Episode 7 of CRAMSURG - Clinical Reasearch Appraisal and Methodology for Surgical Trainees. The paper for discussion is Classifying Preoperative Opioid Use for Surgical Care, Ann Surg Jun 2020. The teaching topic is Measures of Risk - part 2 (ARR, RRR, NNT). Brought to you by CRAMSURG www.cramsurg.org.