Don't middle your MIDs: Regression to the mean shrinks estimates of minimally important differences

Peter M. Fayers* (Corresponding Author), Ron D. Hays

*Corresponding author for this work

Research output: Contribution to journalArticle

41 Citations (Scopus)


Minimal important differences (MIDs) for patient-reported outcomes (PROs) are often estimated by selecting a clinical variable to serve as an anchor. Then, differences in the clinical anchor regarded as clinically meaningful or important can be used to estimate the corresponding value of the PRO. Although these MID values are sometimes estimated by regression techniques, we show that this is a biased procedure and should not be used; alternative methods are proposed.

Original languageEnglish
Pages (from-to)1-4
Number of pages4
JournalQuality of Life Research
Issue number1
Early online date31 May 2013
Publication statusPublished - Feb 2014



  • Clinical significance
  • Minimally important difference
  • Patient-reported outcomes
  • Quality of life
  • Regression to the mean

ASJC Scopus subject areas

  • Public Health, Environmental and Occupational Health

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