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The UK's largest collection of digital research data in the social sciences and humanities

Metadata standards

The Archive has been a driver and implementer of metadata standards.

We actively work with the following three standards:

DDI logo

The Data Documentation Initiative (DDI) is the de facto metadata specification for social science data, and has a large and active international community of users and developers. It was originally created to capture the information found in survey codebooks, and it is used basic study-level catalogue metadata and rich variable description for survey files by many data publishers across the world. Data publishers regularly make it available as DDI XML.and via OAI-PMH for exposing their holdings.

It is maintained by the Data Documentation Initiative Alliance, a membership-driven consortium including universities, data archives, and international organisations.

The Archive's use of the DDI Codebook: We use the DDi 2.5 for our collection-level records in the Data Catalogue and in our Nesstar online data browsing system.

DDI Working Group on Qualitative Data: In 2013, this group produced a detailed and complex model to accommodate the widest range of possibilities and use cases for qualitative data. QuDEx represents a very simple subset of this larger model.

Text Encoding Initiative logo

The Text Encoding Initiative (TEI) is a widely used metadata standard for describing textual documents. It is maintained by a consortium which collectively develops and maintains a standard for the representation of texts in digital form.

The Archive's use of the TEI: While the TEI has many profiles, the UK Data Service uses it for:

  • Structural mark-up of textual qualitative data
  • Three mandatory TEI header elements
  • Body elements: turn takers, paragraphs, headers
  • Inline tags: corrections, errors


The Qualitative Data Exchange Schema (QuDEx) allows users to discover, find, retrieve and cite complex qualitative data collections in context.

The schema is complementary to DDI and enables:

  • Highly structured and consistently marked-up data
  • Rich descriptive metadata for files e.g. interview characteristics, interview setting, type of object
  • Logical links between data objects: text to related audio, images, and other research outputs
  • Preserves references to annotations performed on data
  • Common metadata elements that enable federated catalogues across providers and borders

The standard is maintained by the UK Data Archive, and the project overview and outputs can be accessed from the DExT site.

The Archive's use of QuDEx: The UK Data Service's QualiBank uses the schema, along with the TEI and DDI Codebook

Schema and documentation

  • Schema The latest version of the QuDEx Schema v3.01
  • Release notes for the Schema version 3.0
  • Open issues A collection of the open QuDEx issues
  • A reference guide to QuDEx elements and attributes which we hope may be expanded to provide further implementation support in future versions. A list of relevant acronyms is provided at the end of this document providing basic definitions (not technical details) of QuDEx and other related concepts
  • The latest version of the QuDEx Object Model v3.0d
  • QuDEx mapping from Atlas-ti to QuDEx XML
  • Full instance of the XML containing most elements and attributes
  • Sample instance Atlas-ti XML based on sample data
  • Sample METS Supporting document for archiving of QuDEx and other material
  • QuDEx Viewer A basic demo for viewing QuDEx files (requires Tomcat server to run)