Economic Boundaries

Economic boundaries are established by the US Census Bureau (USCB) and the Office of Management and Budget (OMB). Over 150 million US properties are grouped into 4 regions, 50 states, 3,200 counties, and 11 million census blocks.

Census Boundaries

USCB uses the commonly used political boundaries of State and County to break the US down into convenient areas to administer and report. Below the county level, the USCB defined boundaries for County Subdivisions, Places, Census Tracts, Census Block Groups, and Census Blocks. The following diagram provides an example of these boundaries.

Zip Code Tabulation Areas (ZCTA)

With zip codes being widely used across the US for many purposes, the USCB also defines Zip Code Tabulation Areas that aggregate Census Blocks in a way that approximates USPS's definitions for a zip code. The codes used to define a Zip Code Tabulation Area match those used for Zip Codes. If a Census Block fits entirely within a zip code, it is assigned to that Zip Code Tabulation Area. If a Census Block spans multiple zip codes it is assigned to the Zip Code Tabulation area that matches to a plurality of properties. e.g. if a Census Block has 10 properties and 7 are in zip code 12345, and 3 properties are in zip code 12346, then the Census Block is allocated to the Zip Code Tabulation area 12345.

This also allows Census Blocks to be approximated to postal cities using Zip Code Tabulation Areas for the Zip Codes that correspond to a postal city.

Census Regions

The US Census Bureau also aggregates States into Regions and Divisions (see below).

Core-Based Statistical Areas (CBSA)

The Office of Management and Budget (OMB) defines CBSAs, combining counties with a high degree of economic integration. The boundary of a CBSA is based on the boundaries of the individual counties. CBSAs are classified as being either:

• Metropolitan Statistical Areas (MSAs) - Consist of the county or counties (or equivalent entities) associated with at least one urbanized area of at least 50,000 population, plus adjacent counties having a high degree of social and economic integration with the core as measured through commuting ties.
• Micropolitan Statistical Areas (µSAs) - Consist of the county or counties (or equivalent entities) associated with at least one urban cluster of at least 10,000 but less than 50,000 population, plus adjacent counties having a high degree of social and economic integration with the core as measured through commuting ties.

Within ATTOM Cloud, the PropertyAddresses view (or PropertyFeature table) is used to establish the county for a property. The DimCounty table is used to establish the CBSA (if any) applicable to the county. The description of the CBSA defines which CBSAs are MSAs and which are µSAs (e.g. MONTGOMERY, AL METROPOLITAN STATISTICAL AREA).

Combined Statistical Area (CSA)

The Office of Management and Budget (OMB) also defines 172 Combined Statistical Areas (CSAs) that combine MSAs and µSAs that demonstrate economic or social linkages as measured by commute patterns having an employment interchange measure (EIM) of 15 or more.

Employment Interchange Measure: A measure of ties between two adjacent entities. It is the sum of the percentage of workers living in the smaller entity who work in the larger entity and the percentage of employment in the smaller entity that is accounted for by workers who reside in the larger entity.

Within ATTOM Cloud, the DimCounty table can also be used to establish the CSA (if any) to which a county belongs

Metropolitan Division

A county or group of counties (or equivalent entities) delineated within a larger metropolitan statistical area, provided that the larger metropolitan statistical area contains a single core with a population of at least 2.5 million and other criteria are met. A Metropolitan Division consists of one or more main/secondary counties that represent an employment center or centers, plus adjacent counties associated with the main/secondary county or counties through commuting ties. Not all metropolitan statistical areas will contain metropolitan divisions.

Qualified Opportunity Zones (QOZ)

An economically distressed community where new investments, under certain conditions, may be eligible for preferential tax treatment. Localities qualify as QOZs if they were nominated for that designation by a state, the District of Columbia, or a U.S. territory and that nomination was certified by the Secretary of the U.S. Treasury via his delegation of authority to the Internal Revenue Service (IRS). QOZs are defined as a collection of one or more Census Tracts based on 2000 Census Tract boundaries.