This feature allows a Site Administrator to add a Program-specific Custom Attribute created in another Program to the Program they’re currently in.
Simply choose from the list of attributes and click "Add this Custom Attribute". Click "OK" on the prompt: "Are you sure you want to add this Custom Attribute to your Program?"
Note: The added Attribute is not linked to the original Attribute with the same name; data entered in those two (or more) Attributes will not aggregate in reports.