The statistical evaluation of the interlaboratory comparison is defined in ISO 13528 and ISO 5725-2.
148 testing laboratories from 35 countries all over the world participated in 66 individual test methods in the last proficiency test OFI-pts2020.
| Argentina | Malaysia |
| Austria | Marocco |
| Belgium | Norway |
| Bulgaria | Poland |
| Canada | Portugal |
| China | Romania |
| Croatia | Slovakia |
| Czech Republic | Slovenia |
| Finland | South Korea |
| France | Sri Lanka |
| Germany | Spain |
| Great Britain | Sweden |
| Greece | Switzerland |
| Hungary | The Netherlands |
| Israel | Turkey |
| Italy | Thailand |
| Japan | USA |
| Lativia |
Evaluation parameter
Outlier according to Grubbs’ test
Outlier according to Cochran’s test
z-score
Youden-Plot (Scatter diagram)
