was represented ex officio . The committee's recommendations for limited revisions of the standards were made public in 2009 and adopted by OMB in 2010, as discussed below. In a June 28, 2010, Federal Register notice, OMB announced the standards for delineating core-based statistical areas—the two categories of which are metropolitan and micropolitan statistical areas—during the decade 2010 to 2020. The terms "core-based statistical area" and "micropolitan" first were used in the 2000 standards. As OMB explained, the "general concept of a metropolitan statistical area is that of an area containing a large population nucleus [core] and adjacent communities that have a high degree of integration with that nucleus. The concept of a micropolitan statistical area closely parallels that of the metropolitan statistical area, but a micropolitan statistical area features a smaller nucleus." The Federal Register notice also presented the 2010 standards for delineating New England city and town areas (NECTAs), which are conceptually similar to CBSAs. The new standards, superseding those for 2000 to 2010, differ only slightly from the previous decade's and incorporate the changes recommended by the Metropolitan and Micropolitan Statistical Area Standards Review Committee. One recommendation was that OMB characterize the 2010 standards as being used to "delineate" rather than, as in the past, "define" the "boundaries or geographic makeup of an area." OMB accepted the change because, in its words, the term "define" was not "intuitive" to those unfamiliar with the metropolitan areas program and "occasionally ... caused misunderstandings." Other changes are noted below, in the detailed discussion of the 2010 standards. Although OMB declared the notice "effective immediately," it did not issue lists showing the actual delineations of CBSAs under the 2010 standards—the titles of the areas, together with their principal city and county components—until February 28, 2013. Newly delineated NECTAs and their components were issued then, too. Producing these lists involved applying the 2010 standards to population data from the 2010 census, as well as employment and commuting data from the Bureau's American Community Survey (ACS) estimates for 2006 through 2010. Hence, although OMB establishes the criteria for designating metropolitan areas, Census Bureau data are used to generate the specific areas. A core-based statistical area is a "statistical geographic entity consisting of the county or counties associated with at least one core (urbanized area or urban cluster) of at least 10,000 population, plus adjacent counties having a high degree of social and economic integration with the core as measured through commuting ties with the counties containing the core." CBSAs comprise whole counties and county equivalents in the United States and Puerto Rico. Counties that do not qualify to be in CBSAs are classified as "outside core-based statistical areas." OMB's inclusion of standards for delineating New England city and town areas acknowledged the particular importance of these jurisdictions to this six-state census division. NECTAs, which are not county based, are intended to be used, "whenever feasible and appropriate," with data for New England. OMB recommended, however, that those who need areas delineated according to nationally consistent geographic components—counties—choose CBSAs in New England. Each CBSA must contain "a Census Bureau delineated urbanized area of at least 50,000 population or a Census Bureau delineated urban cluster of at least 10,000 population." Urbanized areas and urban clusters collectively are called "urban areas." CBSAs are categorized as "metropolitan" or "micropolitan" according to the criteria below. Metropolitan statistical areas have urbanized areas of 50,000 or more people. Micropolitan statistical areas have urban clusters of at least 10,000 but fewer than 50,000 people. They represent a recognition that certain entities, although less populous than metropolitan statistical areas, have some characteristics in common with them and are not well described simply as "nonmetropolitan." New England city and town areas, like CBSAs, contain either urbanized areas or urban clusters and are called either "metropolitan" or "micropolitan." CBSAs have one or more principal cities, which include the most populous incorporated place in the CBSA with a 2010 census population of at least 10,000 people, or, if the CBSA contains no such place, the most populous incorporated place or census designated place (CDP); any additional incorporated place or CDP with a 2010 census population of at least 250,000 people, or where 100,000 or more people work; any additional incorporated place or CDP with a 2010 census population of at least 50,000 but fewer than 250,000 people, "in which the number of workers working in the place meets or exceeds the number of workers living in the place"; and any additional incorporated place or CDP with a 2010 census population of at least 10,000 but fewer than 50,000 people, which also has at least one-third the population size of the CBSA's most populous place, and where "the number of workers working in the place meets or exceeds the number of workers living in the place." The same criteria are used to designate the principal cities of NECTAs. CBSAs have one or more central counties. A central county receives this designation under either of the following conditions: at least 50% of the residents live in urban areas of 10,000 or more people; or the county boundaries contain a population of at least 5,000 people, located in a single urban area of 10,000 or more people. To qualify as an outlying county of a CBSA, a county must meet either of two criteria, both of which concern commuting to and from work: at least 25% of the outlying county's employed residents work in the central county or counties of the CBSA; or workers who live in the central county or counties of the CBSA account for at least 25% of the employment in the outlying county.