1. Norwegian Knowledge Centre for the Health Services; Global Health Unit; PO Box 7004, St. Olavs Plass Oslo Norway N-0130
2. Norwegian Knowledge Centre for the Health Services; Prevention, Health Promotion and Organisation Unit; PO Box 7004 St Olavs Plass Oslo Norway 0130
3. Carl von Ossietzky University of Oldenburg; Department of Health Services Research; Oldenburg Germany
4. University of Basel Hospital; asim, Swiss Academy of Insurance Medicine; University of Basel Petersgraben 4 Basel Switzerland 4031
5. American University of Beirut; Department of Internal Medicine; Riad El Solh St Beirut Lebanon
6. McMaster University; Departments of Clinical Epidemiology and Biostatistics and of Medicine; 1280 Main Street West Hamilton ON Canada L8N 4K1
7. University Hospital Basel (USB); Basel Institute for Clinical Epidemiology and Biostatistics; Basel Switzerland
8. University Hospital Basel; Institute for Clinical Epidemiology and Biostatistics; Hebelstrasse 10 Basel Switzerland 4031
9. University of Modena and Reggio Emilia; Cattedra di Statistica Medica; Via del Pozzo 71 41100 Modena Italy