An analysis using automated metadata checks found that more than 10,000 papers published by PLOS and MDPI appear to violate journal conflict-of-interest policies related to prior collaborations between handling editors and authors. The findings were presented Oct. 15 at the ACM/IEEE Joint Conference on Digital Libraries and used a tool called EditorCheck. PLOS policy prohibits handling editors and manuscript authors from having coauthored within the previous five years, while MDPI sets a shorter limit of three years. The researchers, led by Jules Di Scala of the University of Toulouse, scanned metadata from published papers, then searched the Dimensions database for coauthorship relationships between editors and authors. EditorCheck flagged more than 8,000 PLOS papers and around 2,500 MDPI papers as potential policy breaches. The researchers cautioned that the presence of coauthorship does not establish whether peer review was dishonest, and noted limitations in large multi-author collaborations. PLOS’ ethics team reportedly took additional actions on cases flagged by the analysis, including reassigning some articles and adding editorial oversight; the study authors said PLOS reviewed around 100 flagged papers after being engaged by the researchers.