Differences between Single-Blind and Double-Blind Peer Review

In single-blind peer review, only the reviewers are anonymous. Reviewers know the authors’ names and backgrounds, but authors don’t know those of the reviewers.

In double-blind peer review, both the authors and reviewers keep their anonymity. Only the editor knows the identity of all parties involved.

Why are single-blind and double-blind review preferred?

In contrast to open peer review, where authors know the identity of their reviewers and vice versa, reviewers are always anonymous in single and double-blind peer review. The differences come from the added anonymity of the author in double-blind peer review.

Advocates of double-blind peer review argue that it goes further towards reducing the possibility of bias in the peer review process. Anyone capable of reviewing a manuscript will be an expert in that manuscript’s subject area, and therefore may have a conflict of interest. Hiding the identity of the author prevents the reviewer’s objectivity being compromised by personal feelings or professional motivations.

Avoiding biases in the review process

There is also more general bias to consider. Discrimination based on gender^[1] and race^[2] is not unheard of in academia, despite the high value placed on objectivity, and some studies have shown that double-blind peer review can help to avoid this.^[3] Keeping the authors’ affiliations confidential can also help prevent reviewers being influenced by reputation. For example, a reviewer may review a paper from Harvard University more favourably than a comparable paper from a less prestigious institution, or perhaps they might give more leeway to a respected subject leader than a young academic who has yet to establish themselves.

Other points to consider regarding peer reviews

Of course, double-blind peer review is not without its downsides.

It can be difficult to ensure a fully anonymous review. Not only must all personal information and metadata be removed from the submitted manuscript, but authors must make sure that any references to their previous work do not reveal their identity to peer reviewers, who are likely to have prior knowledge of the research and researchers involved in their field. Some editors also worry that the power of search engines makes true author anonymity difficult to achieve.^[4]

Single-blind peer review can also be more effective at identifying self-plagiarism and conflicts of interest.^[5] When an author is known to a reviewer only by an arbitrary reference number, how can the reviewer be expected to know, for example, that the manuscript under review borrows heavily from previous work, or reports on an organization by which the author is paid a consulting fee? Unless declared by the author, possible ethical considerations like these may go unnoticed until publication, resulting in the potential for subsequent retraction.