This document provides guidance to study organizers involved in designing, executing and evaluating collaborative studies for multi-analyte methods developed by the various working groups of the CEN/TC 327 “Animal feeding stuffs: Methods of sampling and analysis”. The main goal of such studies is to determine the reproducibility standard deviations for the analytes investigated in the selected matrices. They are calculated from the repeatability and the between-laboratory standard deviations determined from the study data. An additional goal may be the determination of the trueness (whenever possible).