André Hajek is Professor for Interdisciplinary Health Care Epidemiology, Department of Health Economics and Health Services Research at the University Medical Center Hamburg-Eppendorf, Germany. Steffi G. Riedel-Heller is Professor of Social Medicine and Public Health, and Director of the Institute of Social Medicine, Occupational Health and Public Health (ISAP), University of Leipzig, Germany. Hans-Helmut König is Professor of Health Services Research and Health Economics, and Director of the Department of Health Economics and Health Services Research at the University Medical Center Hamburg-Eppendorf, Germany.