Dr. Dennis Revicki, Sr Vice President and Scientific Director, Center for Health Outcomes Research, is a psychometrician with over 25 yrs experience in developing and validating patient reported outcome (PRO) measures and in the analysis and interpretation of PRO data from clinical trials. Evaluating the responsiveness and providing interpretation guidance for PRO measures are critical for understanding these endpoints in clinical trials. This presentation will discuss methods for evaluating responisveness and for determining the clinical significance of changes or differences in PRO measures. There are uncertainties about the best approaches for identifying values for interpreting clinical significance of differences between group mean changes in PRO measures and for responder analyses. This presentation will provide guidance on the best methods for determining clinical significance.