AbstractThe organisation of a test performance study (TPS) involves different steps that are mostly sequential, but some may be conducted simultaneously. This chapter details the following: the steps regarding the selection of the tests to be validated; the selection of the laboratories to participate in the TPS; the preparation of the materials and the dispatch of the samples; and the completion of the TPS (including the collection and analysis of the TPS results). The reader will be able to get the detailed information on how to define and plan timeline of the TPS, the appropriate number of samples (including replicates) and of laboratories that should be included in the TPS to ensure an appropriate statistical analysis, and how to perform basic analyses of the obtained data. In addition, this chapter covers the most important critical points which can endanger successful TPS organization providing the future TPS organisers in the field of plant health (but also in other similar fields) with the possibility to identify them in advance and carry-out successful TPS.