From evidence to action

Figures & data

Table 1. Evidence-based criteria to grade the quality of evidence (Schunemann et al. 2006b)

Quality of evidence	Study design	Lower if ^a	Higher if ^a
High (4)	Randomized trial	Study limitations	Large effect
		– 1 serious	+ 1 large
		– 2 very serious	+ 2 very large
Moderate (3)		Inconsistency	Dose response
		– 1 serious	+ 1 evidence of a gradient
		– 2 very serious
Low (2)	Observational study	Indirectness	All plausible confounding
		– 1 serious
		– 2 very serious	+ 1 would reduce a demonstrated effect, or
Very low (1)		Imprecision
		– 1 serious	+ 2 would suggest a spurious effect when results
		– 2 very serious
		Publication bias	show no effect
		– 1 likely
		– 2 very likely

^a 1 = move up or down one grade (for example from high to intermediate) 2 = move up or down two grades (for example from high to low)

Table 2. Determinants of strength of recommendation (Schunemann et al. 2006b)

Factors that can strengthen the strength of a recommendation	Comment
Balance between desirable and undesirable effects	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 weak recommendations are warranted.
Quality of the evidence	The higher the quality of evidence, the more likely 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 allocation)	The higher the costs of an intervention—that is, the more resources consumed— the less likely a strong recommendation is warranted.

Table 3. The COGS checklist for reporting clinical practice guidelines (Shiffman et al. 2003) ^a

Topic	Description
1. Overview material	Provide a structured abstract that includes the guideline’s release date, status (original, revised, updated), and print and electronic sources.
2. Focus	Describe the primary disease/condition and intervention/service/technology that the guideline addresses. Indicate any alternative preventive, diagnostic, or therapeutic interventions that were considered during development.
3. Goal	Describe the goal that following the guideline is expected to achieve, including the rationale for development of a guideline on this topic.
4. Users/setting	Describe the intended users of the guideline (e.g., provider types, patients) and the settings in which the guideline is intended to be used.
5. Target population	Describe the patient population eligible for guideline recommendations and list any exclusion criteria.
6. Developer	Identify the organization(s) responsible for development of the guideline and the names/credentials/potential conflicts of interest of individuals involved in the development.
7. Funding sources/sponsor	Identify the funding source/sponsor and describe its role in developing and/or reporting the guideline. Disclose potential conflicts of interests.
8. Evidence collection	Describe the methods used to search the scientific literature, including the range of dates and databases searched, and criteria applied to filter the evidence retrieved.
9. Recommendation grading criteria	Describe the criteria used to rate the quality of evidence that supports the recommendations, and the system for describing the strength of the recommendations. Recommendation strength communicates the importance of adherence to a recommendation and is based on both the quality of the evidence and the magnitude of anticipated benefits or harm.
10. Method for synthesizing evidence	Describe how evidence was used to create recommendations, e.g., evidence tables, meta-analysis, decision analysis.
11. Prerelease review	Describe how the guideline developer reviewed and/or tested the guidelines prior to release.
12. Update plan	State whether or not there is a plan to update the guideline and, if applicable, an expiration date for this version of the guideline.
13. Definitions	Define unfamiliar terms, and those that are critical to correct application of the guideline and that might be subject to misinterpretation.
14. Recommendations and rationale	State the recommended action precisely and the specific circumstances under which to perform it. Justify each recommendation by describing the linkage between the recommendation and its supporting evidence. Indicate the quality of evidence and the strength of recommendation, based on the criteria described in 9.
15. Potential benefits and harm	Describe anticipated benefits and potential risks associated with implementation of guideline recommendations.
16. Patient preferences	Describe the role of patient preferences when a recommendation involves a substantial element of personal choice or values.
17. Algorithm	Provide (where appropriate) a graphical description of the stages and decisions in clinical care described by the guide line.
18. Implementation considerations	Describe anticipated barriers to application of the recommendations. Provide references to any auxiliary documents for providers or patients that are intended to facilitate implementation. Suggest review criteria for measuring changes in care when the guideline is implemented.

^a COGS: Conference on Guideline Standardization.

Evidence-based guideline development.

Schunemann HJ, Fretheim A, Oxman AD. Improving the use of research evidence in guideline development: 9. Grading evidence and recommendations. Health Res Policy Syst 2006b; 4: 21

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Shiffman RN, Shekelle P, Overhage JM, Slutsky J, Grimshaw J, Deshpande AM. Standardized reporting of clinical practice guidelines: a proposal from the Conference on Guideline Standardization. Ann Intern Med 2003; 39: 493–8

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