Davis returned to academia in 1981 as a professor of economics and chairman of the Department of Health Policy and Management at the Johns Hopkins School of Public Health. She continued to research effective strategies for healthcare cost containment, and through teaching, she says, tried to convince more students to go into the field of health policy and economics.
With a background in economics, Davis absolutely believes in the power of comparative data to change minds and inform policy. In 1992, Davis began to work for the Commonwealth Fund, the private foundation established in 1918 with the mission to "promote a high-performing healthcare system that achieves better access, improved quality, and greater efficiency, particularly for society's most vulnerable, including low-income people, the uninsured, minority Americans, young children, and elderly adults."
From 1995 to 2012, while Davis served as the president of The Commonwealth Fund, she was frustrated with how the U.S. healthcare system compared internationally with systems that not only provided higher rates of healthcare coverage for their citizens, but managed to afford it.
In 2005 she established the Commonwealth Fund Commission on a High Performance Health System. The comparative outcomes and quality of care data the Commonwealth Fund put forth demonstrated that the United States clearly did not have the best health system in the world. Davis says this comparative research on international systems helped to "motivate and create the will for change" in Congress.