The objective of this project was to give guidance for understanding the performance and reliability of a classification rule, when applied to data generated by the transformation/dissolution (T/D) protocol. The classification of sparingly soluble metal compounds is based on ecotoxicity reference values and on the measured concentrations of metal ions of experiments performed according to the T/D protocol and the standard operating procedure. The assessment was conducted by Dr. Reinhard Meister, TFH Berlin - University of Applied Sciences. The Nordic project group on Classification and Labelling under the Nordic Chemicals Group has been responsible for the project and the report is written by Reinhard Meister and Jonas Falck. The project was financed by The Nordic Council of Ministers. The probabilistic assessment presented in this report, apart from being issued by the Nordic Council of Ministers, is also intended for publication by the OECD as part of an OECD Phase 2 report concerning the validation of the transformation/dissolution (T/D) protocol (Annex 10 of /1/).