How does merging and matching work in SAP Marketing Cloud?

Matching logic works against existing records and against simultaneously imported data.

The number of best records can be configured for each contact.

The full name is used as an additional criterion to achieve a sufficiently high level of confidence to perform a soft match.

The "One Per Contact" configuration setting is used as a hard match criteria with a high level of confidence.

The date of birth is used as an additional criterion to achieve a sufficiently high level of confidence to perform a soft match