6. Recommendations
The strength of a recommendation reflects the extent to which a guideline panel is confident that desirable effects of an intervention outweigh undesirable effects, or vice versa, across the range of patients for whom the recommendation is intended. GRADE specifies only two categories of the strength of a recommendation. While GRADE suggests using the terms strong and weak recommendations, those making recommendations may choose different wording to characterize the two categories of strength.
For a guideline panel or others making recommendations to offer a strong recommendation, they have to be certain about the various factors that influence the strength of a recommendation. The panel also should have the relevant information at hand that supports a clear balance towards either the desirable effects of an intervention (to recommend an action) or undesirable effects (to recommend against an action). A strong recommendation is one for which the guideline panel is confident that the desirable effects of an intervention outweigh its undesirable effects (strong recommendation for an intervention) or that the undesirable effects of an intervention outweigh its desirable effects (strong recommendation against an intervention). A strong recommendation implies, that most or all individuals will be best served by the recommended course of action.
When a guideline panel is uncertain whether the balance is clear or when the relevant information about the various factors that influence the strength of a recommendation is not available, a guideline panel should be more cautious and in most instances it would opt to make a weak recommendation. A weak recommendation is one for which the desirable effects probably outweigh the undesirable effects (weak recommendation for an intervention) or undesirable effects probably outweigh the desirable effects (weak recommendation against an intervention) but appreciable uncertainty exists. A weak recommendation implies, that not all individuals will be best served by the recommended course of action. There is a need to consider more carefully than usual individual patient’s circumstances, preferences, and values.
6.1. Four key factors influence the strength of a recommendation
- Balance between desirable and undesirable effects (not considering costs)
The larger the difference between the desirable and undesirable consequences, the more likely a strong recommendation is warranted. The smaller the net benefit and the lower the certainty for that benefit, the more likely a weak recommendation is warranted.
- Quality of the evidence
The higher the quality of evidence, the more likely is a strong recommendation.
- Values and preferences
The greater the variability in values and preferences, or uncertainty in values and preferences, the more likely a weak recommendation is warranted.
- Costs (resource utilization)
The higher the costs of an intervention – that is, the more resources are consumed – the less likely a strong recommendation is warranted.
6.2. Wording of a recommendation
Wording of a recommendation should offer clinicians as many indicators as possible for understanding and interpreting the strength of recommendations:
- For strong recommendations, the GRADE working group has suggested adopting terminology, such as "we recommend..." or "clinicians should...".
- For weak recommendations, the GRADE working group has suggested less definitive wording, such as "we suggest..." or "clinicians might...".
Whatever terminology guideline panels use to communicate the dichotomous nature of a recommendation, it is essential that they inform their users what the terms imply. Guideline panels should describe patients or populations (characterized by the disease and other identifying factors) for whom the recommendation is intended and a recommended intervention as specifically and detailed as possible.
Wording strong and weak recommendations is particularly important when guidelines are developed by international organizations and/or are intended for patients and clinicians in different regions, cultures, traditions, and usage of language. It is also crucial to explicitly and precisely consider wording when translating recommendations into different languages.
It is important to adapt the wording of the recommendation to the available evidence. Absence of a statistically significant effect is no proof that an intervention does not work. It is only proven that an intervention doesn’t work if the confidence interval around the effect estimation excludes a minimally important difference or decision threshold.