Evidence Ratings

Evidence of Effectiveness Strength Rating

For each review, studies that meet the established inclusion criteria are summarized in a standardized format to generate a body of evidence. This body of evidence is rated using one of four categories for an overall evidence of effectiveness strength rating based on the combination of an effect size rating and study quality rating.

**Evidence of effectiveness strength rating**
Strength Ratings	Combined Evidence Minimum Criteria
	#Studies*	Effect Size Rating	Quality Rating
High	≥ 3	Substantial	Good
Moderate	≥ 2 ≥ 3	Substantial Moderate	Good Good
Suggestive (Low)	≥ 1 ≥ 2 ≥ 3	Substantial Moderate Moderate	Good Good Good
Insufficient (Very Low)		All Others

Categories of Best Practices Recommendations

The following categories are used by an independent LMBP Workgroup to elaborate on LMBP systematic review findings.

**Categories of Best Practices Recommendations**
Recommendation Categories*	Recommendation Categories*
Recommend	Consistent and high or moderate overall evidence of effectiveness strength rating of desirable effects
No recommendation for or against	Insufficient evidence to determine effectiveness
Recommend against	Consistent evidence of adverse effects

* CDC does not make the recommendations, but aims to be a guarantor of the process by which the independent Workgroup makes its conclusions and recommendations.

Page last reviewed: November 28, 2018

Content source: Division of Laboratory Systems (DLS)