Sailpoint correlation is the concept or logic to correlate the accounts of different applications through account aggregation to the already existing identities data in the Identity warehouse.
As we know all Identities exist in Sailpoint Identity Warehouse. all this Identity data came from some Authoritative source application.
Whenever we onboard any application, we usually run account aggregation and group aggregation for that application, so that we can pull account information and their entitlement information and persist in the Sailpoint.
During the account aggregation run, we need to check whether identities coming from the Application have already been present in SailPoint or not. means whether an identity account is already created or not.
If there is already identity is created then we will merge the identity data coming from account aggregation with the identity already created in Sailpoint through the Sailpoint IIQ correlation rule. if we don’t do correlation then duplicate identities will be created in the Sailpoint.