In the following, the discussions held in the 4 “technical” working groups of the PERAS workshop are summarized. Formally, this compilation is based on the reports presented by the 4 workgroup rapporteurs, as well as on the overall summary presented by the workshop rapporteur. The information provided here mirrors the agreements made in the 4 groups. In those cases where no agreement could be achieved, the differing opinions are presented. Methodological and detailed technical recommendations for the design and performance of TME studies are given in Appendix 2.