The Concept of Clinically Meaningful Difference in Health-Related Quality-of-Life Research

However, there is danger in oversimplification in asking the question: what is the MCID on this HR-QOL instrument? We argue that the attempt to define a single MCID is problematic for a number of reasons and recommend caution in the search for the MCID holy grail. Specifically, absolute thresholds are suspect because they ignore the cost or resources required to produce a change in HR-QOL. In addition, there are several practical problems in estimating the MCID, including: (i) the estimated magnitude varies depending on the distributional index and the external standard or anchor; (ii) the amount of change might depend on the direction of change; and (iii) the meaning of change depends on where you start (baseline value).