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MRCM Reference Set

Attribute

Autopopulated From

MRCM attribute domain reference set

domainConstraint

FROM |MRCM domain reference set| as D, |MRCM attribute

domain reference set

| as AD

WHERE D.referencedComponentId = AD.domainId

MRCM domain reference set

domainTemplateForPrecoordination

D.domainConstraint, AD.grouped, AD.attributeCardinality, AD.attributeInGroupCardinality, AR.rangeConstraint

FROM

Scg expression

ShowParts	term

111115|MRCM domain reference set|

as D,

Scg expression

ShowParts	term

111115|MRCM attribute domain reference set|

as AD,

Scg expression

ShowParts	term

111115|MRCM attribute range reference set|

as AR

WHERE D. referencedComponentId = AD.domainId AND AD. referencedComponentId = AR.domainId

MRCM domain reference set

domainTemplateForPostcoordination

MRCM attribute range reference set

attributeRule

...

As described in Section 2.2, one of the key use cases for the SNOMED CT MRCM is to assist in the consistent authoring and validation of SNOMED CT concepts. With this in mind, the following features were included to optimize the MRCM for use in precoordinated content development:

The
Scg expression
ShowParts term
111115|MRCM domain reference set|
and the
and the
Scg expression
ShowParts term
111115|MRCM attribute domain reference set|
include
include attribute domains defined in terms of the lowest common supertype permitted in the inferred view (i.e. after classification of the concept being authored);
The
Scg expression
ShowParts term
111115|MRCM domain reference set|
includes
includes the proximal primitive constraints and mandatory defining relationships required to support proximal primitive modelling in each domain (in the stated view);
The
Scg expression
ShowParts term
111115|MRCM domain reference set|
includes
includes a general domain template, which can be used for authoring any content in the given domain using either proximal primitive modelling or proximal parent modelling authoring methods. Please note that this general domain template may be further constrained to support the specialized modelling requirements of specific subhierarchies in the given domain.
The
Scg expression
ShowParts term
111115|MRCM domain reference set|
and the
and the
Scg expression
ShowParts term
111115|MRCM attribute domain reference set|
use
use domains defined in terms of a single top-level hierarchy. This enables concepts being authored to be tested for subsumption with each domain concept, using techniques that are relatively simple to implement (e.g. using a transitive closure table).
The
Scg expression
ShowParts term
111115|MRCM attribute range reference set|
specifies
specifies the valid set of values (rangeConstraint) for each attribute used in the authoring of precoordinated content.
The
Scg expression
ShowParts term
111115|MRCM attribute range reference set|
also
also includes a set of attribute rules that incorporate the domain, grouping, cardinality and range constraints together into an expression constraint, to support the efficient implementation of content validation.
The ruleStrengthId attribute in the
Scg expression
ShowParts term
111115|MRCM attribute domain reference set|
and the
and the
Scg expression
ShowParts term
111115|MRCM attribute range reference set|
allows
allows both mandatory rules (resulting in errors) and optional rules (resulting in warnings) to be specified.
The contentTypeId attribute in the
Scg expression
ShowParts term
111115|MRCM attribute domain reference set|
and the
and the
Scg expression
ShowParts term
111115|MRCM attribute range reference set|
allows
allows the scope of each rule to be restricted to a particular type of SNOMED CT content, including:
- All SNOMED CT content – for rules which apply to both precoordinated and postcoordinated content;
- All precoordinated SNOMED CT content – for rules which apply to all precoordinated content (but not necessarily to postcoordinated content);
- New precoordinated SNOMED CT content only – for rules which apply to newly authored precoordinated content, which may not necessarily be valid for all existing content; and
- All postcoordinated SNOMED CT content – for rules which apply to all postcoordinated content (but not necessarily to precoordinated content).

...

