Core identity fields
First name, last name, middle name, gender, date of birth, and zone are taken from the priority customer — the profile that wins during deduplication. The values from the lower-priority profile are dropped for these fields, even if they look more complete. If you want a specific profile’s identity data to survive, make sure that profile is the priority customer before the merge runs.Additional (custom) fields
Custom fields also default to the priority customer’s values. There’s one important exception:If the lower-priority profile has a value in a custom field and the priority profile does not, the lower-priority value is carried over to the merged profile. Nothing is lost just because it lives on the non-priority side.
Action history
Actions from both customers are combined and kept on the final merged profile. This includes the full interaction history — orders, campaign opens, clicks, site events, subscriptions, and any other tracked actions from either profile. You end up with one consolidated timeline rather than two partial ones.Quick reference
| Data | Source after merge |
|---|---|
| First name, last name, middle name | Priority customer |
| Gender | Priority customer |
| Date of birth | Priority customer |
| Zone | Priority customer |
| Custom fields (priority profile has a value) | Priority customer |
| Custom fields (priority profile is empty, other profile has a value) | Other profile |
| Action history | Combined from both profiles |