Our reports strictly comply with the requirements of the ISO/IEC 17043 standard. To compliance ISO/IEC 17043 requirements our final reports have structure defined.
Furthermore, they have been carefully prepared to be clear, professional and show the robustness of the statistical method used.
The objective of proficiency testing is to perform an evaluation of laboratory performance by comparing results. For the analysis of the data, assumptions are taken into account to draw consistent conclusions from the results.
BASED ON 💻
The statistical treatment was performed according to ISO 13528:2015. “Statistical methods for use in proficiency testing by interlaboratory comparisons”.
Just before the statistical treatment, a exploratory data analysis is performed according to the following criteria:
- Traceability of the provided result (checking of the sample identification number);
- Integrity (through scheduled Audit Trail logging);
- Visual (expression of the result, data input error);
- Technical (According to studied standard)
- Statistical analysis (hypothesis testing, observed distributions, outliers detection);
We used the Algorithm A described in Appendix C of ISO 13528 to obtain robust estimators of the mean and standard deviation. This robust mean will be the reference value used to calculate the score of the laboratories.
Based on the z-score |z|, the following classification of laboratories can be assigned:
- |z| > 3 ⟹ D
- 2 < = |z| < 3 ⟹ C
- 1 < = |z| < 2 ⟹ B
- 0 < = |z| < 1 ⟹ A
It is usually added the symbol “+” or “-” to this label depending on whether the z-score is positive or negative respectively.
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