Duplicate publication

Duplicate publication, multiple publication, or redundant publication refers to publishing the same intellectual material more than once, by the author or publisher. It does not refer to the unauthorized republication by someone else, which constitutes plagiarism, copyright violation, or both.

Multiple submission is not plagiarism, but it is today often viewed as academic misbehavior because it can skew meta-analyses and review articles and can distort citation indexes and citation impact by gaming the system to a degree. It was not always looked upon as harshly, as it began centuries ago and, besides the negative motive of vanity which has always been possible, it also had a legitimate motive in reaching readerships of various journals and books that were at real risk of not otherwise overlapping. This was a print-only era before modern discoverability via the internet and digital search and before systematic reviews, meta-analyses, and citation indexes existed, and despite a few rudimentary journal clubs, it was likely for readers who subscribed to journals in one city, region, or specialty to have only sporadic contact with journals from other places or specialties. Thus redundant publication could serve a valid purpose analogous to the way that various newspapers in different cities and countries often report news items from elsewhere, ensuring that people in many places receive them despite that they do not read multiple periodicals from many other places. However, as discoverability increased in the 20th century and the aforementioned concerns arose, critical views of redundant publication, beyond merely reproaching vanity, took shape. A formalization of the policy of disallowing duplicate publications was given by Franz J. Ingelfinger, the editor of The New England Journal of Medicine, in 1969. He coined the Ingelfinger rule term banning republications in the journal. Most journals follow this policy today. The BMJ, for example, requires copies of any previous work with more than 10% overlap of a submission to be submitted before approving a work for publication.

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