Great controversy exists regarding the safety of surgery when the attending surgeon allows someone else to perform parts of the operation. These practices are necessary components of surgical training, but how safe this is for patients remains unknown. In this podcast we discuss the risks and benefits associated with overlapping and concurrent surgery with a recognized expert in this topic, Michelle M. Mello, JD, PhD, a professor of law at Stanford University and the Department of Health Research and Policy, Stanford University School of Medicine, California.