1 Cochrane Institute for Primary Care and Public Health, Cardiff University, Cardiff CF14 4YS, UK; Department of Family Practice, University of British Columbia, Vancouver, BC, Canada; Centre of Medical Informatics, University of Edinburgh, Edinburgh, UK. Electronic address: carson-stevensap@cardiff.ac.uk.
2 Cochrane Institute for Primary Care and Public Health, Cardiff University, Cardiff CF14 4YS, UK.
3 Centre of Medical Informatics, University of Edinburgh, Edinburgh, UK.
4 Institute for Healthcare Improvement, Cambridge, MA, USA; Harvard Medical School, Boston, MA, USA.
5 Centre of Medical Informatics, University of Edinburgh, Edinburgh, UK; Harvard Medical School, Boston, MA, USA; Brigham and Women's Hospital, Boston, MA, USA.
6 Department of Surgery and Cancer, Imperial College London, London, UK.