In January – February 2023, a ring test organized by EiraNet Grain Network took place. Both Latvian and Estonian companies participated in it. Some non-grain network labs/instruments also participated.
3 wheat, 3 barley and 3 rape samples were offered in the ring test.
The reference results were obtained in the laboratory of SIA “Eira Lab”.
| Commodity | Parameter | Reference method | sR for stats evaluation |
|---|---|---|---|
| Wheat | EN ISO 712:2009 | 0,14% | |
| EN ISO 20483 | 0,20% | ||
| ISO 21415-1 | 0,70% | ||
| Master instrument results | 1,14 ml | ||
| Master instrument results | 0,54% | ||
| ISO 7971-3 | 0,29 kg/hl | ||
| Barley | EN ISO 712:2009 | 0,17% | |
| EN ISO 20483 | 0,20% | ||
| Master instrument results | 0,38% | ||
| ISO 7971-3 | 0,34 kg/hl | ||
| Rapeseed | ISO 665:2000 | 0,16% | |
| ISO 659:2009 | 0,55% |
The “Parameter” column of the table contains links to the relevant results and graphs. The link will open in a new page, the results table is initially organized by lab code, but you can change the layout to your liking. For each sample, the difference to the reference value is given, as well as the statistical evaluation of this difference as a Z-factor. All results with Z-factors less than 2 are considered good. If Z>2 – it is colored yellow, if Z>3 – it is colored red. In these cases, it would be advisable to look for reasons why these results are different. The last column “Z-fact-Median (ABS)” is the median value of the Z-fact, which gives an approximate overall assessment of your laboratory. It has the same criteria as the Z-factor score. “sR” is the standard deviation of the reproducibility of the results, which we simply call “standard error”. Z-factor is a performance criterion for the participating laboratories (or instruments). It is calculated by dividing the difference (lab.res.-ref.res.) by the sR.
Protein values in dry matter were compared for Wheat and Barley, with a nitrogen factor of N=5.7 and N=6.25, respectively.
For Wheat Gluten “As Is” values (ISO 21415-1) were compared.
The Starch values in dry matter were compared for Wheat and Barley.
For Wheat and Barley, the Testweight values “As Is” were compared, the unit of measure – kg/hl.
Oil in dry matter values were compared for Canola.
Results submitted with a different moisture base and/or a different nitrogen factor or in other units were recalculated accordingly.