The American College of Physicians (ACP) established its evidence-based clinical practice guidelines program in 1981. The ACP's Guidelines Committee and the staff of the Clinical Programs and Quality of Care Department develop the clinical recommendations. The ACP develops 2 different types of clinical recommendations: clinical practice guidelines and clinical guidance statements. The ACP clinical practice guidelines and guidance statements follow a multistep development process that includes a systematic review of the evidence, deliberation of the evidence by the committee, summary recommendations, and evidence and recommendation grading. All ACP clinical practice guidelines and clinical guidance statements, if not updated, are considered automatically withdrawn or invalid 5 years after publication or once an update has been issued.