The optimizations described in section 6.3.1 for use in SNOMED CT concept authoring, can also make the authoring and validation of SNOMED CT expressions, expression constraints and queries more efficient. In addition to these general authoring features, the

Scg expression

ShowParts	term

111115|MRCM domain reference set|

also

also includes a general domain template, which is designed to support the authoring of any postcoordinated content in the given domain. Once again, this general domain template may be further constrained to support specialized modelling requirements for a specific use case. The rules included in the

Scg expression

ShowParts	term

111115|MRCM attribute range reference set|

also

also allow some attributes to have a larger range of possible values when used to author postcoordinated content (compared to the authoring of precoordinated content).

Please note that SNOMED CT expression constraints and queries used on a substrate that includes only precoordinated content must use the MRCM rules that apply to

Scg expression

ShowParts	term

111115|All SNOMED CT content|

or

Scg expression

ShowParts	term

111115|All precoordinated SNOMED CT content|

, while expression constraints and queries used on a substrate that includes postcoordinated content may use the less restrictive rules (e.g. broader ranges) that apply to

Scg expression

ShowParts	term

111115|All postcoordinated SNOMED CT content|

(in additional to the rules that apply to

Scg expression

ShowParts	id

111115|All SNOMED CT content|

).
When authoring SNOMED CT expression constraints and queries, the cardinalities specified in the

Scg expression

ShowParts	term

111115|MRCM attribute domain reference set|

should

should be used to determine sensible cardinality constraints to apply to specific attribute refinements. In particular, a cardinality constraint in an expression constraint or query should be the same, or stricter than the cardinality for the corresponding attribute in the MRCM rules.

...

In a similar way to how the MRCM can be used for postcoordinated expression authoring, the MRCM can also be used to support Natural Language Processing (NLP), as described in section 2.4. When terms used in the free text are associated with a particular SNOMED CT concept, this concept can be tested for subsumption against the domains in the

Scg expression

ShowParts	term

111115|MRCM domain reference set|

. If the concept is found to belong to one of the domains, then the

Scg expression

ShowParts	term

111115|MRCM attribute domain reference set|

can

can be used to determine its possible attributes, and the

Scg expression

ShowParts	term

111115|MRCM attribute range reference set|

used

used to determine these attribute's possible values. These rules can be used to indicate possible ways in which this concept may be linked (via suitable SNOMED CT attributes) to concepts found in the surrounding text.

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When a new or updated rule is introduced to the MRCM, it may take a period of time before all existing content conforms to the new rule. In these situations, a content type of

Scg expression

ShowParts	term

111115|New precoordinated SNOMED CT content only|

can

can be used, to ensure that all new content obeys the rule. Over time, as the old content is updated to reflect the new rule, the content type may be changed to either

Scg expression

ShowParts	term

111115|All precoordinated SNOMED CT content|

or

Scg expression

ShowParts	term

111115|All SNOMED CT content|

. This approach can be used to ensure that all new content added to SNOMED CT conforms to high quality concept model rules, even though reviewing and correcting existing content may take additional time.

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As described in Requirement D.6, the international MRCM rules defined by the IHTSDO must be able to be extended and adapted by organizations developing SNOMED CT extensions, to support the concept model requirements of their extension content.
To support this requirement, SNOMED CT extension developers will be able to copy the international MRCM rules defined by the IHTSDO into one or more extension MRCM reference sets and edit these reference sets to add new rules and restrict or extend the existing rules as required. New MRCM reference sets created for a SNOMED CT extension must be designed to ensure consistency and data integrity between editions. Please note that if no changes to the SNOMED CT concept model are required to support an extension, no additional MRCM reference sets need to be created, as the international MRCM can be reused by the extension.

The

Scg expression

ShowParts	term

111115|MRCM Module Scope Reference Set|

is

is designed to allow extension developers to specify which MRCM reference sets should be applied to the content in each module. The

Scg expression

ShowParts	term

111115|MRCM Module Scope Reference Set|

should

should therefore be referred to, to determine whether an extension is reusing the international MRCM, or using a customized extension MRCM to support its content.

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