Data Documentation Initiative (DDI): Data Documentation Initiative (DDI): Goals and BenefitsGoals and Benefits

Mary VardiganMary VardiganDirector, DDI AllianceDirector, DDI Alliance

Today’s Presentation

• What is DDI?

• History of the effort

• The DDI community

• DDI features, benefits, examples

• Relationship to SDMX and GSBPM

• Future directions

What Is DDI?

• An international specification for structured metadata describing social, behavioral, and economic data

• A standardized framework to maintain and exchange documentation/metadata

• A basis on which to build software tools• Currently expressed in XML – eXtensible

Markup Language

History

• 1995 -- First international committee established

• 2000 -- First DDI version published (aligned with codebooks, XML DTD-based)

• 2003 – DDI 2 published (support for aggregate/tabular data and geography added)

• 2003 -- Formation of the DDI Alliance, a self-sustaining membership organization

• 2008 – DDI 3 published (aligned with data lifecycle, XML Schema-based)

• 2010 – DDI rebranding – DDI Codebook (DDI 2 branch) and DDI Lifecycle (DDI 3 branch) development lines

DDI Alliance

• 30 members from around the world• Modest institutional membership fee -- entitles

members to help to shape the specification• Yearly meetings• Active working groups: Survey Design and

Implementation, Qualitative Data• New groups: Paradata, Administrative Data,

Disclosure

The DDI Community

www.ddialliance.org

The DDI Community

Projects and Organizations Using DDI

• Australian Bureau of Statistics

• Canadian Research Data Centres (RDC) Program

• CESSDA Data Portal

• DataFirst at University of Cape Town

• The Dataverse Network

• European Social Survey (ESS) and ESS-Edu-net

• Gallup Europe

Projects and Organizations Using DDI

• General Social Survey

• Institute for the Study of Labor – IZA, Germany

• LISS -- Longitudinal Internet studies in the Social Sciences, Netherlands

• National Survey of Family Growth, US

• UNICEF, Child Info – Monitoring the Situation of Children and Women

• World Bank -- International Household Survey Network (IHSN) and Microdata Management Toolkit

Products of the DDI Alliance

• Specifications for DDI Codebook and Lifecycle

• Controlled vocabularies

• Tools catalog

• Training

• Papers and presentations

DDI Tools

• Several DDI authoring tools now available

• Nesstar

• IHSN Microdata Toolkit

• Colectica

• Tools for DDI in Research Data Centers

DDI Training and Exploration

• Training available on demand in fundamentals of DDI

• Advanced workshops in Germany in September 2011

• DDI and Longitudinal Data

• DDI and Semantic Statistics

DDI Development Lines

• DDI Codebook (DDI 2 branch)– Reflects components of social science codebooks

– Includes descriptions at the study, file, and variable level

• DDI Lifecycle (DDI 3 branch)– Reflects research data lifecycle

– Optimized for reuse of metadata

Research Data Life Cycle

Research Data Life Cycle

•Initial concepts•Questions and answers•Grant info

•Questionnaire•Coded instrument•CAI metadata•Paradata

•Data specs•Recodes•Summary descriptive info

•Terms of use•Citation•Packaging info

•Catalog record•Indexing•Related publications

•Replication code•Publications

•Post-hoc harmonization•Data transformations

•Preservation metadata•Confidentiality•Add’l processing

DDI as backbone for structured metadata

CollectionConceptProcessin

g

Distribution

Discovery Analysis

SIP

AIP

DIP

CAI ToolsMQDS etc.

Information extracted from SPSS etc.

Archive

Custom Tools(e.g. Forms-based)

Statistical packagesOnline Analysis.

Search engines.Distribution Packages

Web information system

Data / Documents outside of DDI

DDI Lifecycle Features

• Machine-actionable

• Modular and extensible

• Multi-lingual

• Aligned with other metadata standards

• Can carry data in-line

• Focused on metadata reuse

DDI Lifecycle Features

DDI Lifecycle Features

• Support for CAI instruments

• Support for longitudinal surveys

• Focus on comparison, both by design and after-the-fact (harmonization)

• Robust record and file linkages for complex data files

• Support for geographic content (shape and boundary files)

• Capability for registries and question banks

Example – ComparativeCollaborative Psychiatric Surveys

www.icpsr.umich.edu/CPES

Explore a Variable

Compare Questions in Proximity

DDI and SDMX -- Statistical Data and Metadata eXchange

• Not competing but complementary• Two standards bodies talking with each other –

Recent meetings in Utrecht, Lisbon, and Washington, DC; next one in Luxembourg

• Goals and use cases– Document survey process end-to-end– Drill back from macrodata to microdata– Data discovery

Generic Statistical Business Process Model -- GSBPM

GSBPM, SDMX, and DDI

Future Directions

• Data model development• Additional controlled vocabularies• Training in DDI and SDMX• New tools – DDI from Blaise• New versions of both Codebook and Lifecycle

this year• Work starting on DDI 4.0

Questions?

• Mary Vardigan – vardigan@umich.edu