DDI Discovery Vocabulary
DDI Lifecycle – Moving Forward
21.10.2012 – 26.10.2012
Thomas Bosch
M.Sc. (TUM)postgraduate student
http://boschthomas.blogspot.comGESIS - Leibniz Institute for the Social Sciences
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Agenda
• 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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Why DDI as Linked Data?
• 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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How was the DDI Ontology developed?
• 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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Discovery Use Case
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study | coverage
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instrument | question | concept
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values | value labels
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variable | descriptive statistics
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logical dataset | dataset | data file
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conceptual model
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Thank you for your attention!
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