We focused on housing reports that try to capture the current value and recent changes to the value of homes within the Bay Area’s rental and real-estate markets. This review was originally intended for internal purposes, but we thought it was worth sharing more widely.
The Chronicle data team’s preferred data resources for understanding changes to home values are CoreLogic, Zillow and the U.S. Census American Community Survey (ACS). For changes to the rental market, we recommend Apartment List, Zillow and the ACS. But we also recognize that other data sources may be appropriate depending on exactly what a person is hoping to learn.
Where to find the data: https://tinyurl.com/2jbrfabj
What they aim to provide: Zillow offers detailed monthly data on how home values and rents are changing, ranging from nationwide trends down to shifts at the neighborhood level.
Instead of just looking at homes that have sold in a given month, Zillow calculates monthly changes to its “Zestimates” — estimated values for nearly every home in the U.S. It calculates a home’s Zestimate by looking at its features (the number of bedrooms, for example), location and sales of homes nearby, among other factors.
To look at changes to rents, Zillow uses what’s called a “repeated transaction” methodology, where it only looks at properties that have been listed more than once. This allows it to analyze changes to rents for the same units over time.
Strengths: Zillow is generally regarded as one of the country’s best sources for property value data because of the Zestimate, which allows it to track changes to values of all homes, not just properties that have recently been on the market. Because the Zestimate does not rely solely on recent sales data, its reports can also be produced more quickly than others and capture changes reliably down to the neighborhood level.
Weaknesses: Zillow’s index is not quite as accurate when estimating the average value of listed homes as, say, Redfin, whose index focuses more on currently listed properties than every home that exists. Zillow’s real estate and rental numbers also do not reveal as much about what is on the market, as they give a sense of overall price levels.
U.S. Census Bureau American Community Survey
Where to find the data: https://tinyurl.com/y7835c5x
What they aim to provide: The American Community Survey (ACS) gathers multiple data points on housing in the U.S. on a yearly basis, including the share of homes that are occupied by renters vs. homeowners, the self-reported values of those homes, and median rents.
Strengths: The ACS surveys over 3.5 million U.S. households and is generally regarded as one of the most accurate sources of data about the American population over time. Its data can assess changes to rents and home values down to the neighborhood level.
Weaknesses: The American Community Survey relies on self-reported data, and not everyone may report their own home values or rents accurately. The survey also only publishes once a year, so its data will not reflect monthly fluctuations in the housing market.
Rentals: Not for the Bay Area
Where to find the data: https://tinyurl.com/yuj55h3x
What they aim to provide: CoreLogic’s main product is the Case-Shiller Home Price Index, which reflects the average change in home values across 20 different metropolitan areas and is calculated monthly.
Strengths: The index is considered the gold standard for housing value data for people seeking to understand changes to the U.S. housing market over time; the Federal Housing Finance Agency uses it, as do many of the property websites listed below. It only uses data on houses that have sold at least twice to capture how each unit has changed in value over time.
Weaknesses: The Case-Shiller Price Index doesn’t update as quickly or frequently as some of the property data reports below. The Index also doesn’t have data at a level more granular than metropolitan areas, and only indexes a select number of metro areas (although San Francisco is included). Finally, its index does not list a dollar value for a typical home in a given region.
Where to find the data: https://tinyurl.com/7ufp8e2w
What they aim to provide: Redfin publishes data on monthly sales prices of homes, among other reports. It draws from sales reported to county governments and multiple listing services, organizations that gather home sales data from lots of realtors. It has also recently started to publish data on average monthly rents.
Strengths: Redfin publishes data more quickly than many other platforms, and provides both median sales price data and a Redfin estimate, which is similar to Zillow’s Zestimate in that it considers multiple aspects of a home including its location and other attributes. Unlike Zillow, however, Redfin focuses on homes that are currently on the market — though it does calculate estimates for off-market homes.
Weaknesses: Redfin’s data is not as accurate as Zillow’s when looking at unlisted homes. This means that if you’re using the site to understand the value of your own home before selling it, you should search for similar homes near yours that have recently sold — not your own property. Redfin also has less-thorough coverage of areas outside of major metros, though the company’s Bay Area data is among its most reliable and complete.
