One of the conundrums of peer review is that reviewers need to be knowledgeable about the research being reported but shouldn’t have conflicts of interest. The trouble is that the best-qualified people are often too closely connected to either the research or the authors. This problem is amplified in small research fields and for journals publishing in languages that not many people speak. While it’s fairly easy to find an English-speaking cardiologist completely unconnected to a trial and its authors, it’s far more tricky to find, let’s say, an expert on Mediterranean fish stocks who can review articles in Croatian.

I review for several journals on the relatively little-studied area of peer review and publication ethics. This small research field gets published in a funny mix of journals (including ones on clinical medicine, ethics, and information science) so I get review requests from a wide range of journals. Over the years, I’ve noticed that these journals have different policies on how much of a conflict of interests is too much for a reviewer. So, if I point out to some editors that I have co-published with one of the authors a few years ago, one editor may say that’s not a problem, while other journals will immediately say they don’t want me to review in that case.

I reckon (but without any data or systematic study to prove it) that highly selective journals (i.e. those with high rejection rates, which also tend to have high impact factors and therefore to be regarded as “prestigious”) have more stringent policies than the so-called mega-journals that aim to publish all sound science. (The BMJ Editors will probably howl at me that The BMJ and BMJ Open operate identical policies, but you know what they say about exceptions proving the rule.) Thinking about it, this may make sense, as these two types of journal are using peer review for different functions. If you are advising a journal about whether an article should be published, and if publication in that journal is viewed as a big prize by authors (and their institutions), then your potential to improve or damage the authors’ careers (or the sponsor’s profits) is greater than if you are only suggesting ways to improve the article, and the journal’s default position is to publish it.

Then there is the question of whether the peer review is anonymous or signed, and whether the reviewer is told the author’s identity. If I’m not told a submission is from a deadly rival (and I can’t reasonably be expected to guess who the authors are), perhaps this rivalry doesn’t matter? If the review is published alongside the article so readers can judge the fairness of the comments, does this reduce the potential harm of reviewers’ competing interests (at least for accepted articles)? Or, if the journal is enlightened enough to blind reviewers to the findings (so they comment on the soundness of the methods without seeing the results) then maybe the need to worry about conflicts of interest shrinks even further (but never disappears entirely—nobody should be asked to review the work of their children or partner).

To be honest, I’m not sure if we should be worried if journals use different criteria for disqualifying peer reviewers, but it might be good if journals published their policies so readers, authors, and potential reviewers could see them. Or maybe we need debate and then a guideline on this (as you may know, I love guidelines)—but we’d have to be careful who we asked to review it.

Liz Wager PhD is a freelance medical writer, editor, and trainer. She is co-editor-in-chief of Research Integrity & Peer Review. She was the chair of the Committee on Publication Ethics (COPE) (2009-2012).

Competing interests: The author has no further relevant interests to declare.