Comparative study of three approaches of measurements uncertainties evaluation GUM, GUM S1 and GLOBALE

One of the missions of the Office National de Sécurité Sanitaire des Produits Alimentaires (ONSSA) is to protect consumers. In this context, the reliability of food product control is crucial.

Various analyses carried out by the ONSSA laboratory allow us to assess the conformity of food products to current standards.

The performance of an analysis relies to a large extent on equipment, made up of: (i) measuring equipment, i.e. the device used to take a measurement and give the value of a quantity, (ii) analysis equipment, which provides a result, and (iii) intermediate equipment, which takes part in obtaining it.

Generally speaking, metrology is used to monitor the measurement process and ensure that measuring instruments are working properly. It ensures that measurements are taken to enable tests to be carried out in compliance with standards and requirements.

In order to optimize the interpretation of measurement results, it is essential to control the uncertainties associated with them. Several approaches can be used to estimate these uncertainties.

This is the background to the work carried out by the metrology and quality section of the Marrakech Regional Laboratory for Analysis and Research. This department is committed to continuous improvement, and is part of a quality management system drawn up by ONSSA.

This article presents a comparative study of the most widely used approaches to uncertainty assessment: GUM (Guide to the Expression of Uncertainty in Measurement), GUM S1 (Supplement 1 to GUM) and global, and how to take advantage of the complementarity of these approaches to meet measurement quality and reliability requirements.