A person may have more than one assigned identifier, but only one identifier per individual should be used within the agency recordkeeping system.

If agents are being linked to actions on records, this subelement and/or subelement M18 Personal Name can be used to facilitate the linking of agent details to actions on records recorded in element M66 MANAGEMENT HISTORY and, where used, elements M71 USE HISTORY and M76 PRESERVATION HISTORY.

Further identifiers may need to be added at a later time to uniquely identify the individual if records are moved outside the agency domain. In many cases, the addition of subelement M15 Corporate ID may be enough to uniquely identify an individual outside the agency domain.