Reference set metadata

Problem

Much of the metadata associated with a reference set could be carried within the SNOMED CT content itself, and yet it isn't. This has caused confusion trying to derive the meaning and purpose of a reference set from the reference set concept's terse name, and many owners of reference sets to produce documents and metadata repositories containing this content. All the more confusing for a consumer to chase down which repository or document to find out what the scope, purpose and meaning of a reference set is.

For implementers there are also annoying lacking pieces of metadata. For example the map reference sets provide no machine processable way to identify what code system a map refers to (other than SNOMED CT) or indeed which direction the map goes - the implementer just has to "know" and hardcode the specific map concepts to expect certain sources/targets.

It would be far preferable that this information was encoded with the content.

For the Australian extension, maintaining a metadata repository separately to the actual reference set concepts and content has become painful. We are seeking to pack the required information into the SNOMED CT content itself. For interest the attributes being currently published for SNOMED CT-AU reference sets are as follows, although not all of these need to be encoded as metadata they are an interesting example.

Reference set name	Adverse reaction agent reference set
Terminology	SNOMED CT-AU
Reference set developer	National Clinical Terminology Service
Description	Supports the accurate recording of the most common agents that may be responsible for causing adverse reactions. It is intended that this reference set be used in association with the Clinical manifestation reference set, which provides values describing the clinical manifestation of adverse events.
Scope	This reference set can be used: • Within implementations of the Adverse Reaction DCM (Adverse Reaction Detailed Clinical Model Specification. Sydney: NEHTA; 2015. v3.2.). • Within implementations where use-case specific reference sets for adverse reaction agents are yet to be developed. • As the basis for developing further use-case specific reference sets for adverse reaction agents through a process of constraint, or expanding upon. • Alongside other reference sets, such as any of the AMT medicinal or trade product reference sets to supplement the recording of non-medicinal agents.
Target client	This reference set can be used where developers are implementing The Agency clinical information models containing the Substance/Agent data element or the Adverse Reaction DCM.
Other clients	Australian e-health clinical information systems.
Definitive bindings	The Adverse reaction agent reference set is bound to the Substance/Agentdata element within the Adverse Reaction DCM.
Example of content	• 256350002 \|Almond\| • 387494007 \|Codeine\|
Date of initial release	20131130
Initial no. of members	1113
Development Approach last updated	20131130
Date of current release	20170430

Proposal

Develop a set of optional metadata attributes of a reference set that may be published about a reference set, and for each define a standard way to represent the attribute within SNOMED CT's RF2 data structures.

For example the "description" may use the Text Definition description type, or it could be an additional standard reference set which annotates each reference set concept with its description. The important part is that a standard way is defined to represent this information so that where it is provided it is done so consistently.

Steps to achieve this would be

collect metadata attributes currently being published about reference sets and merge/distill these to a distinct set, agreeing a name for each (seek this from SNOMED International documentation and the member nations existing publications)
collect metadata requirements which are currently not being met at all, for example the to/from code system for a map type reference set
create a catalogue that defines each attribute and the standard way to represent them in RF2 - note this may require SNOMED International to add content (such as reference sets and reference set descriptors) to the International Edition

While metadata may be required from SNOMED International it is NOT expected that SNOMED International would be required to populate all of these metadata attributes for existing reference sets.

In order to provide value incrementally and early, rather than a large up front analysis exercise, this is likely best approached by completing a small up front collection of non-controversial attributes followed by incremental addition of attributes as they are uncovered and consensus is achieved. Under no circumstances should we seek to define up front the approach to all conceivable metadata for a reference set before the approach to any of the metadata attributes is finalised and published.