To investigate properties and to compare and validate several alternative statistical approaches, simulation studies play a key role. They are a very important instrument to create knowledge for the guidance documents. Some ‘loose’ rules will help to improve design, conduct, analysis and reporting of meaningful simulation studies. That will help to increase both transparency and practical relevance of STRATOS research. Furthermore, suitable rules will (partly) harmonize design issues across topic groups and improve investigations when statistical issues relevant to two or more TGs need to be simultaneously addressed.