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It may be a stretch to call it the Holy Grail of property data, but the quest to establish a “definitive” standard that creates one unique identifier for every property has been a challenge for decades. Many organizations have built their own proprietary ID systems but organizing a free, open ID system available to anyone has always been the goal.

Mark Bessett, Senior Enterprise Software/Data Architect for California Regional MLS (CRMLS), has been Chair of the RESO Universal Property Identification (UPI) Workgroup for the last four years. He knows the challenges all too well. How does one address all of the quirks of US real estate — which includes accounting for unique real property transactions that span from air rights to parking spaces, across state, county, and municipalities’ government agencies?

Tapping the brilliant minds from leading firms such as CRMLS, FBS, CRS Data, CoreLogic, Zillow Group’s Bridge Interactive, Cherre, and others produced a breakthrough property ID standard. The UPI Workgroup created a new identifier, comprising alphanumeric digits and hyphens, with components that identify the property’s attributes. The UPI is available under a public use license, with no licensing costs of any kind. And now, UPI adoption is gaining momentum that could shape it into the first meaningful definitive property identification standard.

Reaching a tipping point

Adoption of the RESO UPI standards has been progressing, but mostly on the data consumption side — firms that consume public data. For example, Bessett’s CRMLS, like many other large MLSs, are using the UPI within the RESO Data Dictionary.

Innovators are keen to use the UPI. Austin-based real estate brokerage Jovio builds proprietary products to streamline brokerage services. When acquiring data from multiple providers, the company generates UPIs via the RESO standard, eliminating property data duplication.

Bessett has watched the momentum build, but what’s needed for “this plant to grow” is adoption and implementation by major data records firms which provide the rich data to so many companies employ. That, he says, will make the UPI more useful and powerful.

“Where the rubber meets the road,” when it comes to the ultimate success of the UPI, “is when more data aggregators adopt the new standard,” he said, adding, “It’s great that an MLS or other firm is ready with the UPI to consume the data, but it can’t grow until you can create demand. Data record firms can create demand.”

The good news is that some data provider startups, such as Data Nerds, “are building the RESO UPI standard into everything,” Bessett notes.

Today, Bessett has more good news to share: Two of the biggest pillars in the data world — Zillow Group and CoreLogic — are throwing their support behind the UPI. Bessett believes the RESO-created UPI standard is at a tipping point.

Public records data provider CRS Data, led by Matt Casey, was an early UPI adopter and advocate along with a team from Zillow Group’s Bridge Interactive. Zillow Group is currently using the UPI widely, and data giant CoreLogic, which has been a crucial contributor to its development, is currently working with the UPI in its dataset.

Other major data aggregators, such as WolfNet, are planning to use the UPI in the future. All of this support should begin to create the demand Bessett says is needed for the UPI to flourish.

What’s special about UPI, and why use it?

A Universal Property Identifier’s benefits are broad and deep. The UPI practice eliminates duplicates of the same parcel, provides for easier identification of parcels across market boundaries, allows for the unification of public records from multiple sources in one display, and can deliver faster updates to physical property characteristics.

The UPI begins with a country code (creators wanted the UPI to be available for global use), a sub-country code (five-digits: a two-digit state code and three-digit county code), a sub-county code (where county subordinate entities maintain parcel numbers), a local property identifier (based on tax roll parcel numbers), the property type (i.e., real property, co-ops/apartment, commercial unit, etc.), and the sub-property identifier (optional, to account for lot, unit numbers or building designations).

Bessett offers a plant analogy to explain the UPI. “Think of a single property listing as a leaf. With a UPI, I could find the tree the leaf came from, and if I find the tree, I can find all the other leaves.”

In the case of the RESO UPI standard, it connects each property to many facts — potentially all the public data records for that listing. Once you have the UPI, you can then find out what data is available for that property listing. “Suddenly, I can have information that’s available from multiple vendors,” he says.

Bessett explains that, potentially, data not related to the transaction of the property could also be discovered through the UPI — insurance claims, city permits for property improvement, crime statistics, local demographics, affiliated school districts, prior loan history, and more.

The UPI will benefit both local data providers with a wealth of hyperlocal information and national data aggregators, in addition to the firms that consume the data. “The UPI vastly enriches the property’s listing,” Bessett says, which will benefit consumers, too.

Next up: UPI Registry

Because of the traction Bessett sees in the adoption and implementation of the UPI standard, the next logical step is to create a UPI Registry. The RESO UPI Workgroup has already put some work behind this effort, including the creation of a UPI Registry White Paper.

What the UPI does not do, Bessett clarifies with emphasis, is provide the actual data. The UPI is the key while the Registry is the “list.”

“It tells you what data is available and who has it,” says Bessett, explaining that data aggregators are not giving away their data, just acknowledging what data related to that unique property is available.

The UPI Registry is a way for organizations to contribute information associated with a UPI and register it as a fact. When an MLS has a property for sale, for example, the MLS could register that as a fact or event, but not include the listing itself

Here’s how it might work in practice: If Zillow registers public-facing website links, Zillow would have the ability to see real data on the resolving URL by accessing the UPI Registry. This is akin to what search engines do to derive relevance scores for each of the search results they deliver, based on references or links in other pages.

The UPI Registry helps a user validate the UPI. Without a registry, Bessett asks, “How do I know if it is a real UPI? It looks like one. It smells like one. But is it a UPI?” Going to the registry, Bessett explains, allows someone to validate the UPI. “If the registry says there are 1,000 pieces of information registered with that property, it’s probably a real UPI, and as a consumer of the data, that is very helpful,” he said.

Finally, Bessett emphasizes that no one’s data is stored on the Registry, and users only receive a link — nothing more. “Getting data is between the data consumer and the data provider and the terms of their data licensing agreement,” he explained, adding, “So the UPI Registry is something everyone should be able to support because ultimately it benefits the consumer. And anything that helps the consumer should be good for us.”

To learn more about the RESO UPI standard, you can download the specifications here, and find more information about the RESO UPI Workgroup online at Don’t miss the next in-person workgroup meeting at the RESO Fall Conference, “Data Standards: The Gateway to Home Run Technology Solutions.” Early bird registration is now open for the September 9-12 event at the Hilton St. Louis at the Ballpark with details at


Sam DeBord is the CEO of Real Estate Standards Organization, or RESO, the organization responsible for the creation, promotion, adoption, and utilization of standards to drive efficiency throughout the real estate industry.

DLU June 11th, 2019