CHAS Data (Comprehensive Housing Affordability Strategy)

What Is CHAS Data?

CHAS data are a set of housing need estimates that HUD obtains every year from the U.S. Census Bureau. The name comes from the Comprehensive Housing Affordability Strategy, a planning document required under the Cranston-Gonzalez National Affordable Housing Act of 1990. That strategy was later folded into the Consolidated Plan.

The Census Bureau builds the tables from American Community Survey responses using categories HUD specifies. The main purpose, according to HUD, is to show the number of households that need housing assistance. These are households that have housing problems and incomes low enough to qualify for HUD programs.

How CHAS Data Work

CHAS sorts every household into “buckets” defined by several dimensions at once. The most important are:

• Income relative to HUD Area Median Family Income (HAMFI), in bands such as 30% or less, 30–50%, 50–80%, 80–100%, and above 100%
• Tenure, meaning renter or owner
• Household type, such as elderly, family, or a person with a disability
• Housing problems

HUD defines four housing problems:

1. The unit lacks complete kitchen facilities.
2. The unit lacks complete plumbing facilities.
3. The household is overcrowded, with more than one person per room.
4. The household is cost-burdened, paying more than 30% of income for housing, including utilities.

HUD also tracks severe overcrowding, meaning more than 1.5 persons per room, and severe cost burden, meaning housing costs above 50% of income.

The tables report counts, not percentages. To find, for example, the share of renters at or below 50% of HAMFI who are severely cost-burdened, users add up the right buckets and divide by the correct total. HUD offers a simple query tool, full downloadable files, an API, and its public mapping tool, CPD Maps.

Why It Matters for Workforce Housing

CHAS is one of the few public sources that cross-tabulates housing cost burden by income band for small geographies. That makes it a standard input for housing needs assessments and grant applications.

For workforce housing, the 80–100% band is especially useful. It can document cost burden among renters who earn just above the 80% limit that HUD programs commonly use.

Criticisms and Limitations

• Lag. Five-year ACS estimates average conditions over several years and are released well after the survey period ends.
• Margins of error. Estimates for small cities and towns can be imprecise.
• Suppression. Starting with the 2014–2018 tables, Census disclosure-avoidance rules have suppressed some categories, so comparisons with older years require care.
• Coarse top band. The standard five-band breakdown lumps together every household above 100% of HAMFI, which hides needs between 100% and 120% of HAMFI. Only some tables use finer income bands.