Gregory Stevens, Ph.D, M.H.S., is an Associate Professor of Family Medicine and Preventive Medicine at the Keck School of Medicine of the University of Southern California. He is a health policy researcher, writer, teacher and advocate. He holds an M.H.S. and Ph.D. from the Johns Hopkins University Bloomberg School of Public Health, with a focus on health care policy. He is an author of the book Vulnerable Populations in the United States and serves as a co-Editor of a health care policy blog at the journal Medical Care.