What is Identity Resolution?
Identity resolution is the work of deciding which records in different data sets refer to the same person or household, so that a customer can be recognized across systems.
Why does Identity Resolution matter for marketers?
Every audience, measurement and personalization system depends on knowing that two records are one person. Doing it badly splits customers or merges strangers.
Where does Identity Resolution stand today?
Methods are either deterministic, matching on identifiers that must agree, or probabilistic, weighing evidence from several fields. Vendors sell identity products, for example LiveRamp's RampID and The Trade Desk's Unified ID 2.0, launched in mid-2020. Google decided in July 2024 to keep third-party cookies in Chrome, but consent rules still limit what can be linked.
Common use cases
- Merging duplicate customer records
- Recognizing customers across devices and channels
- Matching audiences between partners
The general problem is known as record linkage: finding records in a data set that refer to the same entity across different data sources, particularly where common identifiers are absent or inconsistent. In marketing it has long been called merge/purge or list washing, used to remove duplicate customer records and improve data quality.
Privacy-preserving approaches
Because organizations increasingly need to link data across entities, researchers have developed privacy-preserving record linkage, which encodes or encrypts values so that matching can happen without sharing the underlying plain-text data. Human review is still important for uncertain matches before results flow into other analyses.
Why it appears in this directory
Customer data platforms, clean rooms and advertising identity standards all rest on some form of identity resolution; see the related guides.