What is identity resolution?
Identity resolution is the process of connecting data from different devices, channels, and systems to the same person or household. It creates a unified view of the customer, so one person's actions aren't counted as several separate visitors.
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How identity resolution works
The process matches identifiers such as email addresses, phone numbers, login IDs, and cookie IDs. When two records share an identifier, they're linked to the same profile.
Deterministic matching uses exact identifiers like a login. Probabilistic matching estimates links from signals such as device and behavior, so it's less certain.
Why it matters
People use phones, laptops, and tablets, and they move between ads, sites, and stores. Without linking, you may count one person many times and miss the path that led to a sale.
Better matching improves audience building, personalization, and attribution.
Privacy and accuracy
Linking identities involves personal data, so it needs a lawful basis and clear disclosure. Wrong matches can merge different people, so check how your tool decides what counts as a match.
Common questions
What's the difference between deterministic and probabilistic matching?
Deterministic matching relies on exact shared identifiers, like an email. Probabilistic matching uses statistical signals to guess that records belong to the same person.
Is identity resolution the same as a CDP?
No. Identity resolution is a capability. A CDP is a platform that usually includes it, along with data collection and activation.
Why is identity resolution harder now?
Browsers limit third-party cookies and privacy rules limit data sharing, so there are fewer identifiers to link on.
How does first-party data help?
Identifiers people give you directly, like an email at sign-up, are reliable anchors for linking their activity across devices.
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