Background: Researchers are increasingly accessing scientific articles through unauthorized websites like Sci-Hub. Sci-Hub contains retracted articles, including those which are not labelled as retracted, and this is a potential threat to academic research.
Methods: This study analyses the extent of the availability of retracted articles within the Sci-Hub, particularly focusing on the presence of unlabeled retracted articles (URA) which may inadvertently be used in subsequent research, thus propagating flawed findings. The authors identified 16925 English-language research articles retracted between 2003 and 2022 indexed in the Web of Science and Scopus databases. These articles were cross-checked with Sci-Hub to ascertain whether they were appropriately labelled as retracted.
Results: The investigation revealed that 84.83% of the retracted articles available on Sci-Hub do not have any indication of their retracted status. These URA could potentially be reused by researchers, unaware of their retracted status. The availability of URA in the field of health sciences is particularly high, which indicates a significant risk of their unintended use and further citation in future research.
Conclusions: This study underscores the crucial need for stringent implementation of regulatory measures on retraction suggested by the Committee on Publication Ethics (COPE) or newly published National Information Standards Organization (NISO) recommendations.
Keywords: Academic publishing; article retraction; post-retraction citations; research integrity; scholarly communication.