New blog & whitepaper: From “Must Support” to measurable interoperability with FHIR Obligations

Interoperability isn’t failing because we lack standards. It’s failing in the gap between “FHIR compliant” on paper and systems that actually work together in practice. One of the culprits has been the ambiguity of Must Support: everyone agrees an element “matters,” but nobody encodes what systems are really expected to do with it.

In a new blog post on our website, “From ‘Must Support’ to Measurable Interoperability: Why FHIR Obligations Are a Necessary Next Step,” I explain how FHIR Obligations take that implicit intent and make it explicit, actor-specific, and machine-readable—right inside the ‎⁠StructureDefinition⁠. Instead of hiding behavioral rules in narrative, profile authors can now:

• Define what behavior is required (e.g. SHALL populate, SHOULD display)
• Scope it to specific actors (producers, consumers, servers, clients)
• Add conditions and workflow context via FHIRPath and process links

The blog also clarifies how Obligations and Must Support work together rather than compete. Best practice is that any element with an Obligation is also marked Must Support, keeping profiles both future‑proof (behavioral testing, clearer conformance) and backward‑compatible with tools that don’t yet understand Obligations.

For architects, spec authors, and national programs that need interoperability they can measure instead of just assume, this is a meaningful shift: from narrative expectations to testable behavior.

Adding the Obligation extension (1) in Forge to an element that was already marked as Must Support (2)

If you want to dive deeper into the rationale, structure, and real‑world adoption, my new whitepaper, “Refining Conformance: An Analysis of the Evolution from Must Support to FHIR Obligations,” is now available as well. The paper walks through:

• The historical ambiguity of Must Support and its impact on implementations
• The design and anatomy of the Obligation extension, including the Obligation Codes value set
• Best practices for combining Obligations with Must Support in real‑world profiles
• Early adoption by initiatives in Canada, Europe, and beyond

You can read the full blog post here: From “Must Support” to Measurable Interoperability: Why FHIR Obligations Are a Necessary Next Step

And download the accompanying whitepaper here: Refining Conformance: An Analysis of the Evolution from Must Support to FHIR Obligations