sentences:  They should also be reliable and valid (including responsive to underlying change) and the structure of the scale (whether it possesses a single or multiple domains) should have been thoroughly tested using appropriate methodology in order to justify the use of scale or summary scores.The validation of the PRO measures should incorporate not only short-term but also long-term success in order to be able to reflect sustainability of interventions.Classic examples of such tools and methods are noted in commonly used oncology tools, such as FACT or EORTC tools.