How It Works
Price-to-Income Ratio: The total cost of a 30-year mortgage (principal + interest) divided by annual earnings. A higher ratio means housing is less affordable.
Data Sources
- Earnings: BLS Average Weekly Earnings, Total Private (CES0500000011)
- Home Prices: Zillow Home Value Index via FRED (USAUCSFRCONDOSMSAMID)
- Mortgage Rates: Freddie Mac 30-Year Fixed Rate via FRED (MORTGAGE30US)
Dual Income: Estimated at 1.4× single-earner income, reflecting typical dual-income household dynamics.
State-Level Data: When a state is selected, home prices reflect that state's Zillow Home Value Index (ZHVI) data sourced from FRED. Income is estimated by applying a state-specific multiplier to the national BLS average weekly earnings. This multiplier is derived from the BLS Quarterly Census of Employment and Wages (QCEW), comparing each state's private sector average weekly wage to the national average. Mortgage rates remain national regardless of state selection, using the Freddie Mac 30-year fixed rate.
Multiplier Availability: When QCEW data is unavailable for a given year, the state income multiplier falls back to 1.0 (equivalent to national earnings). Each state's JSON records the source as qcew_<year>, fallback_missing, or fallback_unavailable so the provenance of the income figure is traceable.
Data Annotations: Each weekly data point is categorized as one of three types. Observed points combine an exact Freddie Mac mortgage-rate Thursday with home-price and income series within their measured ranges. Interpolated points sit between real monthly observations and use linear interpolation for the missing weeks. Extrapolated points extend recent trends forward when source data has not yet been published. The per-state JSON surfaces these counts under metadata.series_quality.