1. An anonymised manuscript

Review is double-blind, so this file must not identify you. Remove author names and affiliations, identifying acknowledgements, funding details that give you away, and any self-citation phrased as “as we showed in…”. The editorial office checks this before your paper goes to reviewers, and will return it to you if anything is left in.

2. A separate title page

Title, every author, their affiliations, and which one is the corresponding author. Reviewers never see this file.

3. An abstract and keywords

Between 50 and 250 words, and 3 to 6 keywords.

4. Declarations

That the work is original and not under review elsewhere, any competing interests, funding, and ethical approval where people took part in the research.

5. Supplementary material

Instruments, data or appendices, if you have any.