This blog post takes a dive into Zillow’s proprietary home value estimate, the so-called “Zestimate.” For those unfamiliar with this metric, the “Zestimate” uses state- of- the-art statistical and machine learning models that can examine hundreds of data points for each individual home.” Further explanation, along with more detail about the Zestimate, can be found here. Zillow’s algorithms update home values nationally multiple times per week. They take into account location, square footage, on- and off-market data, and market trends.

While it is inarguable that the Zestimate for any one home may not accurately reflect a true market value for that home, the belief is that, in aggregate, it can be a very useful barometer of home value across a wide geographic area. In particular, we are looking at how the Zestimate has changed over the last 30 days in an effort to see where home values (according to Zillow’s algorithm) are rising quickly at the county and super district level. Note that “superdistricts” are defined as groupings of Census tracts that nest within counties.

We have utilized Zillow’s API to gather a random sample of over 400,000 of the reported 1.97 million Atlanta area homes with Zestimates to generate aggregations of this estimate at the county and superdistrict level. The choropleth map below shows 30-day changes in Zillow home value estimates across the region, with yellow corresponding to lower (“cooler”) increases in home values and red corresponding to higher (“hotter”) increases in home values.

Zillow Map

Findings: County Level

With the darkest shade on the map, DeKalb County is the clear leader in recent Zestimate increases, with a median 30-day increase of 2.6% over a total sample size of 41,264 homes. The county with the second-highest median 30-day Zestimate increase is Fayette County, with a median 30-day Zestimate increase of 2.1%.

The lowest median 30-day increases can be found in Clayton (median 1.5% increase), Douglas (median 1.4% increase), Rockdale (median 1.3% increase), and Henry (median 1.2% increase) Counties. Geographically, there is a clear trend of relatively sluggish 30-day median increases in  the southern portion of the metro Atlanta region, compared to the rest of the 11-county ARC Region.

Findings: Super District Level

When considering the more granular super district level, a few things stand out. Firstly, the Decatur and SW DeKalb super districts feature the highest median 30-day Zestimate increases at 3.4% each. Elsewhere in DeKalb County, the NE DeKalb, NW DeKalb, and Chamblee super districts also feature strong Zestimate growth over the past 30 days, with median increases of 3.1%, 3.1%, and 3.0% respectively.

Secondly, as with many other demographic variables, we can see a stark contrast between the super districts in south Fulton County and the northern portion of the county. In fact, no super district in south Fulton County features a median 30-day Zestimate increase above 1.5%, while the north and central Fulton County super districts of Buckhead, Sandy Springs, Roswell, and N Fulton each feature median 30-day increases greater than 2.1%.

Finally, the W Fayette super district is a clear geographic outlier in the map above, as is its neighbor E Fayette. As mentioned above, no super districts in south Fulton have a median 30-day Zestimate increase above 1.5%, but this also holds true for all other super districts in the southern portion of the region surrounding these Fayette County districts.

Overall, Zillow’s home value algorithm shows strong growth in residential property values across the region. As we head into the summer months, will DeKalb County keep up its upward trajectory of residential property values? Only time will tell!