The guideline underwent extensive review. But reviewing guidelines is different from reviewing other original research reports. It is very difficult, if not impossible, for any peer reviewer or professional society to review the evidence in the same way that a guideline committee aggregated, analyzed, and synthesized the data. A committee, comprising methodologists, statisticians, and content experts, is required to write a high-quality guideline, so expecting a single individual or a professional society to repeat that process is not practical. So how are guidelines reviewed? In this case, as detailed in the report,2 the guideline underwent rigorous initial review by numerous experts and relevant organizations, and based on those reviews, was revised prior to being submitted to JAMA. At JAMA there was broad unanimity among the external peer reviewers and internal editorial reviewers that the guideline was comprehensive, concise, and clear and that it appropriately acknowledged the areas of controversy. The evidence tables and supplemental material were also reviewed and were thought to be comprehensive. In addition, the reviewers were impressed with the diligence with which the committee adhered to the recommendations of the Institute of Medicine for how guidelines should be developed. Following this review, suggestions to improve the guideline were incorporated and inconsistencies were eliminated; the revised guideline is published along with the supporting evidence. In addition, the authors have indicated that they will make the extensive comments from the presubmission guideline review process available to readers on request.