The DDI Alliance Technical Committee is pleased to announce the final public review and vote on DDI-Codebook Version 2.6 (Release Candidate).
What is this?
DDI-Codebook is a metadata standard for defining a single study, including its variables, files, source materials, and basic study information. Version 2.6 is the next incremental update, focused on improving consistency, clarity, and interoperability -- without introducing disruptive changes.
This Release Candidate has already completed:
Technical review
Beta review
(both conducted during 2024–2025)
Based on feedback from those reviews, the Technical Committee made minor revisions to improve consistency and clarify field-level documentation.
What’s new in Version 2.6?
Version 2.6 introduces improvements in the following areas:
More consistent attributes for people and organizations
Better linking of access rules to specific content
Expanded use of typeOfXxxx to support controlled vocabularies, making metadata more structured and interoperable
More consistent use of controlled vocabularies through the element concept
Updated internal enumerations
A new DDI controlled vocabulary
Metadata access information
Use of SDTL, allowing clearer descriptions of file and variable derivations
How to review and comment
The full Release Candidate package is available on GitHub:
https://github.com/ddialliance/ddi-c_2
A complete change log is included in the package.
A Best Practices document will be published after Version 2.6 is formally published.
Public review period: 28 January 2026 through 28 February 2026.
Following the public review, Designated Member Representatives of the DDI Alliance will be asked to vote on the Release Candidate.
Comments and issues may be submitted directly in the GitHub repository (https://github.com/ddialliance/ddi-c_2).
Webinar for voters and reviewers
The Technical Committee will host a webinar at the start of the voting period to:
Explain the purpose and scope of Version 2.6
Highlight key changes
Answer questions from reviewers and voters
The primary audience is DDI Alliance voting members, but the webinar will be open to all interested participants. Details will be announced once scheduled.
If you have questions, please contact Wendy Thomas [wlt@umn.edu], Chair of the DDI Alliance Technical Committee.