Nicholas Christakis is an internist and social scientist who conducts research on social factors that affect health and health care. Dr. Christakis is professor of medical sociology in the department of health care policy at Harvard Medical School; he is professor of sociology in the department of sociology in the Harvard Faculty of Arts and Sciences; and he is an attending physician in the department of medicine at the Harvard-affiliated Mt. Auburn Hospital.

Dr. Christakis' past work has examined the accuracy and role of prognosis in medicine, ways of improving end-of-life care, and the determinants and outcomes of hospice use. His book on prognosis, Death Foretold: Prophecy and Prognosis in Medical Care, was published by the University of Chicago Press in 1999 and has been broadly reviewed and translated into Japanese (in 2006).

Currently, he is principally concerned with health and social networks, and specifically with how ill health, health behavior, health care, and death in one person can influence the same phenomena in others in a person's social network. Some current work is focused on the health benefits of marriage and on how ill health in one spouse can have cascading effects on the other spouse. It seems likely that improving the health of one partner in a marriage can have meaningful effects on the health of the other, and that both parties would value this - in a way that influences health policy. Other work examines a very large social network (of 12,000 people, including family, friends, and neighbors) followed for over 30 years to look broadly at the role of networks in health and health care.