will make it easy for you to distinguish the Reference set view from other views, for example the SNOMED CT view or the Parent view.
| Custom-built subsets: Reference sets in Snow Owl | ||
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SNOMED CT is big: it's the most comprehensive clinical terminology in the world. It's also been around the block: today's SNOMED CT has evolved from terminologies first created in the mid-1960s. Growth has come both organically over time, but also by acquisition through mergers of other terminologies. The result is that some areas of SNOMED CT have inconsistent levels of detail. (A favorite example is Atomic power plant malfunction in watercraft, occupant of small unpowered boat injured.)
Therefore it's often necessary to extract a smaller collection of concepts from SNOMED CT. This is where reference sets come in handy. They are purpose-built mini-versions of the terminology that contain only the terms that are needed in a specific context, for example all terms needed in an emergency department or for cardiologists.
Snow Owl allows you to create and maintain different kinds of reference sets. They are named from the SNOMED CT Release Format 2 specifications, which are described in detail in the IHTSDO's Technical Implementation Guide .
When working with reference sets you will primarily use the
Existing reference sets are displayed in the
Reference Sets view on the right side of your screen. The shop icon
will make it easy for you to distinguish the Reference set view from other views, for example the SNOMED CT view or the Parent view.
If you want to check out a few reference sets (e.g. mental health, neurology), go to the B2i examples folder in the Reference Sets view.
Double-clicking an reference set will launch the
reference set editor (in the middle of your screen). The icon in the header indicates the type of reference set (e.g. the
icon for a simple type reference set).
The reference set editor is pretty easy to understand since it contains components from the SNOMED CT concepts view and the SNOMED CT concepts editor that you are already familiar with:
in the editor menu allows you to switch the view between a hierarchical and a flat list.
Did you know? Rather than a flat list of all reference sets for a particular type, reference sets are grouped by their parent. This is useful to create a reference set to group several child reference sets for easier navigation.
There are three types of reference sets used for creating subsets. They can be easily recognized by their dedicated icons:
Simple type reference set
Attribute value type reference set
Query type reference set
The simple type reference set is a plain grouping of concepts by user preferences. We will show you how to create one later in this chapter.
An attribute value type reference set allows associating a value concept with the referenced component. It can be used to extend the ontology with custom properties on the concept.
The members of a query type reference set are determined based on a semantic query.
Did you know: Query type reference sets and the generated simple type reference sets can be automatically updated. This is useful when the underlying terminology changes, for example when a new version of SNOMED CT is released. The action can be applied either on an individual intensional reference set or on the entire set of query type reference sets and will refresh all the generated simple type reference sets.
The reference set wizard will guide you through the process of creating a reference set. To launch it, pick one of the icons on the main tool bar. Each type of reference set has a different icon.
New
query type reference set
New
simple type reference set
New
simple map type reference set
New
complex map type reference set
New
attribute value reference set
Alternatively, you can right click on any of the main type categories in the Reference Set view. This will will also open the reference set wizard of the appropriate type. It can also be invoked with File > New.
As an example, we want to you show you how to create a new simple type reference set.
1. Click the
icon on the main tool bar to
launch the wizard.
2. Type a reference set description (here: Shoulder Reference Set) and select the referenced component type (here: SNOMED CT Concept). The wizard automatically creates a reference set identifier concept with the title as a description. Click "Finish" to proceed.
3. You may enter a commit comment in the subsequent dialog, then click "OK" to open the Reference set editor.
4. Your new reference set will appear in the reference set editor. The reference set description is displayed in the title. The list of reference set members is empty since there were no referenced components added yet.
5. To add referenced components go to the SNOMED CT View and choose a concept from the hierarchy (here: Finding of shoulder region). Right-click the concept and choose Add concept and descendents to the active reference set from the list. This will add the concept and all of its children to the reference set. If you want to add only this particular concept use Add concept to the active reference set.
6. The concept is now displayed in the reference set editor. The " matching members" indicates the number of components in the reference set. The small * asterisk in front of the editor title indicates unsaved changes.
7. To save your reference set, use the
icon in the main tool bar. The new reference set will also be incorporated in the hierarchy of the
reference set view as a "simple type reference set".
button. The browse button will give you access to the quick search that you are already familiar with: Type your search term, pick the concept you want to add from the search results, and hit Finish to add it to your reference set. Now the new member will be part of your reference set and you should be able to find it in the hierarchy.
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| Close encounters with the concept - Introducing the editor | Mapping |