DDI Lifecycle Working Group Minutes 2026-07-21

[DanSmith]

Minutes 2026-07-21

Attendees

• Dan Smith @DanSmith
• Guillaume Duffes @duffgui
• Jeremy Iverson @jeremyiverson
• Romain Tailhurat @romaintailhurat
• Hayley Mills @HayleyMills
• Wendy Thomas @wlthomas
• Wolfgang Zenk-Möltgen @moeltgen

Apologies:

• Franck Cotton @FranckCo

Quick recap

The meeting served as a kickoff for the DDI Lifecycle working group, with Dan providing an update on the current development status of version 4.0 and plans for version 4.1. The group discussed potential areas of focus for future development, including simplification of the dataset structure, alignment with Common Core, CDI and DCAT, and support for digital behavioral data. Romain raised the idea of adding a 3.4 version for Lifecycle, which Wendy noted would require careful consideration by the technical committee to avoid divergent development. Wolfgang highlighted the need for better support in documenting digital behavioral data, and Hayley mentioned interests in administrative and clinical data. The group also discussed the process for working together, agreeing to use GitHub for issue tracking and considering monthly meetings. Wendy suggested utilizing a shared Google space for collaborative documents, and the need for a chair for the working group was acknowledged.

Next steps

Dan

• Write up and post the meeting notes.
• Set up a Doodle poll to determine the best recurring meeting time for the group.
• Ensure all group members have access to the DDI Lifecycle Google Drive space.

Romain (or Franck)

• Lead the creation of a proposal for a compatibility 3.4 version of DDI Lifecycle, including specific content to backport (e.g., controlled vocabulary code value, cardinality for concepts) and clear guidelines for the 3.X line.

Collaboration

• Group: Review Knut's draft text for the DDI Lifecycle media type registration and provide feedback.
• Group: Consider and propose topics for the face-to-face cross-group meeting in spring (March/April) at GESIS.
• Group: Elect a chair (or co-chairs) for the working group at the next meeting.
• Group: Create a contributor/process document and templates for GitHub issue types.
• Group: Use GitHub Discussions for online collaboration moving forward.

Summary

DDI Lifecycle Version Development Updates

The team discussed the current development status of DDI lifecycle version 4.0, which is expected to release as a release candidate in August instead of July due to remaining issues. Dan outlined plans for version 4.1, focusing on simplification through reduced nesting and more precise properties to improve implementation and serialization, particularly for RDF. The group then began discussing individual interests for future development, with Dan suggesting simplification of dataset structures and alignment with Franck's W3C VVD work as potential areas of focus.

3.x Branch Model Discussion

Romain discussed the need to step back from discussing versions 4.1 and 4.2, as he had previously proposed creating a 3.x branch for lifecycle. Dan agreed with the ideas and suggested additional alignment with Common Core could be beneficial, and code value and populations as additional back ports, with Romain leading a proposal for a 3.4 version release that would include specific backward-compatible changes from 4.0. The team planned to bring up the 3.x model discussion with the technical committee, with Wendy potentially providing input on the topic.

Digital Data Documentation Framework Challenges

Wolfgang discussed the challenges of documenting digital behavioral data, including social media and web tracking data, within the existing DDI LiSA framework. He noted that colleagues are working on fitting these properties into the system and potential proposals for additions or changes may arise from this work. The group considered potential overlap with the current qualitative working group and administrative data efforts, with Wendy suggesting that these areas could benefit from cross-group coordination or a separate content group to address requirements across different DDI products.

Clinical Data Measures Challenges

The team discussed challenges with clinical data measures and controlled vocabularies in the Lifecycle model. Hayley raised concerns about population and universe definitions, while Romain highlighted issues with measurement types lacking clear guidelines and controlled vocabularies. Dan explained that version 3.3 introduced new measurement types and that the 4.0 release will align population definitions with DDI Common Core standards. Romain suggested involving domain experts in creating controlled vocabularies and requested improvements to how controlled vocabularies are implemented, particularly regarding identifier matching and RDF SCOS vocabulary integration.

DDI Codebook Updates Discussion

The team discussed updates to DDI Codebook 2.6 and the importance of maintaining alignment across products. Wendy emphasized the value of working with the CV Committee and DDI team, highlighting their expertise in developing descriptions and their willingness to collaborate with recommended sources. Knut mentioned the need for knowledge about the DDI lifecycle and announced the formation of a metadata publication and access working group to handle metadata registration and reviews.

DDI Lifecycle Registration Timeline

The group discussed the timeline for the DDI lifecycle registration process, with Knut suggesting they should wait to see how the current codebook process goes before proceeding with the lifecycle application, potentially starting in autumn. Knut shared a draft of the lifecycle registration form in a public GitHub repository for the group to review. Wendy announced plans for a face-to-face meeting in March or April at Gesus and Kolm, where the groups will discuss bigger topics for Lifecycle moving into the next versions, with input from CDI and the technical committee.

Product Group Development Planning

The team discussed establishing a product group to address joint development issues and larger scope topics like lifecycle identification and versioning rules. They agreed to create a contributor document and issue templates for the GitHub repository. The group decided to hold monthly standing meetings with a Doodle poll to determine the best time, and they identified the need to elect co-chairs for the working group to serve as primary contacts with the scientific board.