Is it possible to plagiarise oneself?
As suggested by an article entitled "Self-plagiarism: Oxymoron, fair use, or scientific misconduct?" by Broome (2004), the term 'self-plagiarism' may indeed sound like an oxymoron (a contradiction in terms). However, as Broome writes,
Unlike plagiarism, a practice in which one copies the work of another individual without acknowledgement of the original source, self-plagiarism refers to the not-so-uncommon practice of "reusing" some of one's own already-published writings in a subsequently published article. This is related to, but not the same thing as, duplicate publishing when an author submits (and has accepted and published) the same manuscript to 2 different journals with very little change in any of the text. (p. 273)
Re-publication of texts may, of course, be warranted, for instance when a text is translated, an out-of-print text is being republished, or when previously published facts are presented in a new way and with a new aim.
In some fields it is common for researchers to publish several articles on similar issues, and the borders between what is new material and what can be regarded as re-publication can be fuzzy. Writers therefore need to make sure that they follow the policies of journals and publishing houses, many of which have strict regulations concerning duplicate, or dual, publication. It is generally understood that texts should not be simultaneously submitted to more than one publisher and that writers should always state any correlation to their own previous publications on the topic.
Acknowledging related publications
Whenever a text or part of a text is re-published, reference to the original publication must be given.
Below are authentic examples of three common forms of scholarly re-publication that show different ways of phrasing such references to previous publications. Writers should always check with editors and journal guidelines for preferred style, since practices may vary between disciplines and between journals.
To avoid copyright violation, writers must also obtain permission for re-publication from the copyright holder of the original text (illustration, etc.).