PIER and Medical Evidence PIER is designed to be comprehensive, synoptic, and timely. Unlike most guidelines, PIER includes recommendations based on all levels of medical evidence including RCTs, cohort and observational studies, case reports, and expert opinion. Recommendations in PIER include strength-of-recommendation ratings based on the quality of underlying evidence, and each cited reference is graded according to level of evidence. All PIER content is rigorously peer reviewed. All PIER modules are updated continually by editorial consultants with the support of periodic searches of the medical literature performed by experts in evidence-based medicine. Next Contents The information in PIER should never be used as a substitute for clinical judgment and does not represent an official position of ACP. PIER is copyrighted (c) 2009 by the American College of Physicians, 190 N. Independence Mall West, Philadelphia, PA 19106-1572, USA.