Footnotes

• Competing interests Sally Hopewell is Senior Research Fellow and a member of the CONSORT Group and is supported by the CONSORT grant funding provided by the UK Medical Research Council. Iveta Simera is Head of Programme Development of the EQUATOR Network and is supported by the EQUATOR programme funding provided by the UK NHS National Institute for Health Research, UK Medical Research Council, Scottish Chief Scientist Office, Pan American Health Organisation, and Canadian Institutes of Health Research. None of the above funders influenced in any way the content of this article.

• Provenance and peer review Commissioned; internally peer reviewed.