Sam Hume, DSC, Head of Data Exchange Technologies, CDISC

Since starting work on ODMv2 earlier this year the CDISC XML Technologies Team has made quite a bit of progress detailing proposed changes and new features. Much of this work is progressing concurrently, creating a broad set of ongoing discussions. To follow the ODMv2 development work the best place to begin is the ODM-XML page in the XML Tech space on the CDISC Wiki. Here you can find a list of the most recently updated pages, a list of JIRA tasks, a link to the decision log, and links to most other relevant aspects of the project.

The remainder of this post highlights some examples of ODMv2 development progress underway. It’s important to note that these highlights represent development in progress; changes prior to final implementation are likely.

One CRF representation improvement includes an enhanced version of the ODM Repeating ItemGroup that will enable the repeat to be driven by a code list so that each term in the code list represents one or more questions on a CRF.  Dynamic repeating ItemGroups can represent multiple observations per code list term, while static repeating ItemGroups are restricted to one observation per code list term. Repeating ItemGroups can optionally include a dynamically added “other” observation. The example below displays a Medical History CRF generated based on a body system code list.

Medical History.png

An early draft of the ODM RESTful API for metadata is available for discussion and features support for JSON. Thus, ODMv2 will be represented in formats other than XML. The API development will continue to include the other major ODM sections, including AdminData, ReferenceData, and ClinicalData. The example below shows the form metadata API. To support API use, we will register a new ODM media type with the Internet Assigned Numbers Authority (IANA).


As a data exchange standard, ODM supports a range of semantics. For ODMv2 we plan to enhance ODM’s ability to formally represent controlled vocabularies and standard terminologies published from CDISC and others, such as LOINC or SNOMED-CT. There is active development underway to explore how this might be done for use in MeasurementUnit and ItemDef. Other cases will be examined in the near future.

We’re also in the process of moving content created as ODM extensions back into the base ODM standard, including Define-XML and SDM-XML. For the Define-XML standard, new elements and attributes created in the Define-XML namespace will be examined to determine which should become part of ODM. We’re also evaluating the implementation of Dataset-XML for EDC, or support for the exchange of operational datasets. Work is also underway to add SDM-XML, the study design model in XML, into ODM. A review and refinement of SDM-XML is in progress prior to including it into the base ODM model. Moving these extensions into the ODM model will significantly expand the use cases addressed by the ODM standard.

As new features are debated and developed, their impact on the ODM model will be examined closely prior to implementation. In addition to refining the existing model, we plan to enhance the schema to represent more of the model’s rules and constraints. This approach has the benefit of enhancing the coverage provided by schema validation, as well as benefiting those that generate code based on the schema. A new set of schema naming conventions has been documented to support this work. We will also review the existing schema for consistency, including expanding opportunities for translating content with additional TranslatedText elements and broadening the schema extension mechanism.

There are quite a few features and changes under development not covered in this update. For example, we’ve had lengthy discussions on the best way to update the Length and SignificantDigits attributes. This post highlights some of the more significant ODMv2 changes underway. Periodically, I’ll provide progress updates with additional details and examples to help ODM implementers understand what’s coming.