KEY TAKEAWAYS

• Single blinding in peer review may be subject to unconscious bias, putting authors from wealthier, English-speaking countries at an advantage.
• Double blinding can improve equity in peer review and even increase reviewer numbers, thus creating a more time-efficient process.

The shortfalls of the current peer review process have long been debated. Now, a real-life experiment conducted by a journal’s own editorial team leads them to call time on the traditional single-blind peer review system, in favour of a more equitable double-blind approach.

How does double-blind review improve equity?

Writing in a post on the LSE Impact Blog, Professor Charles Fox (Executive Editor of the journal in question, Functional Ecology, at the start of the experiment), explained his team’s conclusions that:

Authors from wealthy countries and those with higher levels of English language proficiency receive an advantage under current peer review processes.

In the study, around 3,700 papers submitted to the journal over a period of 3 years were randomly assigned to either single-blind (ie, only the reviewer was anonymous) or double-blind (ie, reviewers and authors were anonymous) peer review. The group found that:

• single blinding can be subject to positive biases relating to the country of origin of authors
• authors from wealthier, English-speaking countries received higher scores and were more likely to be invited to proceed to the revisions stage, when their identities were known
• no biases were identified in relation to gender.

As a result of the experiment, all peer review at Functional Ecology is now double blind.

What are the challenges with double-blind review?

Prof. Fox acknowledges that concerns exist around potential costs and limitations associated with double blinding, and that there is a generally held assumption that individuals would be less keen to review under such a system. The group, however, found the reverse to be true, with double blinding leading to increased reviewer numbers and a more time efficient process.

Issues can also arise in maintaining the anonymity of authors, for a number of reasons:

• Individuals can be recognisable to their peers because of their specialism, research methods, etc.
• Manuscripts may have been previously submitted to a preprint server or earlier data published as part of a longer-term trial.

Sixty percent of reviewers in the study stated that they knew, or suspected, the identity of authors despite anonymisation, and in 90% of these cases they were correct.

What is the best way forward?

While the study’s findings reinforce existing evidence that unconscious bias exists within peer review, single blinding is still standard practice for most journals. Some offer optional anonymisation (ie, authors can choose whether to be identified), but Prof. Fox argues that this does not go far enough. In an ‘opt in’ system, authors from more affluent countries – who are more likely to benefit from positive bias – would perhaps be unlikely to hide their identity.

Overall, Prof. Fox maintains that any potential challenges associated with double blinding do not outweigh the benefits of improved objectivity. He calls on journals to follow Functional Ecology’s example and make the switch to mandatory double-blind peer review.

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