Scheme Groups

All schemes in DDI have a scheme group structure that allows users to identify sets of scheme objects and scheme groups that have specific relationships to each other. These may be related by subject, concept, universe, usage, or any relationship defined by the user. Because these groups are created by referencing the objects and groups they contain a single object can move into and out of multiple groupings over time.

These groups are administrative in nature and cannot be used to include a set of objects in another scheme or usage. For example, a QuestionGroup cannot be referenced by a QuestionConstruct as a set of objects.