The statistical evaluation of the interlaboratory comparison is defined in ISO 13528 and ISO 5725-2.

156 testing laboratories from 37 countries all over the world participated in 64 individual test methods in the last proficiency test OFI-pts2018.

Austria Norway
Bangladesh Poland
Belgium Portugal
Brasil Romania
China Saudi Arabia
Colombia Slovakia
Costa Rica Slovenia
Croatia South Korea
Czech Republic Spain
France Sri Lanka
Germany Sweden
Great Britain Switzerland
Greece Thailand
Hungary The Netherlands
Iran Turkey
Italy United Arab Emirates
Japan USA
Latvia


Evaluation parameter

Outlier according to Grubbs’ test
Outlier according to Cochran’s test
z-score
Youden-Plot (Scatter diagram)