Reviewer and editor biases in journal peer review: an investigation of manuscript refereeing at Angewandte Chemie International Edition

This study examined the peer review process at the journal Angewandte Chemie International Edition - the referees' recommendations and the editors' decisions to accept or reject submitted manuscripts for publication - for evidence of potential sources of bias. To analyze referees' recommendations, an ordinal regression model (ORM) with a total of 3,705 reviews by 1,542 referees on 1,744 manuscripts was used. To analyze the editors' decisions, a logistic regression model (LRM) with a total of 1,745 manuscripts was used. In addition to bias variables, an indicator (measured ex-post) for the scientific impact of a manuscript was taken into account. The results of the ORMs show that the number of institutions mentioned in the Acknowledgements of a manuscript, the share of authors having institutional affiliations in Germany, the institutional address of the referee (in Germany or not in Germany), and 'author suggested a referee for the manuscript' have statistically significant effects on the referees' recommendations. The LRM shows that the number of institutions that are mentioned in the Acknowledgements and the share of authors having institutional affiliations in Germany are potential sources of bias in the editors' decisions.