General Paper

Accreditation and Quality Assurance

, Volume 6, Issue 7, pp 290-294

Uncertainty calculations in the certification of reference materials 4. Characterisation and certification

  • Adriaan M. H. van der VeenAffiliated withNederlands Meetinstituut, Schoemakerstraat 97, 2600 AR Delft, The Netherlands e-mail: avdveen@nmi.nl Tel.: +31-15-2691 733 Fax: +31-15-2612 971
  • , Thomas P. J. LinsingerAffiliated withEuropean Commission, Joint Research Centre, Institute for Reference Materials and Measurements, Retieseweg, 2440 Geel, Belgium e-mail: Jean.Pauwels@irmm.jrc.be Tel.: +32-14-571 722 Fax: +32-14-590 406
  • , Heinz SchimmelAffiliated withEuropean Commission, Joint Research Centre, Institute for Reference Materials and Measurements, Retieseweg, 2440 Geel, Belgium e-mail: Jean.Pauwels@irmm.jrc.be Tel.: +32-14-571 722 Fax: +32-14-590 406
  • , Andree LambertyAffiliated withEuropean Commission, Joint Research Centre, Institute for Reference Materials and Measurements, Retieseweg, 2440 Geel, Belgium e-mail: Jean.Pauwels@irmm.jrc.be Tel.: +32-14-571 722 Fax: +32-14-590 406
  • , Jean PauwelsAffiliated withEuropean Commission, Joint Research Centre, Institute for Reference Materials and Measurements, Retieseweg, 2440 Geel, Belgium e-mail: Jean.Pauwels@irmm.jrc.be Tel.: +32-14-571 722 Fax: +32-14-590 406

Rent the article at a discount

Rent now

* Final gross prices may vary according to local VAT.

Get Access

Abstract 

The main objective of the certification of a reference material is to determine its property values including their uncertainty. In the previous parts of this series, the basis for the evaluation of measurement uncertainty of the property values has been examined, including the conversion of homogeneity and stability study data into standard uncertainties. In this final part, the determination of the property values and the modelling of the certification process is discussed. It is noted that the characterisation of a reference material can be modelled in some cases using analysis of variance statistics, but a more generally applicable model can be developed based on χ2-fitting. Furthermore, it is concluded that there is an advantage in using absolute standard uncertainties instead of relative ones when modelling the certification process.

Keywords CRMs Measurement uncertainty Homogeneity study Stability study Certification