Practical guidance for organizing small interlaboratory comparisons


This article brings practical guidance for organization of interlaboratory comparisons (ILCs) with small number of participants (n = 2–7) that is not arranged by a proficiency testing provider. The methodological guideline aims to provide practical advices in following technical requirements of small ILC organization: design of a scheme, preparation, packaging and distribution of ILC test items, instructions for participants, evaluation of results and participants’ performance, and participation report. The determination of the assigned value and standard deviation for proficiency assessment is also covered and is accompanied by the practical example where the assigned value is established using order statistics.

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This work was supported by the Ministry of Education, Youth and Sports of the Czech Republic (LTV 20008) and the Office for Standards, Metrology and Testing (PRM 2019 VII/6/19).

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Correspondence to David Milde.

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DM and EK declare no conflict of interest. AN works for an accredited PT provider.

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Milde, D., Klokočníková, E. & Nižnanská, A. Practical guidance for organizing small interlaboratory comparisons. Accred Qual Assur 26, 17–22 (2021).

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  • Small interlaboratory comparison
  • Guide
  • Organization
  • Order statistics