Duplicate publications: attack of the clones*

From time to time, manuscripts submitted to Acta Radiologica are considered duplicates or ‘‘redundant’’ publications. A duplicate is defined by the publication of a paper that overlaps substantially with one already published, without clear, visible reference to the previous publication (1). Such duplicates should be distinguished from plagiarism, which is taking someone else’s work or ideas and passing them off as one’s own. Duplicate publication can be categorized into the following three levels: grade A, ‘‘covert duplicate publication,’’ includes studies with identical material, methods, and conclusions; grade B, ‘‘suspected or potentially duplicate publication,’’ that has almost identical material, methods, and conclusions; and Grade C, sometimes referred to as ‘‘salami-slicing,’’ has the data of the index research project separately reported in multiple publications (2). Authors are rewarded for publishing many articles and editors are rewarded for publishing them rapidly. Doctors with research ambitions are expected to carry out research with the aim of publishing several papers (3). Scientific data may be covertly published more than once due to a fearsome brew of ambitions, economic benefits, and reputation. Such unethical conduct appears to be prevalent; approximately 5% of scientists admitted they had published the same data in one or more publications during the previous 3 years (4).