Public Review Announcement for SDMX Data Structure Definitions for International Merchandise Trade Statistics (SDMX-IMTS)

An inter-agency working group comprising of Eurostat, the International Trade Centre (ITC), the Organization for Economic Cooperation and Development (OECD), the United Nations Statistics Division (UNSD), and the United Nations Conference on Trade and Development (UNCTAD) has been established to support the implementation of SDMX standards in International Merchandise Trade Statistics (IMTS).

The working group, which develops these new standards, seeks to specify uniform structures, concept definitions and code lists for IMTS data and metadata which comply with the latest version of the SDMX standard (2.1), and which follow the latest recommendations for IMTS (IMTS 2010) since 2013. To the extent possible, SDMX-IMTS reuses concepts and code lists that have been already agreed internationally. The draft Data Structure Definition (DSD) for SDMX-IMTS is available at http://comtrade.un.org/sdmx.

Global online consultation has been initiated between May and June 2015 to receive broad input on the proposed DSD for IMTS. All details of the consultation, including how to access the questionnaire and what is expected of the review of the DSD can be found in the Information Note. For any other inquiries, please contact tradestat@un.org.

Guidelines on Modelling a Statistical Domain for Data Exchange in SDMX

This new guideline outlines general principles on how to design and create SDMX artefacts in a statistical domain, following a step-by-step approach to design based on the SDMX information model, while also complementing the existing guidelines on Data Structure Definitions and Code Lists. A poster highlighting the various steps of the process is annexed to the document.

The document includes how to determine the number of Data Structure Definitions (DSDs) for a subject-matter domain, and recommends that this decision should come after the discussion on all parameters of the data collection exercise.

VTL 1.0 – Validation and Transformation Language

VTL is a standard language for defining validation and transformation rules (set of operators, their syntax and semantics) for any kind of statistical data. VTL builds on the Transformation section of the SDMX information model, by taking the common parts of GSIM, SDMX and DDI as for the representation of concepts and data.

The assumption is that such a logical formalization of validation and transformation rules will provide a “technology-neutral” expression at business level of the processing taking place, against which various implementations and specific programming languages can be mapped.

The specifications for exchanging VTL validation rules in SDMX messages, for storing rules and for requesting validation rules from web services will be provided in a specific update to the SDMX Technical Standards on which the SDMX Technical Working Group is working on.

The VTL 1.0 package includes:

  1. Part 1, highlighting the main characteristics of VTL, its core assumptions and the information model the language is based on;
  2. Part 2, containing the full library of operators ordered by category, including examples; this first version can support validation and basic compilation needs. Future versions, whose design is already in progress, will include more features related to transformation of data;
  3. EBNF notation (Extended Backus-Naur Form) which is the technical notation to be used as a test bed for all the examples throughout the document.

Download the complete VTL 1.0 package (part 1, part 2, EBNF)

Please send your comments to the SDMX Technical Working Group (TWG) at twg@sdmx.org. Each email message should contain only a limited set of numbered – and possibly homogeneous – comments and should contain the elements indicated in the attached comment log.

Posted on 3 March 2015

Public Review Announcement for the new version of the SDMX RESTful API Specification

The SDMX Technical Working Group (TWG) has prepared a version v1.1.0 of the SDMX RESTful web services API specification for public review. The review period extends until 30 June 2015.  Feedback is welcome.

Version v1.1.0 contains two new features, two improvements to existing features and one bug fix. Furthermore, the documentation has been improved with the addition of a tutorial, a cheat sheet and new sections about best practices for data providers and data consumers.

All changes can be viewed on Github at the following location: https://github.com/sdmx-twg/sdmx-rest. The use of Github significantly eases the work of comparing the changes with the previous releases of the specification.

– Complete list of releases:
https://github.com/sdmx-twg/sdmx-rest/releases

– Complete list of changes since the previous release v1.0.2:
https://github.com/sdmx-twg/sdmx-rest/compare/v1.0.2…master

– Overview of new features, improvements and bug fixes in the new version:
https://github.com/sdmx-twg/sdmx-rest/issues?q=is%3Aissue+milestone%3Av1.1.0+is%3Aclosed

Please send your comments to the SDMX Technical Working Group (SDMX-TWG) at twg@sdmx.org, using the attached comment log. Alternatively, changes can be proposed by forking the Github repository and sending pull requests.

Posted on 26 February 2015