Table 3.

Criteria for rating the quality of the body of evidence^* by outcome of interest

Rating	Description
1= GOOD	Evidence includes consistent results from well-designed, well-conducted studies in representative populations that directly assess effects on health outcomes
2= FAIR:	Evidence is sufficient to determine effects on health outcomes, but the strength of the evidence is limited by the number, quality, or consistency of the individual studies, generalizability to routine practice, or indirect nature of the evidence on health outcomes.
3= POOR	Evidence is based on consensus, usual practice, opinion, or case series. Additionally evidence is insufficient to fully assess the effects on health outcomes because of limited number, or power of studies, important flaws in design or conduct, gaps in the chain of evidence, or lack of information on importance on the key health outcomes

^*Adapted from the US Preventive Services Task Force Procedure Manual⁷.