The most effective strategy for merging identities in Adobe Experience Platform is to leverage theIdentity Mapto include all available identifiers. In XDM schemas, you can designate multiple fields as identities. By including Email, Mobile Number, and CRM ID as identities, the Identity Service can use any of these values to find and link fragments of a customer's profile.

Selecting only one primary identifier (as suggested in Options A and C) is a restrictive legacy approach. In a modern CDP architecture, "Identity Stitching" is dynamic. If a customer provides their Email in one session and their Mobile Number in another, and a third record (the CRM) contains both, theIdentity Graphlinks all three. This creates a multi-dimensional identity that allows for segmentation regardless of which ID is present in the incoming data stream.

Using all identifiers within an Identity Map ensures the highest possible "match rate" for audience segmentation. For instance, if you are activating an audience to a social media destination that requires an Email, but your latest interaction only captured a Mobile Number, the platform uses the Identity Graph to retrieve the associated Email from the unified profile. This cross-channel recognition is only possible when all identifiers are treated as part of the stitched identity web rather than prioritizing one at the expense of others.