WMO/GAW Glossary of QA/QC-Related Terminology

The evaluation and characterisation of data obtained from measurements made within WMO/GAW Programme involve a number of statistical parameters and specific terms to characterise data quality. At present, several of these terms (e.g. precision) are frequently used with different meaning by different people. Efforts for standardization have been made in the past, involving contributions from a number of international organizations, and are coordinated under the umbrella of ISO.

With the aim of ensuring the comparability and compatibility of measurements, the GAW Implementation Plan recommends adoption and use of internationally accepted methods and vocabulary to deal with measurement uncertainty as outlined in various ISO/BIPM publications. Since each term should have the same meaning for all of its users, efforts are called for to familiarize all individuals involved in the WMO/GAW Programme and the associated scientific community with the relevant terminology. GAW members are strongly encouraged to use these terms in their own publications and to suggest their use when reviewing manuscripts of others.

The glossary below is largely based on the 3rd edition of "International vocabulary of metrology — Basic and general concepts and associated terms (VIM)", which is freely available through the Joint Committee for Guides in Metrology. It includes now a number of terms that were - to the knowledge of the editors - not previously defined in ISO/BIPM publications and that can now be referenced directly to this one authoritative source. The number of terms defined in the latest edition of the VIM is overwhelming at first encounter, and the editors have tried to select those that are deemed most relevant for WMO/GAW. Moreover, in some cases notes/and or examples given in the VIM have been removed, while additional notes and/or examples have been added with respect to the specific requirements of the WMO/GAW Programme. If you find that terms are missing from this glossary, please contact one of the editors.

The 3rd edition of the VIM, while freely available on the internet, is copy-righted material. The editors of this WMO/GAW glossary are therefore grateful to BIPM and the JCGM for a generous handling of copyright matters and are pleased to insert the following acknowledgment: "Extracts from the International Vocabulary of Metrology – Basic and General Concepts and Associated Terms (VIM), 3rd edition, JCGM 200:2008 (www.bipm.org/en/publications/guides/vim.html) are published with permission of the Director of the International Bureau of Weights and Measures (BIPM), in his function as Chairman of the JCGM."