From the aDepartment of Health Management and Health Economics, University of Oslo, Oslo, Norway; bDepartment of Transplantation Medicine and KG Jebsen Center for Colorectal Cancer Research, Oslo University Hospital, Oslo, Norway; and cDepartment of Epidemiology, Harvard School of Public Health, Boston, MA.
This paper is dedicated to our friend and mentor Marvin Zelen (1927–2014).
The authors report no conflicts of interest.
Correspondence: Michael Bretthauer, Department of Health Management and Health Economics, University of Oslo, Oslo, Norway. E-mail: email@example.com.