A method for an identity management system capable of being deployed incrementally, comprising: performing, by a biometric processing engine executing on at least one server, biometric matching between a first plurality of records from a first database and a second plurality of records from a second database, the first database and the second database comprising health-based databases established independently of each other, wherein each record from the first and second pluralities of records comprises a biometric record, and a corresponding identifier implemented to be unique across databases including the first and second databases; determining, by the biometric processing engine, that a first biometric record of a first record from the first database and a second biometric record of a second record from the second database, are from a same individual, the first record comprising a first unique identifier and the second record comprising a second unique identifier; maintaining, by a records arbitrator, in a poly-unique identity table, in which a given index uniquely refers to a single individual while more than one index number can refer to the same individual, on a storage device responsive to the determination, a link between the first unique identifier of the first record from the first database, and the second unique identifier of the second record from the second database; and providing, by the records arbitrator via one or more network interfaces to the first and second databases, in response to receiving a request identifying the first unique identifier or the second unique identifier, access to information about the individual linked to or stored with the first record of the first database, and information about the individual linked to or stored with the second record of the second database, according to the link maintained in the poly-unique identity table. performing, by a biometric processing engine executing on at least one server, biometric matching between a first plurality of records from a first database and a second plurality of records from a second database, the first database and the second database comprising health-based databases established independently of each other, wherein each record from the first and second pluralities of records comprises a biometric record, and a corresponding identifier implemented to be unique across databases including the first and second databases; determining, by the biometric processing engine, that a first biometric record of a first record from the first database and a second biometric record of a second record from the second database, are from a same individual, the first record comprising a first unique identifier and the second record comprising a second unique identifier; maintaining, by a records arbitrator, in a poly-unique identity table, in which a given index uniquely refers to a single individual while more than one index number can refer to the same individual, on a storage device responsive to the determination, a link between the first unique identifier of the first record from the first database, and the second unique identifier of the second record from the second database; and providing, by the records arbitrator via one or more network interfaces to the first and second databases, in response to receiving a request identifying the first unique identifier or the second unique identifier, access to information about the individual linked to or stored with the first record of the first database, and information about the individual linked to or stored with the second record of the second database, according to the link maintained in the poly-unique identity table.