1. Institute for Evidence in Medicine, Medical Center, University of Freiburg, Faculty of Medicine University of Freiburg Freiburg Germany
2. Faculty of Medicine and Medical Centre, Institute of Medical Biometry and Statistics University of Freiburg Freiburg Germany
3. School of Medical and Health Sciences Bangor University Bangor UK
4. School of Health and Related Research (ScHARR) University of Sheffield Sheffield UK
5. Norwegian Institute of Public Health, Oslo, Norway and Health Systems Research Unit South African Medical Research Council Cape Town South Africa
6. Cochrane Germany, Cochrane Germany Foundation Freiburg Germany