DDI-Codebook 2.5


DDI-C 2.5 Development History

DDI Codebook Version 2.5 was published on January 17, 2012, after approval by the DDI Expert Committee on November 18, 2011. This version is an XML Schema. It incorporates new substantive elements requested by the community and is designed to make it easier to migrate documents to DDI Lifecycle for those interested in doing so.

DDI Codebook Version 2.5 was modified on January 29, 2014. This is a sub-minor version change (version 2.5.1) which DOES NOT change the namespace of DDI-C. Modifications corrected an omission of DataFingerprint from 2.5, relaxed cardinality to support multiple languages, and expanded the documentation.

DDI Codebook 2.5 is backward compatible with DDI 2.1. A change log in the download package identifies all changes. A supplemental change log identifies changes found in the sub-minor version 2.5.1.

XML Schema and Documentation

Download DDI Codebook 2.5.1 (zip 2.6MB)

The XML Schema files of DDI 2.5 are also available for online usage. 

Understanding DDI Codebook 2.5

Linked Field-Level documentation

Updates to DDI Codebook 2.5

Detailed Changes to DDI Codebook 2.5

Supplemental Changes to DDI Codebook 2.5

Updating Existing DDI Codebook Instances to Version 2.5

License and Credits

DDI Codebook 2.5 XML Schema is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version.

DDI Codebook 2.5 XML Schema is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.

Other DDI documents are distributed under Creative Commons licenses.


The development of DDI Codebook 2.5 draws on earlier DDI versions and work of the committees and individuals who developed them as well as the collective ideas, needs, and work of the Expert Committee of the DDI Alliance. Major contributions to DDI Codebook 2.5 were made by many individuals and organizations.

For questions, please contact the DDI Secretariat