California Association of Realtors
Where to find the data: https://tinyurl.com/tj252dhh
What they aim to provide: The California Association of Realtors (CAR) releases monthly data on real estate trends in California, including the number of home sales, median sale price, number of active listings and more.
The organization also calculates a Housing Affordability Index on a quarterly basis; this index looks at the percentage of households in a given region that could afford a median-priced single-family home.
Strengths: CAR focuses exclusively on California, which can be useful to people looking at trends across the state and within its regions. Its reports also analyze changes to inventory and active listings, providing a bird’s eye view of market demand.
Weaknesses: CAR primarily analyzes median prices, and does not account for changes in available housing stock, so is not as useful for assessing trends. In other words, while this data can reveal whether the average cost of a house in a market has risen, it does not say much about whether the price of a similar 3-bedroom house in the market is going up or not.
Where to find the data: https://tinyurl.com/uaz3n7d8
What they aim to provide: Compass publishes monthly reports on home prices and real estate trends in major Bay Area markets, including San Francisco, Marin and Oakland-Berkeley.
Strengths: For sheer volume of reports, Compass can’t be beat. And the reports cover a lot of ground, citing everything from monthly new listings and average number of days on market to an “unsold inventory index,” which calculates how long it would take for all homes in a given market to sell out at the current rate of sales. Compass averages its sales data across three months to help control for outliers.
Weaknesses: Compass lacks its own sophisticated index like the Zestimate or the Redfin Estimate, and the company’s Bay Area reports do not generally incorporate Census data, which include a wider range of housing types, like public housing. So its reports might have a higher margin of error than Redfin and Zillow.
Where to find the data: https://tinyurl.com/88d25zaz
What they aim to provide: Apartment List publishes a monthly report that estimates median rent for studio apartments and 1, 2, 3 and 4+ bedroom apartments.
The company looks at data from the Census Bureau to analyze rent statistics for recent movers. Its analysts then estimate how rents have changed more recently using a growth rate calculated from listing data on its platform.
Strengths: Because Apartment List uses Census data and not just its own listings, its rent averages reflect more types of properties, including public housing and single-family rental homes. Other websites tend to over-represent more expensive rental units, according to Apartment List researcher Rob Warnock.
Apartment List also estimates changes in actual rents paid by renters, not list prices, which is helpful because landlords often reduce list prices over time as units remain vacant. Apartment List also uses a similar “repeat transaction” model as Case-Shiller and Zillow, where it looks at changes in the same apartments’ rents over time instead of just looking at how median rents overall have changed.
Weaknesses: While it uses Census data to look at median rents in various months, Apartment List only uses listings on its own platform to look at changes over time. So if rents change in a market segment that doesn’t have a strong presence on Apartment List, the platform may not accurately reflect changes to that market within a given month.
Where to find the data: https://tinyurl.com/7cpxvejj
What they aim to provide: Zumper generates monthly reports on changes to median rents for one- and two-bedroom apartments for the top 100 most populous cities in the U.S., plus hundreds of other cities within major metropolitan areas. Its most recent report for the S.F. Bay Area was published on August 26. It sources its rental data through its own website, as well as multiple listing services.
Zumper’s methodology excludes listings that are currently occupied or not on the market. Zumper spokesperson Crystal Chen said this allows the website’s reports to serve as “a better measure of what a consumer would experience shopping for an apartment at any given time.” Chen noted, however, that the site’s reports do not capture every new listing on the market.
Strengths: Zumper sources from over one million active listings per month, more than many other property websites, according to Chen.
Weaknesses: Like Compass, Zumper does not use an index to measure change over time — it looks at changes to median rents. Thus, its monthly data can look more volatile than the actual market, and potentially mislead consumers as to changes in a given market over time.
For instance, if a slew of new luxury apartment buildings were constructed within a year or two in Oakland, a report from Zumper might show that the median price of a one-bedroom apartment in the city jumped up, when in reality most of the city’s one-bedroom apartments could have hovered around the same monthly rental price.
Additionally, Zumper’s reports source largely from listings on its own website, which skew towards higher-income properties, according to urban economist Joe Cortwright. So median rents and home prices may look higher in Zumper reports than they actually are in reality.
Susie Neilson is a San Francisco Chronicle staff writer. Email: firstname.lastname@example.org Twitter: @susieneilson