Combined statistical area
Combined statistical area (CSA) is a United States Office of Management and Budget (OMB) term for a combination of adjacent metropolitan (MSA) and micropolitan statistical areas (μSA) across the 50 U.S. states and the territory of Puerto Rico that can demonstrate economic or social linkage. CSAs were first designated in 2003.[1][2] OMB defines a CSA by various combinations of adjacent metropolitan and micropolitan areas with economic ties measured by commuting patterns. CSAs retain their own designations as metropolitan or micropolitan statistical areas in their respective larger combined statistical areas.
For a list of all U.S. metropolitan areas, see List of primary statistical areas of the United States; this article only includes those metropolitan areas which the census bureau defines as a combined statistical area.
The primary distinguishing factor between a CSA and an MSA/μSA is that the social and economic ties between the individual MSAs/μSAs within a CSA are at lower levels than between the counties within an MSA.[3] CSAs represent multiple metropolitan or micropolitan areas that have an employment interchange of at least 15% (% commuting from A to B plus % commuting from B to A).[3] CSAs often represent regions with overlapping labor and media markets.
As of 2023, there are 181 combined statistical areas across the United States, plus another three in the territory of Puerto Rico.[3]