1. Department of Health, Welfare and Organisation, Østfold University College, Halden, Norway
2. Department of Health Management and Health Economics, Norway, University of Oslo, Oslo, Norway
3. Health Services Research Unit, Akershus University Hospital, Lørenskog, Norway
4. Institute of Clinical Medicine, University of Oslo, Lørenskog, Norway
5. Department of Anesthesia, Østfold Hospital Trust, Grålum, Norway