According to the HKU Policy on Research Integrity (Section 2.2, ‘Publication-related conduct’):

“Publication of the same (or substantial parts of the same) work in different journals is acceptable only with the consent of the editors of the journals and where proper reference is made to the first publication. In the author’s CV such related articles must be indicated as such and not give the impression that they are distinct research outputs when they are in fact the same. Articles published in special/symposium issues should be clearly specified.”

The European Code of Conduct for Research Integrity (jointly published by the European Science Foundation and ALL European Academies (ALLEA), and to which the HKU Policy on Research Integrity makes reference) states the following (in Section 2.3, ‘Guidelines for Good Practice Rules’):

“Publication of the same (or substantial parts of the same) work in different journals is acceptable only with the consent of the editors of the journals and where proper reference is made to the first publication. In the author’s CV such related articles must be mentioned as one item.”

As stated in the passage from the HKU Policy on Research Integrity cited above, the rationale for this is to prevent researchers from giving the misleading impression in their CVs that each of their articles are distinct research outputs (when in fact they are substantially the same or very similar). Therefore, researchers would be well advised, when drafting/updating their CVs, to ensure that related articles which are not distinct research outputs are clearly indicated as such (or as one item). In addition, articles published in special/symposium issues should be clearly identified as such.