Estimation of uncertainties and the use of reference materials
Free online course
In this course, you will learn the basics why measurement uncertainties are important and how you can estimate them. You will learn the role and importance of reference materials and how you can best select and use them. Our interactive course will be complemented by practical exercises where you can apply and test your newly acquired knowledge. You will be able to follow 8 modules:
- Estimation of measurement uncertainty – This module explains what measurements uncertainty is and why is needed. You will learn how to estimate measurements uncertainty and will be get more details on the quantification procedure and whether it is a combination of uncertainty sources. At the end we show two options: the so-called bottom-up approach and the so-called top-down approach (use of validation data).
- Use of CRMs to prove laboratory and method performance – This module provides the tools to understand how to make use of the added value of certified reference materials (CRMs) to prove laboratory and/or method performance.
- Making the best use of RMs –This module presents how to get the best use out of reference materials and you will learn what sources of information are available.
- Use of CRMs in method validation - In this module, will be explained how to validate a new method and how to estimate the measurement uncertainty of its results.
- Commutability of reference materials – After being acquainted with the validation of a new method and how to estimate the uncertainty of its measurements, in this module focus will be on the commutability of reference materials.
- Selection of reference materials – In this module will be presented all the steps to consider when selecting a reference material.
- Traceability of measurement results - In this module, will be explained the metrological traceability and its role for the comparability of measurement results. Furthermore will be described how certified reference materials or CRMs can be used to help you to make your results traceable.
- The wrap-up - This last module provides an example of how this course can guide you through the processes in your laboratory practice.
This course is intended for practitioners working in laboratories that need to apply reference materials for statistical quality control, method validation and calibration and who need to assess measurement uncertainties on customer’s demand or as requirement of the ISO/IEC 17025 standard. It can also be useful for ISO/IEC 17025 auditors who need to assess the estimation of measurement uncertainties and the correct application of certified reference materials.
Join freely the course wherever you are, whenever you want, and whatever device you want to use!
Useful links
Much information on reference materials is available on the internet. There are not only lists or searchable catalogues of available reference materials, but also several documents on the selection and use of reference materials. This page gives an overview over available databases and documents, but does not claim to be exhaustive. These websites are not updated with the same frequency. In case of specific CRMs, we therefore recommend checking the website of the producer for availability and additional information.
- COMAR: This used to be the most comprehensive database worldwide containing approximately 10 000 CRMs. After a major revamp, it is currently filled again with CRMs.
- Database of the AOAC: Technical Division for Reference Materials. Mainly food reference materials.
- GeoReM (Geological and Environmental Reference Materials): Database of reference materials and isotopic standards of geochemical and mineralogical interest. It contains about 2200 different materials
National Metrology Institutes and their designated institutes which have signed the Comité International des Poids et Mesures - Mutual Recognition Arrangement (CIPM-MRA) aim at providing measurement tools at highest standard for disseminating metrological traceability. Several of these signatories also produce certified reference materials.
- International Atomic Energy Agency (IAEA), UN
- Bundesanstalt für Materialforschung und – Prüfung (BAM), DE
- National Metrology Institute of Japan (NMIJ), JP
- National Research Council of Canada (NRCC), CA
- National Sharing Platform for Reference Materials (CNRM), CN
- Instituto Nacional de Metrologia, Normalização e Qualidade Industrial (INMETRO), BR
- Korea Research Institute of Standards and Science, KR.
- Centro Nacional de Metrología (CENAM), MX
- National Institute of Standards and Technology (NIST), US
- ISO 33403: Reference materials — Requirements and recommendations for use. This standard replaced ISO Guide 33 in 2024
- The Use of Reference Materials: A Tutorial (2001): Geostandards and Geoanalytical Research, Volume 25, pp. 7-22, Author: J. S. Kane
- EA-4/14-Selection and Use of Reference Materials (2003): This document was prepared by the European Co-operation for accreditation (EA), the European Federation of National Associations of Measurement, Testing and Analytical Laboratories (Eurolab) and Eurachem, a network of organisations in Europe having the objective of establishing a system for the international traceability of chemical measurements and the promotion of good quality practices.