The Data Documentation Initiative (also known as DDI) is an international standard for describing surveys, questionnaires, statistical data files, and social sciences study-level information. This information is described as metadata by the standard.

Begun in 1995,[1] the effort brings together data professionals from around the world to develop the standard. The DDI specification, most often expressed in XML, provides a format for content, exchange, and preservation of questionnaire and data file information. DDI supports the description, storage, and distribution of social science data, creating an international specification that is machine-actionable and web-friendly.[2]

Version 2 (also called "Codebook") of the DDI standard has been implemented in the Dataverse data repository and the data archives of the Inter-university Consortium for Political and Social Research. The latest version 3.3 (also called "Lifecycle") of the DDI standard was released in 2020.[3]

Member Institutions[4]

Normal Exit PeriodicService.php