Census Tract

Dataset

Description

A geographic unit used by the US Census Bureau for publishing census and other demographic/economic data. They are small, relatively permanent subdivisions of a county. Census tracts generally have a population between 1,200 and 8,000 people. The boundaries are chosen with the intention of being maintained over a long period of time to assist with the analysis of statistical trends.

Note: A related concept of tribal census tracts also exist within federally recognized American Indian reservations. Unlike census tracts, tribal census tracts can cross both state and county boundaries.

Sourcing

Census Tracts are assigned by the US Census Department. They change every ten years to coincide with a new census. The US Census Bureau tries to keep the population of a Census Tract to 4,000 people. If at the time of a new census the population of a Census Tract has reached or exceeded 8,000 people, it will be split up into multiple tracts.

ATTOM has a library of shape files that define the boundary of each Tract. We have used those shape files to analyze 150 million properties and establish which tract each property falls within. Unless you have a specific need for the shapefiles you can take advantage of ATTOM's geocoding to purchase the lookup table that matches properties to tracts.

Note: Because property lines are used as one of the criteria for defining a census block, a property should only fall within one tract.

Tables/Views

The following tables can be used to access census tract information. When delivering solutions to customers, some or all of the information found in these tables may be consolidated into one or more views.

DimTract

A register of US census tracts, including their size and location.

Rows: 74k
Columns: 21
Family: Boundary
Type: Area
Geography Type: 49

PropertyBoundaryMatch

The PropertyBoundaryMatch table can be used to:

• Identify the census tract for a specific property; and
• Get a list of the properties that fall within a census tract

Dimension Tables

The following dimension tables provide lookups for various codes contained in the tables/views used by this data element.

DimGeographyType: The complete list of geography types used as boundaries as well as the dimension table used to provide details about each boundary

Examples

Census Tract Population for a Property

The following example demonstrates how to identify the Census Tract for a property and then extract demographics data for that Tract

/*
 * Census Tract demographics for a specific property.
 * Demonstrates how to match properties to Census Tract data such as demographics
 */
SELECT 
	-- Property Details
	pa.[ATTOM ID],
	CONCAT(pa.SitusAddress,', ',pa.SitusCity,' ',pa.SitusState,' ',pa.SitusZip) AS Address,
    
    -- Tract Data
	dt.Label,
	dt.LandAreaSquareMiles,
    
	-- Demographic data
	cd.Population,
	cd.Households
	
From adw.PropertyAddresses pa										-- Addresses
Left Join adw.PropertyGeodata pg on pa.[ATTOM ID] = pg.[ATTOM ID] 	-- Geocodes
Left Join adw.DimTract dt on pg.CensusTract = dt.TractKey 			-- Tract
Left Join adw.CommunityDemographics cd on cd.GeographyTypeKey = 49 And pg.CensusTract = cd.GeographyKey -- Demographics

Where
	pa.[ATTOM ID] = 333588695		-- Specific Property

Product Articles (P-Articles)

All solution packs containing the Census Tract data element will include the following p-articles to help you understand and use the data: -

• Census Boundaries 101