02005nas a2200217   4500000000100000008004100001260001400042100001900056700002100075700001600096700002300112700001900135700001500154700001900169245006400188856005800252300001400310490000700324520144200331022001401773       2020                            d  c2020-7-061 aHelen Le Sueur1 aArianna Dagliati1 aIain Buchan1 aAnthony D. Whetton1 aGlen P. Martin1 aTim Dornan1 aNophar Geifman00aPride and prejudice – What can we learn from peer review?  uhttps://www.ncbi.nlm.nih.gov/pmc/articles/PMC7497287/  a1012-10180 v423 aObjectives: Peer review is a powerful tool that steers the education and practice of medical researchers but may allow biased critique by anonymous reviewers. We explored factors unrelated to research quality that may influence peer review reports, and assessed the possibility that sub-types of reviewers exist. Our findings could potentially improve the peer review process., Methods: We evaluated the harshness, constructiveness and positiveness in 596 reviews from journals with open peer review, plus 46 reviews from colleagues’ anonymously reviewed manuscripts. We considered possible influencing factors, such as number of authors and seasonal trends, on the content of the review. Finally, using machine-learning we identified latent types of reviewer with differing characteristics., Results: Reviews provided during a northern-hemisphere winter were significantly harsher, suggesting a seasonal effect on language. Reviews for articles in journals with an open peer review policy were significantly less harsh than those with an anonymous review process. Further, we identified three types of reviewers: nurturing, begrudged, and blasé., Conclusion: Nurturing reviews were in a minority and our findings suggest that more widespread open peer reviewing could improve the educational value of peer review, increase the constructive criticism that encourages researchers, and reduce pride and prejudice in editorial processes.  a0142-159X