Market Data & Analysis
Get More (Better) Information on Housing Prices, Beyond What Zillow Shows You
Consumer portals are a starting point. Serious analysis uses a wider set of sources, and each one answers a different question.
By Rich Arzaga, CFP®, CCIM
The Real Estate Whisperer® Financial Planning
| 6 min read
Reliable housing price research requires going beyond consumer portals like Zillow and Redfin to professional-grade data sources: the FHFA House Price Index for long-term appreciation trends, Altos Research for real-time market dynamics, the U.S. Census Bureau for affordability and income context, and CoStar or Yardi for commercial and multifamily data. Each serves a different analytical purpose and answers different questions.
I was recently asked by a journalist to cite my sources for a comment on local housing market conditions. She seemed surprised when I listed several that were not Zillow. That is worth addressing directly, because the quality of your analysis is a function of the quality of your data sources, and consumer real estate portals are a starting point, not an ending point.
The problem with consumer portals
Zillow, Redfin, and Realtor.com are excellent for browsing listings, understanding list prices, and getting a rough sense of market activity. Their automated valuation estimates are useful ballparks but are known to have meaningful error rates, particularly in low-transaction markets and for unique properties.
They are also built primarily for buyers and sellers, not investors and analysts. They do not tell you cap rates, price-to-rent ratios, rent growth trends, or market-level supply and demand dynamics in the depth that serious investment analysis requires.
A Zestimate is a useful starting point. A professional data set is what you build investment decisions on.
Better sources for serious research
- FHFA House Price Index (hpi.fhfa.gov): definitive long-term price appreciation data by metro area and state, updated quarterly, free and authoritative
- Altos Research (altosresearch.com): real-time weekly data on days on market, price reduction rates, and inventory levels
- U.S. Census Bureau (census.gov): American Community Survey data on median household income, homeownership rates, and housing cost burden by geography
- CoStar and Yardi: professional-grade platforms for multifamily and commercial property, expensive but comprehensive, with limited access at many public libraries
The FHFA House Price Index is free, authoritative, and almost never cited in casual market discussions. That is a signal that most casual market commentary is missing the better data.
How to combine these sources
Start with consumer portals for listing-level research. Use FHFA for historical price appreciation context. Use Altos for real-time market dynamics. Use Census data for affordability and income context. And use CoStar or Yardi if you are analyzing multifamily or commercial acquisitions. Each answers a different question, and the combination gives you a complete picture.
Frequently Asked Questions
- Where can I find accurate housing price data?
- Beyond consumer portals like Zillow and Redfin, professional-grade sources include the FHFA House Price Index (free, quarterly historical data), Altos Research (real-time weekly market dynamics), the U.S. Census Bureau (affordability and income context), and CoStar or Yardi for multifamily and commercial data.
- How accurate is the Zillow Zestimate?
- Zillow's Zestimate is a useful starting point but has meaningful error rates, particularly in low-transaction markets and for unique properties. Zillow publicly discloses its median error rates by market, which can range from under 2% to over 7% depending on the area and data availability.
- What is the FHFA House Price Index?
- The Federal Housing Finance Agency House Price Index tracks changes in single-family home prices across the U.S., by state and metro area, going back decades. It is updated quarterly, freely available at hpi.fhfa.gov, and widely considered the most authoritative source for long-term price appreciation data.
- What data does Altos Research provide?
- Altos Research provides real-time weekly housing market data including active inventory levels, median list prices, days on market, price reduction rates, and market heat scores. It is used by real estate professionals who need current market dynamics rather than data that lags by months.
About Rich Arzaga, CFP®, CCIM
Rich Arzaga is the founder of The Real Estate Whisperer® Financial Planning and creator of The Real Estate Income Lab® and The 5% Real Estate Performance Gap®. He provides comprehensive, flat-fee financial advice that brings investment real estate together with retirement, investments, taxes, insurance, estate planning and the rest of a client's financial life.
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