The EXACT-PRO Initiative (EXAcerbations of Chronic Pulmonary Disease Tool – Patient-Reported Outcome) brought together clinical, research, methodology, and regulatory experts to develop a new patient-reported outcome (PRO) instrument to standardize the symptomatic assessment of exacerbations of COPD for evaluating frequency, severity, and duration of exacerbations in clinical trials of COPD (“EXACT”, 14-items PRO).