Author contribution statements are now mandatory and author responsibilities have been clarified.
Nature Cell Biology has encouraged author declarations for a decade and now almost 90% of papers carry them. The declaration is important as it adds transparency and accountability, as well as assigning credit. In an effort to standardize the information, we have now made it mandatory. While authors can structure them as they see fit, we require that every author is listed.
Although the corresponding author(s) of a paper is implicitly responsible for the accuracy and integrity of the data presented, we have refined our guidelines on author responsibility: in a collaboration, a senior researcher must take responsibility for the contribution of each group. This includes verifying that the data and conclusions accurately reflect the source data, that data analysis and image manipulations have been made in accordance with our guidelines (http://www.nature.com/ncb/authors/index.html), that the original data have been archived and that materials, data and algorithms have been deposited in the appropriate databases and will be distributed to interested parties. Corresponding authors are responsible for ensuring that all co-authors agree with the content and author list of a manuscript and for informing them of issues that arise before and after publication; they must certify that their manuscript fulfils the policies outlined at http://www.nature.com/authors/editorial_policies/authorship.html as part of the online submission process.