1. The Role of Metadata in Census Data Dissemination
United Nations Regional Seminar on Census Data Dissemination and Spatial Analysis
Bangkok, Thailand
5-8 October 2010
United Nations Statistics Division i

2. Outline of presentation
What is metadata?
Basic roles of metadata
Types of metadata
Users of metadata
Metadata in census data dissemination
Metadata standards
Conclusion

3. What is metadata?
It is descriptive and structured information or documentation about data which:
informs users about the content, quality and condition of data;
guides on proper usage or interpretation of data;
describes the structure of datasets, explains, locates, or makes it easier to retrieve, use, or manage data;
provides information on the processes of production.
“Data that define and describe other data” (ISO definition)
“Information about information” (Dion, 2006) 3

4. Basic Roles of Metadata
Assist in retrieving and processing data
Support correct use of data
Provide transparency in data
Enhance interpretability or confidence of users in the information
Improve archiving, preservation, institutional memory over time 4

5. Types of metadata Structural metadata Reference metadata
provide information about the structure of the dataset
act as identifiers and descriptors of the data, making it possible to properly identify, retrieve and browse the data
Reference metadata
allow a thorough understanding and interpretation of the corresponding statistical data
Describe the concepts, definitions, methodology and quality of data; production and dissemination process, data access conditions, release policy, confidentiality, etc 5

6. Users of metadata
Metadata support the knowledge of potential user of statistical information. The major users include:
Users of statistical data
Producers of statistical data
Researchers on the development of statistical systems 6

7. Metadata in Census Data Dissemination
All tabulations of census data should include:
Census questions
Reason why the questions are asked
Conceptual definitions
Geographic hierarchies used
Changes since the previous census, regarding content, operational methods or geographic boundaries
Quality indicators (ex. coverage rates and item non-response)
Methodological note on the rules and methods of suppression
If a long-form sample is used...
Sampling variability of the results
(C&P, 2008)

8. Metadata standards
　Currently, metadata suffer from a lack of　 common standards and guidelines
Standardization:
ensures consistency and comparability of content
avoids duplication and diversity of definitions
ensures reduction in cost of data development 8

9. Metadata standards (cont’d)
Two international metadata standards are becoming well established
SDMX
DDI
a number of international agencies have endorsed SDMX; supported by the UN Statistical Commission
IHSN’s Microdata Management Toolkit uses the DDI metadata standard S 9

10. Conclusion Metadata are at the heart of the information management.
They should be an integral part of statistical dissemination strategies.
Standards for metadata management are important
Regional and international collaboration between NSOs is an important consideration 10

11. Points for discussion - What are the success factors of metadata?
Strategies?
Infrastrucure?
Resources?
- How to ensure the security of metadata?
- How “open” or “transparent” the metadata can be?
- How to improve standerdization of metadata?

12. Thank you !