Mark Pauly is the Bendheim Professor of health care management at the Wharton School at the University of Pennsylvania in Philadelphia. He is an expert on medical economics, health policy and health insurance.

Abigail Rian Evans is an adjunct professor of family medicine at the Georgetown University Medical Center in Washington, D.C. She wrote Redeeming Marketplace Medicine: A Theology of Health Care.

Jacob S. Hacker is the Stanley B. Resor Professor of Political Science at Yale University and a Resident Fellow at the Institution for Social and Policy Studies. He edited Health at Risk: America’s Ailing Health System – and How to Heal It.

Jonathan Gruber is an economics professor at Massachusetts Institute of Technology in Boston. He advised the Obama campaign in 2008 about health care, and The Washington Post has called him the Democratic Party’s most influential health care expert. He has testified before the Senate Finance Committee about financing health care reform.

David Cutler is an economics professor at Harvard University. He wrote the book Your Money or Your Life: Strong Medicine for America’s Healthcare System, which looks at issues involving access to health care.

Stuart Altman is the Sol C. Chaikin Professor of National Health Policy at the Heller School for Social Policy and Management at Brandeis University in Waltham, Mass. He is an economist whose research interests are primarily in federal and state health policy.

The U.S. Census Bureau provides data on the uninsured, including breakdowns by age, race, sex and state.

The State Health Access Data Assistance Center at the University of Minnesota provides information and analysis about health insurance coverage with state-by-state profiles.

Read an analysis by Drew Altman, president and CEO of the Henry J. Kaiser Family Foundation, about differences in public and expert perceptions of the current American health care system.