The importance of “precise” test values and their verification is growing in every industry throughout the world. Interlaboratory studies constitute a basis for this. The high expenses and mathematical work required to carry out proper interlaboratory studies are frequently considered reasons not to conduct such studies. This makes it all the more important to emphasize the various advantages of an accurate interlaboratory study. In addition to providing precision data for the test method, it is also possible to carry out laboratory evaluations, which is important for accredited test laboratories. Furthermore, existing test methods can be optimized, reference material can be obtained, and test methods can be compared. Optimized test instructions can also be generated using the findings and precision data. These advantages will be described in detail by means of examples below.