Duplicate publication is a form of redundant publication where the same article is published more than once, without acknowledging the first publication.
Secondary publication is an acceptable duplicate publication – the publication of the same article for different audiences – for example, in a different journal or in a different language.
Duplicate publications are redundant because they present the same data. As readers are not made aware of this fact, they could consider the two (or more) publications to be separate studies. This may be harmful when such studies are included in evidence synthesis, such as systematic reviews and meta-analyses about health interventions, because they may skew the evidence (1). This can lead to erroneous recommendations for health practice, which may result in increased risk for patients.
Journal publishers, Journal editors
This is the definition of duplicate publication by the Committee on Publication Ethics (COPE):
“When a published work (or substantial sections from a published work) is/are published more than once (in the same or another language) without adequate acknowledgment of the source/cross-referencing/justification”(2).
The International Committee of Medical Journal Editors (ICMJE) differentiates between duplicate submission – when authors submit the same work (possibly in different languages) to two or more journals at the same time; and duplicate publication – when the same work is already published more than once.
Duplicate publications must be retracted, and duplicate submissions, if discovered by journal editors, are usually rejected. COPE provides guidance on how to handle duplicate publications. Some indexing databases, such as PubMed, automatically tag duplicate publications when they identify them during indexation (3).
Acceptable secondary publication is publication of the same work but with clear reference to its first publication and approval for such publication. This means that authors must have approval from the journal that first published the article, that the secondary publication is a faithful reflection of the original publication and that is clearly indicates the primary publication – as a note in the article and in the title of the secondary article. The secondary publication is usually intended for different audiences.
What is not a duplicate publication (or prior publication by ICMJE definition– the term used for other types of releases of research results in the public)? ICMJE considers that a structured abstract under 500 words and registration of trial results in public trial registries is not a redundant publication. This means that publishing a conference abstract is not considered a publication. Presentation at a meeting (poster or a talk) are also not considered as proper publications, because they are usually not peer reviewed. Increasingly, authors post their work first in a preprint server (online research repositories) and many journals do not consider this as duplicate publication. Journals expect the authors to inform them about where the work was posted on a preprint server.
1. Fairfield CJ, Harrison EM, Wigmore SJ. Duplicate publication bias weakens the validity of meta-analysis of immunosuppression after transplantation. World J Gastroenterol. 2017 Oct 21;23(39):7198-7200.
2. COPE. Redundant publication. Accessible via: https://publicationethics.org/category/keywords/redundant-publication
3. Malički M, Utrobičić A, Marušić A. Correcting duplicate publications: follow up study of MEDLINE tagged duplications. Biochem Med (Zagreb). 2019 Feb 15;29(1):010201.
Ana Marušić contributed to this theme.
Latest contribution was May 29, 2019