Page "Scientific misconduct" Paragraph 18

* Conversely, research misconduct is not limited to NOT listing authorship, but also includes the conferring authorship on those that have not made substantial contributions to the research.

This is done by senior researchers who muscle their way onto the papers of inexperienced junior researchers as well as others that stack authorship in an effort to guarantee publication.

This is much harder to prove due to a lack of consistency in defining " authorship " or " substantial contribution ".