Sources
Every number on Groundwork comes from one of the datasets below, and each panel names the source it draws on.
BLS Consumer Price Index (CPI-U)
Consumer price indexes, used to convert rents into constant dollars so a figure from 2018 can be compared with one from today. The San Francisco series are bimonthly, the national one monthly, and BLS publishes its own annual average once a year is settled, which we prefer to our own mean. The default index excludes shelter, because a shelter-inclusive index would measure rent partly against itself.
Updates monthly · Public domain; cite the Bureau of Labor Statistics.
BLS Local Area Unemployment Statistics
Employed residents by county, as an annual average. Counts working people who live in the county, not jobs located there. We use it as demand context beside housing production, because unlike DOF population estimates it is not derived from housing stock. It is context, not a measure of housing demand itself: people also leave a place because housing there is expensive. Note that the 2025 county averages cover eleven months, because BLS suspended October collection, so they are not strictly comparable with earlier years.
Updates annual · Public domain; cite the Bureau of Labor Statistics.
California DOF E-5 Population and Housing Estimates
Population and total housing units for every California city and county, as of January 1 each year. We use it for denominators (homes added per 1,000 existing homes, permits per 1,000 residents). Recent years come from DOF's E-5 report and years through 2020 from its E-8 report, which DOF has already reconciled to the 2020 census. We deliberately ignore the vacancy rate and occupied-unit columns, which are derived rather than measured.
Updates annual · California open data. City population is estimated with the Housing Unit Method, so it is partly derived from housing stock and is not an independent measure of demand.
Census Building Permits Survey
New privately-owned housing units authorized by building permits, by place. Survey-based with imputation; misses most ADUs and conversions. Loaded to cross-validate HCD APR permit counts, not as a panel source.
Updates monthly · Public domain; cite U.S. Census Bureau.
HCD Annual Progress Report
Jurisdiction-reported housing element progress: entitlements, building permits, and completions by income level, from annual reports due each April.
Updates annual · California open data. Self-reported by jurisdictions; HCD does not independently verify.
HCD RHNA Progress Report (6th cycle)
Each jurisdiction's 6th-cycle RHNA allocation by income band and cumulative building permits issued toward it. We derive prorated pace from these figures.
Updates annual · California open data. Progress is compiled from self-reported APRs and lags.
Zillow Home Value Index (ZHVI)
Smoothed, seasonally adjusted measure of the typical home value (35th-65th percentile band, all homes).
Updates monthly · Free with attribution on every page displaying the data; derivative charts allowed; no logos.
Zillow Observed Rent Index (ZORI)
Smoothed measure of the typical observed market-rate asking rent (repeat-rent index, mean of the 35th-65th percentile of listings, weighted to the full rental stock). The middle 30%, matching ZHVI's mid-tier cut.
Updates monthly · Free with attribution on every page displaying the data; derivative charts allowed; no logos.
How we turn these into charts is on the methodology page.