A harmonized approach for the validation of analytical methods based on accuracy profile was introduced by a SFSTP commission on the validation of analytical procedure. This fourth and last document aims at illustrating this methodology and the statistics used. Therefore the validation of real case methods are proposed such as methods for the quality control of drugs, for the quantitation of impurities in drug substances, for bioanalysis or for the determination of nutriments. Furthermore, different types of analytical methods are used in order to demonstrate the applicability of the proposed approach to a wide range of methods such as liquid chromatography (LC-UV, LC-MS), spectrophotometry or ELISA.