American College Of Surgeons - Inspiring Quality: Highest Standards, Better Outcomes

ACS Clinical Scholar in Residence Mentors

Clifford Ko, MD, MS, MSHA, FACS

Clifford Ko, MD, MS, MSHS, FACS

Director, Division of Research and Optimal Patient Care, American College of Surgeons (ACS), Chicago, IL

Dr. Ko is the Director of the Division of Research and Optimal Patient Care at the American College of Surgeons (ACS) where he oversees all the quality improvement and accreditation/verification programs and activities of the division, including those related to bariatric, cancer, pediatric, and trauma surgeries. He also oversees the Surgeon Specific Registry (SSR), the Coalition for Quality in Geriatric Surgery (CQGS), and the Improving Surgical Care and Recovery (ISCR) project informed for enhanced recovery protocols. Dr. Ko also serves as the Director of the ACS National Surgical Quality Improvement Program (ACS NSQIP), and professor of surgery at the University of California, Los Angeles. He is a double board-certified surgeon, specializing in general and colorectal surgery, and a formally trained health services researcher. Prior to working at the ACS, he served as a research scientist at the RAND Corporation. Dr. Ko has published nearly 400 peer-reviewed articles, written more than 20 book chapters, and received peer-reviewed funding from several sources including the National Institutes of Health and the Agency for Healthcare Research and Quality. He has extensive experience in guiding residents and fellows conducting research on health outcomes.


Karl BilimoriaKarl Bilimoria, MD, MS

Northwestern University, Chicago, IL

Dr. Bilimoria is a surgical oncologist focusing on melanoma and sarcoma, and a health services and quality improvement researcher at Northwestern University. Dr. Bilimoria is the director of the Surgical Outcomes and Quality Improvement Center of Northwestern University (SOQIC) and the vice chair for quality. He also leads the Northwestern Institute for Comparative Effectiveness Research in Oncology (NICER-Onc). Dr. Bilimoria’s research agenda focuses on improving health care quality measurement and delivery. He has a particular interest in large, pragmatic cluster-randomized trials examining hospital quality initiatives and health care policies.

He is the director of the Illinois Surgical Quality Improvement Collaborative (ISQIC) and the principal investigator of the FIRST Trial, He is a Faculty Scholar at the American College of Surgeons (ACS). He has published more than 250 scientific articles with multiple recent studies in JAMA and NEJM, and his research is funded by the NIH, AHRQ, ACS, NCCN, ACS, ABS, ACGME, and HCSC. He currently serves on the SSO Executive Committee. He was recently listed as one of Becker’s “50 Experts Leading the Field of Patient Safety.”


Mark E. Cohen, PhDMark E. Cohen, PhD

Statistical Manager, Continuous Quality Improvement, Division of Research and Optimal Patient Care, American College of Surgeons, Chicago, IL

Dr. Cohen received a PhD in psychology from the University of Illinois, Chicago, and also completed graduate-level coursework in applied statistics at DePaul University, Chicago. Dr. Cohen was a National Institutes of Health postdoctoral fellow at the University of Wisconsin, Madison, and taught at Lake Forest College, Lake Forest, IL. Before coming to the College in 2008, he worked at a U.S. Navy Medical Research Laboratory for 28 years as a statistician and as technical (research) director. Dr. Cohen has authored 165 peer-reviewed articles. He manages the CQI statistics team which is responsible for profiling analytics for the ACS National Surgical Quality Improvement Program (ACS NSQIP), Pediatric NSQIP, and the Metabolic and Bariatric Surgery Accreditation and Quality Improvement Program (MBSAQIP), as well as other quantitative efforts involving ACS staff, consultants, and clinical scholars.


Bruce L. Hall, MD, PhD, MBA, FACSBruce L. Hall, MD, PhD, MBA, FACS

Dr. Hall received his MD and PhD from the NIH Medical Scientist Training Program at Duke University, Durham, NC, and later obtained an MBA from Harvard Business School, Boston, MA. Dr. Hall holds dual appointments as associate professor in the department of surgery at Washington University/Barnes-Jewish Hospital and the Olin Business School, St. Louis, MO. His clinical expertise includes thyroid and parathyroid surgery, surgical oncology, and trauma care. He joined the John Cochran Saint Louis VA Medical Center Surgical Service as the associate chief of surgery in 2007. He is also a senior fellow of the Center for Health Policy at Washington University.

Dr. Hall has focused his research on the evaluation of quality in surgery. He has particular interest in the theory of risk adjustment and advanced statistical techniques. He has directed the ACS NSQIP at his hospital since 2001. Nationally, Dr. Hall co-chairs the Measurement and Evaluation Committee for the ACS NSQIP, serves on the ACS NSQIP Policy Advisory Committee and the ACS Patient Safety and Quality Committee, represents the ACS to the National Quality Forum, and is a member of the physician engagement group for The Joint Commission. Dr. Hall has mentored a large number of students and residents conducting health outcomes research.


Ryan Merkow, MDRyan P. Merkow, MD, MS

Dr. Merkow is a board-certified surgical oncologist focusing on upper gastrointestinal malignancies, and is a health services researcher at Northwestern University. He received his formal training in health services research at the American College of Surgeons as a Clinical Scholar in Residence and completed a Master’s in Health Services and Outcomes Research in the Center for Healthcare Studies at Northwestern University. He is currently on faculty in the Surgical Outcomes and Quality Improvement Center (SOQIC) at Northwestern University and a Faculty Scholar at the American College of Surgeons. Dr. Merkow’s research focus includes perioperative surgical quality, cancer care quality measure development, and patient-reported outcomes. Dr. Merkow has published more than 65 scientific articles in journals such as JAMAJNCI, and Annals of Surgery. He has extensive experience mentoring students and residents in the field of health services research.