An ItemGroupDef describes a type of variable or field grouping that can occur within a study.
The Repeating flag indicates that this ItemGroup may occur repeatedly within the containing element. Set Repeating to Simple when the ItemGroup repeats within the containing element and is not bound in any way. Repeating="Simple" is equivalent to the ODM v1.3.2 case where Repeating="Yes". Repeating values of Dynamic or Static indicate that the number of occurrences within the containing element is driven by the values in a codelist. Set Repeating to Dynamic when the ItemGroup repeats based on values in a codelist, and multiple repeats per codelist value may be created. Set Repeating to Static when the ItemGroup repeats based on values in a codelist, and only 1 repeat may occur per codelist entry.
Note, for cases where Repeating is set to Dynamic or Static, one ItemRef within the ItemGroup must include the Repeat="Yes" attribute to indicate that this variable references the codelist that establishes the Repeating behavior.
If IsReferenceData is Yes, this type of item group can occur only within a ReferenceData element. If IsReferenceData is No, this type of item group can occur only within a ClinicalData element. The default for this attribute is No.
In general, the Domain and Purpose attributes, as well as the Origin child element, carry information used in the submission context. The CommentOID attribute references a CommentDef element that allows annotations to the item group.
The Type attribute identifies the type of data structure the ItemGroupDef represents, including Form or Dataset. Note, ItemGroupDef Type="Form" replaces the ODM v1.x FormDef element.
The DatasetName, Domain, Purpose and CommentOID attributes, as well as the Origin element, could have constraints on individual ODM extensions, such as Define-XML or associated CDISC Metadata Guidelines. For example, DatasetName could be defined as sasName in Define-XML or associated CDISC Metadata Guidelines.
ODM v2.0 introduces nested ItemGroups, and ItemGroupRef elements may be added to ItemGroupDef to create hierarchical data structures of arbitrary depths. Nested ItemGroupDefs can be used for enhanced re-usability of ItemGroups, to represent semantic relationships between items, to represent items that share common behaviors such as skip logic, and to represent items that are displayed together.