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titleClinical Data HierarciesHierarchies
Gliffy Diagram
bordertrue
size600
displayNameSimple view of EDC Data
nameSimple view of EDC Data
pagePin1012
Gliffy Diagram
size600
displayNameSimple view of Dataset data
nameSimple view of Dataset data
pagePin1113

For ODM Version 2v2.0, there are two 2 forms of the clinical data hierarchy.  The full subject data hierarchy (Figure 1) is typical of usage within data collection tools such as EDC systems. The dataset hierarchy (Figure 2) reflects data tabulation formats that are typical of usage for data review and submission.

The ODM allows for both  internal and external keys. Internal keys, known as OIDs,  are used to designate entities within the model, and to allow cross-references between entities within and between ODM files.

Internal keys are not optimized for human use but are assumed to be unchanging.

External keys are any keys used by clinical personnel. They are typically represented in ODM metadata by an element Name attribute or a Description child element. They are intended to be useful for data review and interpretation.

The ODM allows for both  internal and external keys. Internal keys, known as OIDs,  are used to designate entities within the model, and to allow cross-references between entities within and between ODM files. Internal keys are not optimized for human use but are assumed to be unchanging. External keys are typically represented in ODM metadata by Name attributes or Description child elements. They are intended to be useful for data review and interpretation.

Kind of EntityIdentifying KeysRequired for Subject dataRequired for Dataset data
studyStudyOIDX
subjectabove plus SubjectKeyX
study eventabove plus StudyEventOID and StudyEventRepeatKeyX
item groupabove plus ItemGroupOID and ItemGroupRepeatKeyXX
itemabove plus ItemOIDXX
annotationkeys for the annotated entity plus SeqNumXX

A StudyOID uniquely identifies a study. A SubjectKey uniquely identifies a subject within a study. SubjectKeys are not intended to be used to identify a subject across studies.  

A StudyEventOID uniquely identifies a StudyEventDef within a study. However, there may be several study events of a particular type for a given subject. Thus, to fully identify a particular study event, we need the The StudyOID, the SubjectKey, the StudyEventOID, and a StudyEventRepeatKey are all needed to fully identify a particular study event.

Collected data always belongs to an ItemGroup but  but either form of the hierarchy may be used within a Clinical Data element.

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Within the ODM ReferenceData element,   ItemGroupData  does not relate to a study subject. 

Each item belongs to an item group. Beginning with ODM Version 2v2.0, Item Groups item groups can contain other item groups, Within an ItemGroupData instance, however, there may be only one 1 instance of an ItemOID. That is,   only the ItemOID is needed to uniquely identify an item within its item group.

Info

For clinical data collected in support of submissions to regulatory authorities where CDISC Data Standards data standards are required, the CDISC Study Data Tabulation Model (SDTM) and SDTMIG standards SDTM Implementation Guide detail the requirements for variables used to identify study subjects, study events, and timing and other data elements used in processing the clinical data.

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