FAQ - ATTOM Data

Does ATTOM Data use any proprietary algorithms or transformations in their data?

AVM is a logic based file that Attom has created based on the data they have collected. All other datasets are sourced from county assessor or recorder offices, third party vendors and partners.

Are there unique identifiers (e.g., property IDs, geocodes) that allow integration with external datasets?

APN and lat/long can be used to match to external datasets

How does ATTOM differ from or complement other real estate datasets?

The main differentiator is the ATTOM ID, which provides the ability to bring disparate datasets real estate datasets together to tell a more cohesive story.

Are there known biases or coverage issues?

ATTOM Data has coverage reports available in them additional resources section of the main partner page. At a high level:

• About 98% of US population
• 155m also includes commercial
• Does not include tax-exempt properties
• Rural properties may have less complete data, but it will still appear (e.g po boxes may be the same for multiple properties in the same area)

What property types does ATTOM Data cover?

In the data, there are two property type attributes

PROPERTYUSEGROUP - High-level property type (Residential, commercial, etc.)

property use standardized- More granular (townhome, condo, single family, etc.)

Where can I look up codes in the data?

See the Catalog of Elements in the resources section of the main data partner page.

What causes a parcel number to change?

A parcel number might change to something else primarily due to changes in the property itself, such as a land division (splitting the property into smaller parcels), a lot line adjustment, a property merger (combining multiple parcels into one), or even updates to the mapping system used by the assessor's office which might require renumbering for accuracy.

In the event of a parcel number change, the ATTOM ID will also change

Where can I look up the codes referenced in the different datasets?

ATTOM Data has provided a handful of external resources which can be used to map different codes. Those resources can be found in their supplementary files.