Dr. Williams is Sol Katz Professor of General Internal Medicine and Professor of Health Care Management in the Wharton School. He was Chief of the Division of General Internal Medicine from 1992 to 2008, and directed Penn's Robert Wood Johnson Foundation Clinical Scholars Program from 1988 to 1996. He is a Deputy Editor of the Annals of Internal Medicine.
Dr. Williams has published more than 60 original articles that describe his work as a health services researcher, which has concentrated on physicians' decisions to use clinical resources, often regarding the use of diagnostic tests. His work also has focused on patient classification systems used by researchers to adjust outcomes for severity of illness.
Dr. Williams is a former President of the Society for Medical Decision Making, and he has given invited lectures to numerous professional and scientific audiences here and abroad. He was appointed Commissioner on the U.S. Congress's Prospective Payment Assessment Commission, which advised Congress about changes in Medicare payments to hospitals. He has had leadership roles in the Society of General Internal Medicine, including Editor of the Journal of General Internal Medicine (1995–1999), President of the Society (2000–2001), and recipient of the Society's 2008 Robert J. Glaser Award for exceptional contributions in education and research.