, Volume 18, Issue 5, pp 419–423 | Cite as

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

How Meaningful is it?
Current Opinion


It is generally believed that small differences in health-related quality of life (HR-QOL) may be statistically significant yet clinically unimportant. The concept of the minimal clinically meaningful difference (MCID) has been proposed to refer to the smallest difference in a HR-QOL score that is considered to be worthwhile or clinically important.

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).


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Copyright information

© Adis International Limited 2000

Authors and Affiliations

  1. 1.Division of General Internal Medicine and Health Services ResearchUCLA Department of MedicineLos AngelesUSA
  2. 2.RANDSanta MonicaUSA
  3. 3.Amgen Inc.Thousand OaksUSA

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