Should support for individual query parameters be mandated?

[Dunmail]

From Epic:

Asset

https://build.fhir.org/ig/HL7-UK/UK-Core-Access/clinical_data.html#allergyintolerance-search

This feedback applies across many (most?) of the UK Core profiles.

Comment

Overall, you should not mandate support of individual query parameters unless there's clearcut value for them.

Proposal

Rather, you should mandate search parameter combinations. For example, AllergyIntolerance?clinical-status is mandated, but AllergyIntolerance?patient&clinical-status is only recommended. The second search, combining patient and clinical-status is so much more useful than the first.

For an example of nuanced search parameter requirements, see IPA's Observation: https://hl7.org/fhir/uv/ipa/CapabilityStatement-ipa-server.html#Observation1-8