Intended for healthcare professionals

Analysis Rating quality of evidence and strength of recommendations

Going from evidence to recommendations

BMJ 2008; 336 doi: (Published 08 May 2008) Cite this as: BMJ 2008;336:1049

This article has a correction. Please see:

  1. Gordon H Guyatt, professor1,
  2. Andrew D Oxman, researcher2,
  3. Regina Kunz, associate professor3,
  4. Yngve Falck-Ytter, assistant professor4,
  5. Gunn E Vist, researcher2,
  6. Alessandro Liberati, associate professor5,
  7. Holger J Schünemann, associate professor6
  8. for the GRADE Working Group
  1. 1CLARITY Research Group, Department of Clinical Epidemiology and Biostatistics, McMaster University, Hamilton, ON, Canada L8N 3Z5
  2. 2Norwegian Knowledge Centre for the Health Services, Oslo, Norway
  3. 3Basel Institute of Clinical Epidemiology, University Hospital Basel, Basel, Switzerland
  4. 4Division of Gastroenterology, Case Medical Center, Case Western Reserve University, Cleveland, OH 44106, USA
  5. 5University of Modena and Reggio Emilia and Agenzia Sanitaria Regionale, Bologna, Italy
  6. 6Department of Epidemiology, CLARITY Research Group, Italian National Cancer Institute Regina Elena, Rome, Italy
  1. Correspondence to: G H Guyatt guyatt{at}

The GRADE system classifies recommendations made in guidelines as either strong or weak. This article explores the meaning of these descriptions and their implications for patients, clinicians, and policy makers

Summary points

  • The strength of a recommendation reflects the extent to which we can be confident that desirable effects of an intervention outweigh undesirable effects

  • GRADE classifies recommendations as strong or weak

  • Strong recommendations mean that most informed patients would choose the recommended management and that clinicians can structure their interactions with patients accordingly

  • Weak recommendations mean that patients’ choices will vary according to their values and preferences, and clinicians must ensure that patients’ care is in keeping with their values and preferences

  • Strength of recommendation is determined by the balance between desirable and undesirable consequences of alternative management strategies, quality of evidence, variability in values and preferences, and resource use

This is the third of a series of five articles describing the GRADE approach to developing and presenting recommendations for management of patients. In it, we deal with how GRADE suggests clinicians should interpret the strength of a recommendation.

What do we mean by strength of recommendation?

The strength of a recommendation reflects the extent to which we can, across the range of patients for whom the recommendations are intended, be confident that the desirable effects of an intervention outweigh the undesirable effects. Alternatively, in considering two or more possible management strategies, a recommendation’s strength represents our confidence that the net benefit clearly favours one alternative or another.

Desirable effects of an intervention include reduction in morbidity and mortality, improvement in quality of life, reduction in the burden of treatment (such as having to take drugs or the inconvenience of having blood tests or going to the doctor’s office for monitoring), and reduced resource expenditures. Undesirable consequences include adverse effects that may have a deleterious impact on morbidity, mortality, …

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