Zillow vs. Reality: How accurate are Tri-Cities Zestimates®?

Introduction: Zillow vs Reality

For five months this year, we compared the Zestimate® of homes sold across the Tri-Cities with their actual sales price. What follows is a full report and recap of our data. In this study, you’ll learn that:

• The Zestimate® of a typical Tri-Cities home is almost 6 percent higher than the home’s actual sales price.
• Pasco has the most accurate Zestimates® in the Tri-Cities.
• Tri-Cities’ Zestimates® are more than twice as inaccurate as Zestimates® across the state.
• The more expensive a Tri-Cities home is, the more inaccurate its Zestimate® is.

How Zillow’s Zestimates® Work

Zillow’s “Zestimate®” is a computer-generated estimate of a home’s value. Zillow’s algorithm relies on all the available data it can find about a home, from sources that include public tax records, information from multiple listing services and real estate brokerages. It also accounts for a home’s “facts and features,” like the size and location of the home, and how many bathrooms it has. Zillow’s algorithm also incorporates the local real estate market — recent sales of comparable homes and how long homes are on the market.

When Zillow launched in 2006, the company says it had a median error rate of 13.6 percent — meaning half of all Zestimates® were within 13.6 percent of a home’s final sale price. That number has improved over the years. In January 2019, when Zillow announced the winners of a competition where programmers sought to improve the algorithm, the company said its median error rate was 4.5 percent. (Meaning half of all Zestimates® were within 4.5 percent of the actual sales price.)

Studying Zillow’s Accuracy

Zillow itself tracks the accuracy of Zestimates® across the U.S. and publishes the data on its website. The tracker focuses on 30 “top metro areas” — Seattle and Portland are included, but mid-sized markets like Spokane aren’t. And that means a smaller market like the Tri-Cities is missing, too.

With that in mind, early this year we began to study the accuracy of Zestimates® for Tri-Cities homes. On a nightly basis, we charted the home sales that closed that day and recorded both the actual sale price and the Zestimate® as published on Zillow. (Here’s a full look at our methodology.) Our goal was to educate ourselves and local home buyers/sellers about the accuracy of Zestimates® in the Tri-Cities. The more we understand about Zestimates® and real home values, the better we can serve our clients.

The results of our study are presented here. We’re reporting the data for the Tri-Cities area overall, as well as for each individual city tracked. You’ll also find data comparing Zestimate® accuracy with the price of homes. If you only have time to read one page, see the “Key Takeaways” link below for a summary.

Navigation

At the bottom of each page, you’ll find this list of pages that can be visited in whatever order you like.

1. Zillow vs Reality: Introduction (this page)
2. Zillow vs. Reality: Key Takeaways
3. Zillow vs. Reality: All Tri-Cities Zestimates®
4. Zillow vs. Reality: Kennewick Zestimates®
5. Zillow vs. Reality: Pasco Zestimates®
6. Zillow vs. Reality: Richland Zestimates®
7. Zillow vs. Reality: West Richland Zestimates®
8. Zillow vs. Reality: Home Value Comparisons
9. Our Methodology