The verification and validation of methods consist in evaluating the precision, the analytical range, the accuracy, the trueness and the detection limit, if appropriate. These measurements must follow a standardized protocol and the obtained results must be compared to defined quality criteria. Each chapter includes, the purpose, the material used, the operating procedures, the collection of results, the calculation and is illustrated by an example. This document aims at simplifying, standardizing and optimizing the evaluation in order to allow a comparison between laboratories and to facilitate method assessment.