FAQ: Frequently Asked Questions

What is an interlaboratory test, what is a proficiency test?

An interlaboratory test is generally understood to mean that a specific measurement or testing task is performed independently by a group of laboratories. The analysis can be used to assess test methods, participant performance or to characterise samples or materials.

An interlaboratory test to evaluate the performance of participants is referred to as a proficiency test. The test result of a participant is determined according to previously established criteria by comparing the results of the entire participant field. The provider of the EQAS shall produce an anonymous report on the performance assessment of all participants. Participants in our proficiency tests receive a certificate. It is therefore a quality assurance measure in the respective field of activity.

We would like to explain a proficiency test to you using a short example: The task of the proficiency test is to determine the indentation hardness with a durometer, characteristic value Shore-D according to DIN EN ISO 868. As a provider of interlaboratory comparisons, we provide all participants with similar samples and allow the participants an adequate period of time to carry out the test(s). The participants submit their measurement results to our online portal. The results are then analysed and evaluated using appropriate statistical methods. Testing laboratories accredited according to DIN EN ISO/IEC 17025 must regularly take part in proficiency tests.

The subject of a proficiency test is the sample, data series or other information used to perform the proficiency test. In most of our proficiency tests, you will receive samples that you characterize in standardized test procedures in order to assess your suitability or capability for this method.

When does participation in one of the trials become binding?

After you have submitted your request by selection in our online catalogue, we will provide you with a non-binding offer with complete cost information and reserve your participation in the EQAS. The offer includes quantity discounts and the costs for express distribution and sample protection. With your confirmation of our offer, your interest in participating in the round robin test becomes binding.

In order to make the proficiency test a meaningful instrument of quality assurance, there are lower limits for the size of the participant field. As a rule, a reliable statistical evaluation can only be carried out with the participation of a sufficient number of participants. Even if this case does not occur very frequently with us, we therefore reserve the right to cancel an experiment if there are doubts about the significance or quality of the evaluation. In these cases, the participants are contacted and a solution is sought that meets all interests. Our order confirmation will include those proficiency tests which will take place to the planned extent and on the scheduled date.

Does the DIR charge cancellation fees?

No.

How does the online catalogue work?

The navigation sidebar helps you to select your proficiency tests. By clicking on the navigation fields, which are displayed as headings, the catalogue automatically moves to the selected position. It is also possible to display the complete list. If you are only interested in certain areas, simply use the filter elements and our aptitude tests will be displayed in the corresponding field. You can also browse our offer sorted by process or product groups. Both groups contain the complete program. If a suitability test has already been selected in the process group, the same suitability test is automatically marked in the product group and vice versa. You can view and deselect your selected suitability tests under the navigation field «Selected articles».

Who else is involved in the interlaboratory test series?

We engage subcontractors for certain tasks within the organisation of the interlaboratory comparisons. A subcontractor is the organisation or person selected by the EQAS provider to carry out activities that affect the quality of a proficiency testing scheme. Various aspects of the proficiency testing scheme may be subcontracted on a temporary basis. In the case of subcontracting, this will be done to a competent subcontractor.

What does repeatability and reproducibility conditions mean?

The generation of test results is inevitably associated with limited reproducibility. Depending on the prevailing or applied boundary conditions, the scatter of test results may vary. The following explanations are based on ideally homogeneous samples. Non-destructive tests therefore represent the limit case, since a measured value can be reproduced exactly as often as required.

The narrowest distribution of test results can be expected under so-called repeatability conditions. This is an inspection situation in which a test is performed by the same person with the same equipment and identical operations within a short period of time between repetitions.

If a test is carried out by different persons on different equipment and with a longer period of time between the executions, which can cause a relevant change in the environmental conditions, this is referred to as reproducibility conditions.

Unless otherwise specified, the participating laboratories shall perform the specified number of test series in their laboratory routine under repeatability conditions.

If you want to use different persons or different test devices in a proficiency test, we expressly recommend separate participations in the proficiency test. In this case, you will receive additional laboratory codes in order to be able to assign your test results.