Elwood is often referred to as the "father of the health maintenance organization. He not only coined the term, he also played a role in bringing about structural changes to the American health care system to simultaneously control cost and promote health by replacing fee-for-service with prepaid, comprehensive care. With N. N. Anderson, J.E. Billings, R.J. Carlson, E.J. Hoagberg, and W. McClure.