Peer reviewers sometimes comment that their own journal articles should be cited by the journal article under review. Comments concerning relevant articles can be justified, but comments can also be unrelated coercive citations. Here, we used a matched observational study design to explore how citations influence the peer review process. We used a sample of more than 37,000 peer reviews from four journals that use open peer review and make all article versions available. We find that reviewers who were cited in versions after version 1 were more likely to make a favourable recommendation (odds ratio = 1.61; adjusted 99.4% CI: 1.16-2.23), whereas being cited in the first version did not improve their recommendation (odds ratio = 0.84; adjusted 99.4% CI: 0.69-1.03). For all versions of the articles, the reviewers who commented that their own articles should be cited were less likely to recommend approval compared to the reviewers who did not, with the strongest association after the first version (odds ratio = 0.15; adjusted 99.4% CI: 0.08-0.30). Reviewers who included a citation to their own articles were much more likely to approve a revised article that cited their articles compared to a revised article that did not (odds ratio = 3.5; 95% CI: 2.0-6.1). Some reviewers' recommendations depend on whether they are cited or want to be cited. Reviewer citation requests can turn peer review into a transaction rather than an objective critique of the article.

Suggesting fake peer reviewers can happen when journals invite authors to recommend a list of suitable peer reviewers, along with their contact information Scientific misconduct is the violation of ethical and professional standards in research, including fabrication, falsification, plagiarism, and other practices that compromise the integrity of the design, conduct, analysis, reporting, or publication of scientific or research findings. A reviewer or editor with a conflict of interest can coerce the author to cite the reviewer's publications prior to recommending publication. This can inflate the perceived citation impact of a researcher's work and their reputation in the scientific community, similar to excessive self-citation. Suggesting fake peer reviewers can happen when journals invite authors to recommend a list of suitable peer reviewers, along with their contact information. In some cases, authors have recommended a "reviewer" for whom they provide a fake email address that in fact belongs to the author. If the editor follows the author's reviewer recommendation, the author can then write their own review. A rarer case of scientific misconduct is editorial misconduct, where an editor does not declare conflicts of interest, creates pseudonyms to review papers, gives strongly worded editorial decisions to support reviews suggesting to add excessive citations to their own unrelated works or to add themselves as a co-author or their name to the title of the manuscript.