8.9 Requirements Concerning the Uncertainty
127
Key comparisons:
calibration laboratories
Name of the laboratory
Code of the laboratory
Code of the laboratory
Proficiency tests:
expert laboratories
Interlaboratory
comparisons:
research laboratories
x±U
x±U
x±U
c [mg/kg]
c [mg/kg]
c [mg/kg]
Fig. 8.2 Consistency of results within various kinds of laboratories
NOTE: In the key comparisons, organized by the International Bureau of
Weights and Measures, participants are expected to submit their identification, which is publicly known. In proficiency testing or in inter-laboratory
comparisons, the organizers ensure the confidentiality of identification of the
laboratories.
The requirement to evaluate the uncertainty has significantly changed the approach
of chemists to understanding of the quality of the results. Although it became common
practice, one can still hear the opinion that the determination of uncertainty has been
unnecessarily exaggerated. Some analysts still believe that the effort directed at the
evaluation of uncertainty is unnecessary and that it is done because it is required
in the standards and by accreditation. Often an opinion can be encountered that the
determination of the uncertainty is very difficult and complicated: “We must do it,
so we do it.” The requirement to provide the result with an uncertainty assigned
to it is, in fact, very clearly articulated in the ISO/IEC 17025. It is worth noting,
however, that the high expectation to determine the uncertainty enforces the necessity
to conduct a detailed insight view into the used measuring procedure and critical
evaluation of factors influencing the quality of the result. Submitting the result with
127
Key comparisons:
calibration laboratories
Name of the laboratory
Code of the laboratory
Code of the laboratory
Proficiency tests:
expert laboratories
Interlaboratory
comparisons:
research laboratories
x±U
x±U
x±U
c [mg/kg]
c [mg/kg]
c [mg/kg]
Fig. 8.2 Consistency of results within various kinds of laboratories
NOTE: In the key comparisons, organized by the International Bureau of
Weights and Measures, participants are expected to submit their identification, which is publicly known. In proficiency testing or in inter-laboratory
comparisons, the organizers ensure the confidentiality of identification of the
laboratories.
The requirement to evaluate the uncertainty has significantly changed the approach
of chemists to understanding of the quality of the results. Although it became common
practice, one can still hear the opinion that the determination of uncertainty has been
unnecessarily exaggerated. Some analysts still believe that the effort directed at the
evaluation of uncertainty is unnecessary and that it is done because it is required
in the standards and by accreditation. Often an opinion can be encountered that the
determination of the uncertainty is very difficult and complicated: “We must do it,
so we do it.” The requirement to provide the result with an uncertainty assigned
to it is, in fact, very clearly articulated in the ISO/IEC 17025. It is worth noting,
however, that the high expectation to determine the uncertainty enforces the necessity
to conduct a detailed insight view into the used measuring procedure and critical
evaluation of factors influencing the quality of the result. Submitting the result with