Interpretation of Changes in Health-related Quality of Life: The Remarkable Universality of Half a Standard Deviation

@article{Norman2003InterpretationOC,
  title={Interpretation of Changes in Health-related Quality of Life: The Remarkable Universality of Half a Standard Deviation},
  author={Geoffrey R Norman and Jeff Sloan and KathleenW. Wyrwich},
  journal={Medical Care},
  year={2003},
  volume={41},
  pages={582-592}
}
Background. A number of studies have computed the minimally important difference (MID) for health-related quality of life instruments. Objective. To determine whether there is consistency in the magnitude of MID estimates from different instruments. Methods. We conducted a systematic review of the literature to identify studies that computed an MID and contained sufficient information to compute an effect size (ES). Thirty-eight studies fulfilled the criteria, resulting in 62 ESs. Results. For… 
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Interpreting Health-Related Quality of Life Scores
  • Medicine, Psychology
  • 2003
TLDR
The article by Norman et al. addresses the interpretation of health-related quality of life scores and concludes that the threshold of discrimination for change is approximately 0.5 SD.
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