Requirements-Value Sets

A value set is a collection of codes from one or more code systems. The definition of the value set may be either an enumeration (extensional) or an expression (intentional)

Requirement	Value sets must be able to be identified in a globally unique way.
Rationale	Value sets need to be explicitly referenced in static models, implementation guides and context bindings. This can only occur if they're uniquely identified with no possibility of confusion
Methodology	mif-vocabulary-model.xsd/ValueSet/@id

Requirement	Value sets must be able to be given a human-readable label
Rationale	Value sets need to be talked about and understood by human beings and globally unique identifiers aren't terribly useful for humans
Methodology	mif-vocabulary-model.xsd/ValueSet/@name

Requirement	Some value sets need to be able to be marked as "unchangable"
Rationale	With some value sets, there's an identified purpose for the value set and the definition can change over time, so long as the revised set of codes still reflects the original purpose. However, for other value sets, there is no clearly expressible purpose. There is simply an arbitrary set of codes. Anyone who wants that particular arbitrary set can reference the value set. Because the defining characteristic of the value set is the codes themselves, it is not safe for the definition of the value set to ever be revised. As well, those who reference the value set need to have confidence that it's not going to change.
Methodology	mif-vocabulary-model.xsd/ValueSet/@isImmutable

Requirement	Value sets must be able to be uniquely identified
Rationale	Value sets need to be explicitly referenced in static models, implementation guides and context bindings. This can only occur if they're uniquely identified.
Methodology	mif-vocabulary-model.xsd/ValueSet/@id