VITAL SIGNS INDICATOR
Housing Affordability (EQ2)

FULL MEASURE NAME
Housing Affordability

LAST UPDATED
December 2022

DATA SOURCE
U.S. Census Bureau: Decennial Census - https://nhgis.org
Form STF3 – https://nhgis.org (1980-1990)
Form SF3a – https://nhgis.org (2000)

U.S. Census Bureau: American Community Survey - https://data.census.gov/
Form B25074 (2009-2021)
Form B25095 (2009-2021)

CONTACT INFORMATION
vitalsigns.info@bayareametro.gov

METHODOLOGY NOTES (across all datasets for this indicator)
The share of income brackets used for different Census and American Community Survey (ACS) forms vary over time. To allow for historical comparisons, the Census Bureau merges housing expenditure brackets into three consistent bins (less than 20 percent, 20 percent to 34 percent, and more than 35 percent) that work for all years. The highest income bracket for renters in the ACS data was \$100,000 or more, while the homeowner dataset included brackets for \$100,000 to \$149,999 and \$150,000 and above. These brackets were merged together to allow for uniform comparison across tenure. While some studies use 30 percent as the affordability threshold, Vital Signs uses 35 percent as this is the closest break point using the standardized affordability brackets above.

ACS 1-year data is used for larger geographies – Bay counties and most metropolitan area counties – while smaller geographies rely upon 5-year rolling average data due to their smaller sample sizes. Note that 2020 data uses the 5-year estimates because the ACS did not collect 1-year data for 2020.

Income breakdown data is only provided for one year as it is not possible to compare consistent inflation-adjusted income brackets over time given Census data limitations. For the county breakdown, Napa was missing ACS 1-Year renter data for all years except 2012 and 2013, and Marin was missing ACS 1-Year renter data for 2019 — these counties used 5-Year data for those years.