Who should be an author?

Over recent months I have been approached by authors of accepted or already published papers with requests to remove an author or to add an author. Typically, they think that this is a trivial request that can be easily accommodated with little explanation other than ‘after the manuscript was accepted we remembered that author X was actually away at the time we did the experiments and wrote them up’ or ‘after the paper appeared on-line (or in the journal) X reminded us that he actually performed some of the work or had valuable input into the interpretation of the results’. In fact, modifying authorship of a paper at any stage is not trivial, although it may be legitimate. For example, when a manuscript is being revised following receipt of reviewers’ comments some experiments and/or interpretations may be removed, meaning that an author who was involved only in those parts of the manuscript should be removed. Likewise, new data may be added, new experiments performed, or new interpretations included, and these may require the addition of one or more authors. These changes are easily accommodated by mentioning and explaining them in the response to reviewers’ comments and they do not present any difficulty. However, changing authorship once a manuscript has been accepted for publication is more difficult. It could be done with no ‘outside’ knowledge at the correction of proofs stage, but will require publication of a correction if done once a paper is published, even if this is on-line. If an author is to be removed or added at the proofs stage or once a paper is published, then there is a formal procedure to be entered into to achieve this. This is outlined by the Committee on Publication Ethics and essentially requires (a) a valid reason for making the change and (b) a signed letter from all authors including those to be removed or added indicating agreement to the removal or addition. Note that if an author is removed or added after publication of the paper on-line then that version of the paper cannot be modified and will remain in its original form; the modification is made in a separate correction. The forgoing discussion prompts me to remind readers of the rules governing authorship and contributorship, as specified by the International Committee of Medical Journal Editors. An ‘author’ is generally considered to be someone who has made substantive intellectual contributions to a published study. In the past, readers were rarely provided with information about contributions to studies from those persons listed as authors. However, the British Journal of Nutrition now requires that contributions of all authors be listed at the end of the text. But what are the quantity and quality of contribution that qualify for authorship? The International Committee of Medical Journal Editors has recommended that authorship should be based on: