In an environment where an openEHR EHR server is deployed, there is often an
existing demographics service of some kind, such as a Patient Master Index.
However, the EHR needs to identify not just the patient, but also provider
organisations and individuals. Currently openEHR uses the PARTY_REF and
OBJECT_ID approach to do this in the ENTRY.provider and ENTRY.
other_participations attributes, but this assumes that the relevant
parties will be represented in the demographic service.
A problem occurs if there is no demographic data for the referenced
party beyond human readable and computable ids (e.g. "Wesley Hospital"
and "HIC provider number 123456789"), even though there is an openEHR
demographic service. The EHR still needs to have references to these
real world entities, even though they are not represented in the
A second scenario is where patient relatives need to be referred to in
ENTRY.subject (of type RELATED_PARTY), but only with informal identifiers
such as "uncle george"; also no other demographic information for such
people will be in the PMI anyway (i.e. only registered patients are there).
Another place in the model where PARTY_REF is used is AUDIT_DETAILS,
as the type of the committer attribute. The problem here is that it
implies that all EHR system users have some kind of entry in a
demographic system, which will clearly not be the general case. They
may have an entry in an identity service, or just a simple