Research Article| Volume 56, ISSUE 7, P618-621, July 2003

Download started.


The MDP75

A new approach in the determination of the minimal clinically meaningful difference in a scale or a questionnaire


      Background and Objective: The MDP75 (Minimal Difference Perceived 75% of the time) is the difference in the global score from a scale or a questionnaire which, 75% of the time, leads to the higher score being spontaneously attributed by patients or clinicians to the most severe situation. This may be considered as a “minimal clinically perceptible difference” because the proportion of “consistent” choices only exceeds the proportion that could be observed “by chance” by 50%.
      Methods: The MDP75 can be estimated through a comparison of two groups of items (group A and group B) randomly selected from the instrument, using a sample of subjects. A logistic regression is then used that relates the choice of A or B to the difference: score(A) – score(B).
      Results: Data were collected on a depression scale, the HDRS. Three clinicians classified 300 pairs of situations. The MDP75 obtained was 2.7, with a 95% confidence interval of [1.9, 4.1].
      Conclusion: It can be noted that this value is consistent with expert opinion (3 or 4). Nevertheless, in view of the small number of clinicians involved in the data collection phase, further studies are required to confirm this result.


      To read this article in full you will need to make a payment

      Purchase one-time access:

      Academic & Personal: 24 hour online accessCorporate R&D Professionals: 24 hour online access
      One-time access price info
      • For academic or personal research use, select 'Academic and Personal'
      • For corporate R&D use, select 'Corporate R&D Professionals'


      Subscribe to Journal of Clinical Epidemiology
      Already a print subscriber? Claim online access
      Already an online subscriber? Sign in
      Institutional Access: Sign in to ScienceDirect


        • Norman G.R.
        • Gwadry Sridar F.
        • Guyatt G.H.
        • Walter S.D.
        Relation of distribution- and anchor-based approaches in interpretation of changes in health-related quality of life.
        Med Care. 2001; 39: 1039-1047
        • Hamilton M.
        A rating scale for depression.
        J Neurol Neurosurg Psychiatry. 1960; 23: 56-62
      1. R [computer program]. Version 1.4.1.;2002.

      2. SAS [computer program], version 8.2. SAS institute Inc, Cary, NC2001
        • Drummond M.F.
        • O'Brien B.J.
        • Stoddart G.L.
        • Torrance G.W.
        Methods for the economic evaluation of health care programs.
        2nd ed. Oxford University Press, Oxford1997
        • Montgomery S.A.
        Clinically relevant effect size in depression.
        Eur Neuropsychopharmacol. 1994; 4: 283-284