1 Professor, Clinical Effectiveness Research Group, University of Oslo; Oslo University Hospital, Oslo, Norway.
2 Researcher, Clinical Effectiveness Research Group, University of Oslo; Oslo University Hospital, Oslo, Norway.
3 Professor, Institute of Health and Society, Faculty of Medicine, University of Oslo, Oslo, Norway; Department of Medicine, Lovisenberg Diaconal Hospital, Oslo, Norway.
4 Assistant professor, Division of General Internal Medicine, University Hospitals of Geneva, Geneva, Switzerland.
5 Professor, Department of Health Research Methods, Evidence and Impact, McMaster University, Hamilton, Ont.