Is the z score sufficient to assess participants’ performance in proficiency testing? The hidden corrective action
Proficiency testing providers, accreditation bodies and testing laboratories should be aware that a laboratory participating in a proficiency testing round might have reported a biased result despite a satisfactory performance indication in an assessment using uniquely the z score. A complementary performance evaluation, based on the z score and the assessment of the measurement uncertainty, is therefore highly recommended.
This work presents an intuitive graphical tool (the Naji2 plot) that combines z and zeta scores together with the reported measurement uncertainties. This tool allows a comprehensive assessment of the laboratory performance and enables to identify the need for corrective actions. The concerned laboratory should then perform a root cause analysis and investigate their bias and/or their measurement uncertainty evaluation.
CORDEIRO RAPOSO Fernando;
EMONS Hendrik;
ROBOUCH Piotr;
2022-12-12
SPRINGER
JRC125147
0949-1775 (online),
https://doi.org/10.1007/s00769-022-01496-w,
https://publications.jrc.ec.europa.eu/repository/handle/JRC125147,
10.1007/s00769-022-01496-w (online),
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