DDI 3
Welcome to the site for Version 3 of the Data Documentation Initiative (DDI). The DDI is an XML specification for social science metadata that is being developed by an international group called the DDI Alliance.
DDI 3 represents a major advancement for DDI by fully incorporating XML Schemas and moving to a data life cycle approach. Element content for DDI 3.0 has been developed by several Working Groups with the technical specification itself created by the Technical Implementation Committee (TIC).
Examples of DDI 3 have been developed for the Proof of Concept for DDI 3.0 and provide a good source of information on the potential applications of DDI 3. The XML files may be valid only for Candidate Release 3.0 or the published version of 3.0.
The Bylaws of the Alliance mandate an open Public Review period during which the community may comment on a major release like Version 3.0. This review period occurred in Spring 2007, with Version 3.0 then issued as a Candidate Release, following approval by the DDI Alliance in May 2007 at its annual meeting.
On April 8, 2008, the Version 3.0 Candidate Release was made available in final form. After a short review period the DDI Alliance voted to publish the specification officially. The final published package was made available on April 28.
DDI 3.1 reflects the correction of bugs and resolution of the final URN structure to ensure persistent URNs for all identified elements. These corrections reflect the results of implementation projects using DDI 3.0. Note that DDI 3.1 is not backward compatible with DDI 3.0. A change file in the download package identifies which changes were backward compatible and the steps to take to move current DDI 3.0 instances to DDI 3.1.
On May 25, 2009, the DDI Alliance Expert Committee voted to publish the DDI 3.1 specification following minor corrections and resolution of the URN structure. DDI 3.0 was published on October 18, 2009.
In November 2008 25 individuals came together to develop a set of best practices for DDI 3.
The documents are the first attempt to define procedures for using DDI 3 optimally and as such are not considered "final." The best practice authors and editors welcome your feedback on the usability of the documents and priorities for new best practices. Please send your comments and suggestions to ddi-bp-editors@icpsr.umich.edu.
Tools
DDI 3 Editor-Lite
A variety of tools have been developed or are under development for working with DDI. These can be found on the DDI Tools site.
Understanding DDI 3.0
- Field-Level Documentation Generated from the XML Schemas
- Schema Descriptions (PDF 55K) -- Textual descriptions of the schemas
- Supplementary documentation
- XML Schema Tutorial -- A WC3 resource for learning about schemas
- UML Tutorial (MSWord) -- A short guide to Universal Moduling Language using the SDMX information model
DDI 3.0 Final Schema and Documentation
The XML Schema files of DDI 3.0 are also available for online usage.
Proof of Concept for DDI 3.0
The DDI Alliance Bylaws require a demonstration of Proof of Concept before official publication of any change to the DDI specification. We provide this information in a table, distinguishing between use cases and implementations.
License and Credits
DDI 3.0 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 3.0 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. See also the GNU General Public License Web site.
Other DDI documents are distributed under Creative Commons licenses.
The development of DDI 3.0 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 3.0 were made by many individuals and organizations.
DDI 2.1 to 3.0 Conversion
DDI 2.1 to 3.1 Mapping
Correspondence Mapping
The following three files document the correspondence between DDI 2.1and DDI 3.0 as it will appear in a revised edition of Part I of the technical specification. Please read both the Readme file and Translation Instructions prior to working with the spreadsheet.
Stylesheet Mapping
This example shows a correspondence prepared for the purpose of translating ICPSR materials to DDI 3.0.
Mapping in the form of the DDI 2.1 tree structure (.txt)
Understanding DDI 3.1
- Field-Level Documentation Generated from the XML Schemas
- Schema Descriptions (PDF 55K) -- Textual descriptions of the schemas
- Supplementary documentation
- XML Schema Tutorial -- A WC3 resource for learning about schemas
- UML Tutorial (MSWord) -- A short guide to Universal Moduling Language using the SDMX information model
DDI 3.1 Final Schema and Documentation
The XML Schema files of DDI 3.1 are also available for online usage.
Proof of Concept for DDI 3.1
The DDI Alliance Bylaws require a demonstration of Proof of Concept before official publication of any change to the DDI specification. We provide this information in a table, distinguishing between use cases and implementations.
License and Credits
DDI 3.1 XML Schema is free software: you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version.
DDI 3.1 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. See also the GNU General Public License Web site.
Other DDI documents are distributed under Creative Commons licenses.
The development of DDI 3.1 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 3.1 were made by many individuals and organizations.
DDI 3.0 to 3.1 Conversion
DDI 3.0 to 3.1 Mapping
The specification file contains a change document which lists all changes, whether they are backward compatible, and the changes required to move from 3.0 to 3.1. A longer document will be provided soon.
