A published paper in Journal A, focusing on a cohort of patients with an uncommon respiratory pathogen, raises concerns as a similar paper had been published in a US journal (Journal B) a few months earlier. The latter paper included a slightly expanded patient cohort and provided additional secondary outcome data but reached similar conclusions. While the editor of Journal A perceives this as a case of duplicate publication, the authors argue against it, emphasizing the inclusion of additional data.
COPE Advice: The Committee on Publication Ethics (COPE) provides guidance on this complex issue. It suggests that journals should clearly outline rules regarding duplicate publication in their instructions to authors or submission guidelines. Some journals even require authors to submit related papers during the initial submission process. COPE participants propose a practical rule of thumb: if the additional data cannot stand alone and significantly contribute to the research, it is likely duplicate publication.
Given the complexity, COPE advises leaving the decision to the editor's judgment. In cases where duplicate publication is suspected, a correction should be published in both journals. The use of plagiarism detection software is recommended to identify overlap between papers. Detecting and addressing such issues is crucial to prevent the inflation of data in meta-analyses when undetected.
Follow-Up: In this specific case, the editor communicated to the authors that the situation was considered a case of duplicate publication, leading to the withdrawal of the paper from Journal A's website. A notice of duplicate publication was then published in Journal A to transparently address the issue.