1. Dissemination Workshop for African countries on the Implementation of International Recommendations for Distributive Trade Statistics May 2008, Addis Ababa, Ethiopia
UNITED NATIONS STATISTICS DIVISION
Trade Statistics Branch
Distributive Trade Statistics Section

2. Outline of the presentation
National reporting
Statistical confidentiality
Data dissemination timetable
Data revisions
International reporting
List of data items on DTS recommended for international reporting

3. National reporting Data dissemination Key activity of NSOs
Responsibilities of NSOs
Provide policy makers, business community and other users with high quality statistical information
Motivate respondents to participate in statistical surveys
Protect confidentiality of respondents

4. Statistical confidentiality
Most of the information about individual statistical units classified in section G of ISIC, Rev.4 is considered to be confidential
Statistical confidentiality is necessary in order to gain and keep the trust of:
Those required to respond to statistical surveys
Those using the statistical information
UN Fundamental Principles of Official Statistics (the sixth principle)
National Statistical Laws or other supplementary governmental regulations
National definitions of confidentiality and rules for microdata access may differ, but they should be consistent with this fundamental principle

5. DTS and statistical confidentiality
NSOs usually disseminate DTS in the form of various statistical tables
The statistical confidentiality is protected if tabulated data do not allow statistical units to be identified either directly or indirectly, thereby disclosing individual information
Direct identification - if data of only one statistical unit are reported in a cell
Indirect identification - if individual data can be derived from disseminated data (e.g. because there are too few units in a cell, or because of the dominance of one or two units in a cell)

6. Statistical disclosure control
Set of methods to reduce the risk of disclosing information on individual units
Manifest themselves at the dissemination stage, however
Pertinent to all stages of statistical production process
Disclosure control methods - attempt to find an optimal balance between the improvement in confidentiality protection and the reduction in data quality
Identification of sensitive cells - first step in statistical disclosure control
Sensitive cells – cells that tend to reveal directly or indirectly information about individual statistical units

7. Methods for protecting confidentiality
Aggregation
A confidential cell in a table is aggregated with another cell and then the information is disseminated for the aggregate and not for the two individual cells
Suppression
Removing records from a database or a table that contains confidential data
Primary suppression - values in sensitive cells are not published while the original values of the others are
Secondary suppression - some other cells are also suppressed to guarantee the protection of the values under the primary suppression
Other methods
Control rounding – the original value of each cell is modified by rounding it up or down to a near multiple of a base number
Perturbation – linear programming variant of the controlled rounding technique

8. Confidentiality rules for DTS
Rules for protecting confidentiality of DTS - should be in line with the provisions of countries national legislation and practice
Confidentiality criteria
Number of units in a tabulation cell
Dominance of a unit or units contribution over the total value of a tabulation cell
Decision in respect to the exact definition of the confidentiality criteria in terms of number of units per cell and percentage of dominance - left to the NSOs
Confidentiality rules may be relaxed in individual cases by requesting the permission of the dominating respondent (s) to disclose their data

9. Recommendations
Countries are encouraged to develop their own statistical disclosure methods suiting best their specific circumstances
If suppression is preferred as a method for protecting confidentiality of DTS
Any data deemed confidential should be reported in full detail at the next higher level of classification that adequately protect confidentiality
The confidentiality protection must result in a minimum loss of information

10. Data dissemination timetable (1)
Advance release calendar
Guarantees well established relations between NSOs as producers of DTS and the user community
Countries should develop and announce in advance the precise dates at which DTS statistics will be released
To be posted in the beginning of each year on the country’s statistical office website
Timelines of DTS data
Monthly – 45 days after the reference month
Quarterly – 3 months after the end of the quarter
Annual – 18 months after the end of the year

11. Data dissemination timetable (2)
Issues of importance for the development of advance release calendar
Timing of collection of initial data from major DTS surveys
To what extent data derived from the major data sources are subject to revisions
Timing of preparation of important national economic policy documents that need DTS as inputs
Modes of data dissemination

12. Data revisions
Essential part of countries practices on compilation of DTS
Occur as a consequence from the trade-off between the timeliness of published data and their reliability, accuracy and comprehensiveness
Conducted for the benefit of users - to provide them with data that are as timely and accurate as possible
Affect both annual and short-term DTS but are more pronounced for the short-term data

13. Reasons for revision
Revisions due to “normal” statistical procedures (current revisions) - conducted at regular intervals of time
New information becomes available
Change in the methodology
Change in data source
Change of base year
Revisions due to the correction of errors that may occur in source data or in processing
Special revisions - carried out at longer, irregular intervals of time
Re-assessing the data
Investigating in depth some new economic structures

14. Revision policy
Countries are encouraged to develop a well-designed, carefully managed and coordinated with other areas of statistics revision policy for DTS
Essential features of a well-established revision policy
Predetermine schedule
Reasonable stability from year to year
Openness
Advance notice of reasons and effects
Easy access of users to sufficiently long time series of revised data
Adequate documentation of revisions included in the statistical publications and databases

15. Dissemination of metadata
Provision of an adequate metadata and quality assessment of DTS is as important to users as provision of data
Countries are encouraged to develop and disseminate metadata on DTS
Metadata components
Data coverage, periodicity and timeliness
Access by the public
Integrity of disseminated data
Data quality
Summary methodology
Dissemination formats

16. International reporting – Annual data

17. International reporting – Quarterly data

18. International reporting – Monthly data

19. Thank You