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The U.S. Department of Housing and Urban Development (HUD) has received from the U.S. Census Bureau a "special tabulation" of American Community Survey (ACS) data that are largely not available through standard Census products. These special tabulation data provide counts of the numbers of households that fit certain combinations of HUD-specified criteria such as housing needs, HUD-defined income limits (primarily 30, 50, and 80 percent of median income) and household types of particular interest to planners and policy-makers. These data, known as the Comprehensive Housing Affordability Strategy (CHAS) data, are used by local governments for housing planning as part of the Consolidated Planning process. HUD may also use some of these data in allocation formulas for distributing funds to local jurisdictions.
HUD released similar data after the 1990 and 2000 Census and made most of those data available to grantees and the general public. Those data can be accessed here: CHAS 2000. In 2005, the Census Bureau began full implementation of an annual survey called the American Community Survey, which will replace the detailed survey portion of the decennial census. The ACS will offer timely data for the period between censuses, allowing for a much more timely picture of local conditions. The transition from the Census long-form to the ACS also provided HUD an opportunity to revise the CHAS data. However, the sample of households surveyed each year through the ACS is smaller than the sample for prior decennial censuses. The new CHAS data reflects HUD's effort to adapt to these new data constraints, and to improve the usefulness of the CHAS data. These CHAS data are not directly comparable to the 1990 and 2000 CHAS, but generally the same housing problems, income categories, and household types were used. HUD intends to update the CHAS data regularly going forward, and will have frequent opportunities to improve the usefulness of the data. Comments and suggestions should be sent to Paul.A.Joice@hud.gov with "CHAS feedback" as the subject line.
DATA FORMAT
HUD has identified a large set of characteristics of interest to housing planners and policy-makers, and as a result the CHAS data can be quite unwieldy. To streamline the data and make it easier to use, HUD has created a series of tables, which are grouped by theme. More information about each of these tables, including a detailed data dictionary and a user's guide, is available here: CHAS resource page.
GEOGRAPHIES
Due to the small sample size of the ACS (relative to previous decennial census surveys), the Census Bureau cannot generate reliable data in a single year for geographic areas with populations under 60,000. As a result, data estimates are created from averages of 3 years and 5 years of survey responses. The Census Bureau summary level codes for the data currently available are:
040 = State
050 = State - County
060 = State - County - County Subdivision (MCD)
These are census definitions, which may be different than terminology used at the local level. For instance, St. Louis city and Baltimore city are treated as counties by the Census Bureau, and are geographically exclusive of their surrounding counties. Minor civil divisions are a census term for cities in certain states. MCDs are included their surrounding counties, but can be broken out separately. For instance, Chicago is a minor civil division within Cook County; the CHAS data for Cook County includes Chicago households, but Chicago's data can be separately viewed in the MCD files. In contrast, the city of Los Angeles is not a minor civil division so the only CHAS data currently available for Los Angeles is Los Angeles County. MCDs are the only cities for which HUD has obtained CHAS data at present. In 2010 HUD will obtain CHAS data for cities that exceed the 20,000 population threshold. In 2011, 5 year ACS data will be available, and HUD expects to obtain CHAS data for smaller cities and census tracts.
More explanation of Census geography is available here: Understanding Census Bureau Geography.
As with the CHAS 2000, rounding rules applied to all special tabulation data. This causes discrepancies when adding up smaller geographies. It has a similar effect when creating your own subtotals within a table. As a result, HUD recommends using the largest geographies possible, and the fewest number of table dimensions possible. In addition, the ACS can have very large margins of error, particularly with cross-tabulated data such as the CHAS. HUD realizes that some in some jurisdictions, for certain data elements, the ACS data may show unexpected results.
WAYS TO ACCESS THE DATA
The 2000 CHAS data were made available on the State of the Cities Data Systems Simple Query System. That platform has not yet been updated to be compatible with the new CHAS data. For the time being, users will have to download the data in one of several file formats. HUD received the data from the Census Bureau as a zipped set of SAS files and text files, which can be downloaded here (*.zip, 89.1MB). HUD also created a set of reformatted files, which are provided below in SPSS and Excel format. Those interested in analyzing data only for their locality should be well-served by the Excel data for their specific state, while those interested in analyzing data for the whole country may need to use the nationwide SPSS files.
Click here to download State CHAS data in SPSS format (*.zip, 2.0MB)
Click here to download State - County CHAS data in SPSS format (*.zip, 62.0MB)
Click here to download State - County - County Subdivision CHAS data in SPSS format (*.zip, 32.7MB)
Click here to download the State CHAS data in Excel format (*.zip, 4.0MB)
Click here to download CHAS data for a specific state in Excel format
UPDATES
