DDI Specification

For the most up-to-date news on the development process of DDI ( summary), please visit the DDI Collaboration Wiki.

Latest version

DDI Lifecycle 3.2

DDI-Lifecycle is designed to document and manage data across the entire life cycle, from conceptualization to data publication and analysis and beyond. It encompasses all of the DDI-Codebook specification and extends it. Based on XML Schemas, DDI-Lifecycle is modular and extensible.

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DDI Codebook 2.5

DDI-Codebook is a more light-weight version of the standard, intended primarily to document simple survey data. Originally DTD-based, DDI-C is now available as an XML Schema.

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Previous versions

DDI Lifecycle 3.1

DDI 3.1 reflects (1) the correction of bugs identified by implementers using DDI 3.0, and (2) the resolution of the final URN structure to ensure persistent URNs for all identified elements. Note that DDI 3.1 is not backward compatible with DDI 3.0.

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DDI Codebook 2.1

DDI Codebook was the first version of the DDI standard to be published (Version 1 was released in 2000). DDI 2.0 was released in 2003, with version 2.1 following two years later. Version 2.* added coverage of aggregate data and geography.

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DDI Lifecycle 3.0

DDI 3.0, published in April 2008, represented a major advancement for DDI by fully incorporating XML Schemas and moving to a data life cycle approach. Element content for DDI 3.0 was developed by several Working Groups with the technical specification itself created by the Technical Implementation Committee (TIC).

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