Any change in authors and/or contributors after initial submission must be approved by all authors. This applies to additions, deletions, change of order to the authors, or contributions being attributed differently. Any alterations must be explained to the editor. The editor may contact any of the authors and/or contributors to ascertain whether they have agreed to any alteration.
If there is a very large number of authors, we may ask for confirmation that everyone listed met the ICMJE criteria for authorship. If they did, we may then require that the authors form a group whose name will appear in the article byline.
We appreciate that authors may be concerned that their work will not be properly recognized if they form a group, but this is unfounded.