1. Leveraging the DDI Model for Linked Statistical Data
in the Social, Behavioural, and Economic Sciences
DC 2012
05.09.2012
Thomas Bosch Richard Cyganiak
GESIS – Leibniz Institute for the Social Digital Enterprise Research Institute,
Sciences, Germany Ireland
thomas.bosch@gesis.org richard@cyganiak.de
Joachim Wackerow Benjamin Zapilko
GESIS – Leibniz Institute for the Social GESIS – Leibniz Institute for the Social
Sciences, Germany Sciences, Germany
joachim.wackerow@gesis.org benjamin.zapilko@gesis.org

2. Agenda
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3. What is DDI?
• DDI (Data Documentation Initiative)
• Established international standard for the documentation and
management of data from the social, behavioral, and economic
sciences
• Data model for statistical data
• Supports the entire research data lifecycle
• Focus on microdata
• Structured high quality metadata
• enable secondary analysis without the need to contact the primary
researcher
• Enables the re-use of metadata of existing studies for
designing new studies
• Currently specified in XML Schema
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4. How was the DDI Ontology developed?
• DDI subset
• of the most important DDI elements
• Use cases
• Experts in the statistics domain formulated use cases which are seen
as most significant to solve frequent problems
• Most important use case: discover microdata connected with multiple
studies
• Leverage existing DDI-XML docs to DDI-RDF automatically
• Direct mapping
• Generic mapping (Bosch and Mathiak, 2011)
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5. Why DDI as Linked Data?
• Currently no such ontology available
• To increase visibility of data holdings using mainstream Web
technologies
• To open DDI to the Linked Data community
• To process DDI-RDF by RDF tools
• To link DDI-RDF to other RDF data
• To better identify opportunities for merging datasets
• To enable inferencing
• To research microdata within the LOD cloud
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6. What other metadata standards
vocabularies are used?
• Dublin Core Metadata Element Set, Version 1.1
• DCMI Metadata Terms
• SKOS
• SDMX  RDF Data Cube Vocabulary
• ISO/IEC 11179
• ISO 19115
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7. Discovery Use Case
• Which studies are connected with a specific coverage consisting of the 3
dimensions: time, country, and subject?
• What questions with a specific question text are contained in the study
questionnaire?
• What questions are connected with a concept with a specific label?
• What questions are combined with a variable with an associated coverage
consisting of the 3 dimensions time, country, and subject?
• What concepts are linked to particular variables or questions?
• What representation does a specific variable have?
• What codes and what categories are part of this representation?
• What variable label does a variable with a particular variable name have?
• What‘s the maximum value of a certain variable?
• What are the absolute and relative frequencies of a specific code?
• What data files contain the entire dataset?
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8. 8

9. study | coverage
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10. 10

11. instrument | question | concept
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12. 12

13. 13

14. values | value labels
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15. 15

16. 16

17. variable | descriptive statistics
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18. 18

19. 19

20. logical dataset | dataset | data file
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21. 21

22. 22

23. conceptual model
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24. 24

25. Acknowledgements
• Archana Bidargaddi (NSD - Norwegian Social Science Data Services, Norway)
• Franck Cotton (INSEE - Institut National de la Statistique et des Études
Économiques, France)
• Richard Cyganiak (DERI - Digital Enterprise Research Institute, Ireland)
• Daniel Gilman (BLS - Bureau of Labor Statistics, USA)
• Marcel Hebing (SOEP - German Socio-Economic Panel Study, Germany)
• Larry Hoyle (University of Kansas, USA)
• Jannik Jensen (DDA - Danish Data Archive, Denmark)
• Stefan Kramer (CISER - Cornell Institute for Social and Economic Research, USA)
• Amber Leahey (Scholars Portal Project - University of Toronto, Canada)
• Abdul Rahim (Metadata Technologies Inc., USA)
• John Shepherdson (UK Data Archive, UK)
• Dan Smith (Algenta Technologies Inc., USA)
• Humphrey Southall (Department of Geography, UK Portsmouth University, UK)
• Wendy Thomas (MPC - Minnesota Population Center, USA)
• Johanna Vompras (University Bielefeld Library, Germany)
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26. Thank you for you attention!
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