Overview of Current Products

A description of all current DDI products available for use.


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


DDI-Codebook is a more light-weight version of the standard, intended primarily to document simple survey data.

Controlled Vocabularies

Controlled vocabularies play a critical role in metadata standards in terms of (1) semantics -- definition of the meaning of metadata elements, and (2) content -- declaration of instructions for what and how values should be assigned to elements.

XKOS - Extended Knowledge Organization System

XKOS leverages the popular Simple Knowledge Organization System (SKOS) vocabulary for managing statistical classifications and concept management systems.

SDTL - Structured Data Transformation Language

Structured Data Transformation Language (SDTL) is an independent intermediate language for representing data transformation commands.

DDI Agency ID Registry

The DDI Agency ID Registry enables you to obtain an agency ID from the DDI Alliance. Using this permanent identifier in your DDI instances allows you to specify the authoritative source of your data and metadata. The registry is connected with the global DNS system, allowing DDI URNs to be resolved using standard tools. The source code for the registry and several related tools is also available under an Open Source license from the web site. The DDI Registry is maintained by the DDI Alliance.

Developing Products of the Alliance

The DDI Alliance continues to develop new products to meet the needs of current and potential user group. These are proposed by members and supported by contributed work and funding from the Alliance as agreed to by the Executive Board. New products may be used to expand the coverage of existing DDI products or be published as stand-alone products that address a need in the DDI Community.