Physical activity (PA) is essential in maintaining optimal health in chronic diseases, including COPD.More physically active patients have less hospital admissions and better survival. Validated physicalactivity monitors have become available in recent years, and together with patient report of symptomsand distress of physical (in)activity, this may form a potent new Patient Reported Outcome (PRO) in COPD.In response to the IMI-call this consortium will develop and validate two PRO’s. In phase 1, items forthe PRO will be generated based on input from an updated literature survey, expert opinion and patients. One PRO investigates PA on a daily basis, using a user friendly interface. This allows investigating the impact of exacerbations and the dynamics of improvement after initiating treatment. A second PRO is used during clinical trial visits. A unique feature of the PRO’s is that they will include unobtrusive physical activity monitoring. Validity, reproducibility, responsiveness and minimallyclinically meaningful difference of the PRO’s will be investigated. The new PRO’s will be put in thecontext of other, more conventional outcomes. using path-analysis and structural equational modeling.Development will be in compliance to the guidelines of the FDA and in collaboration with EMEA.Iii phase 2 the PRO’s will be used in 3 large multi-center clinical trials. These trials will contribute tothe validity and health economic value of the PRO’s. They tackle contemporary questions in COPDcare, including pharmacotherapy, PA counseling and pulmonary rehabilitation.The consortium is well equipped to develop PRO’s. It includes academic centers with a solid reputationin COPD research, centers with expertise in epidemiology, experts in conducting systematic reviews,PRO-methodology and statistics. Patient associations are in the core of the consortium. A SME willdevelop patient material in various languages.