lieve serves the needs of their specialty. Under that system, evidence from individual studies is rated as Level 1, 2, or 3; bodies of evidence are referred to as consistent or inconsistent; and the strength of recommendations are indicated by the letter A, B, or C (Ebell et al., 2004).

In addition to making efforts to reach agreement on grading scales, several groups have sought to standardize guideline development methodologies. Although there is still no internationally accepted standard for guideline development, there have been repeated calls for a “guideline for guidelines” (Guyatt et al., 2006b; Jackson and Feder, 1998; Schünemann et al., 2006; Shaneyfelt et al., 1999; Shekelle et al., 1999; Shiffman et al., 2003).

Among the more prominent efforts to standardize and raise the quality of clinical practice guidelines are the Appraisal of Guidelines Research and Evaluation (AGREE) collaboration and the Conference on Guideline Standardization (COGS). The AGREE collaboration defines the quality of guidelines as “the confidence that the potential biases inherent of guideline development have been addressed adequately and that the recommendations are both internally and externally valid, and are feasible for practice”