Does masking author identity improve peer review quality? A randomized controlled trial. PEER Investigators

All authors may not be equal in the eyes of reviewers. Specifically, well-known authors may receive less objective (poorer quality) reviews. One study at a single journal found a small improvement in review quality when reviewers were masked to author identity.

To determine whether masking reviewers to author identity is generally associated with higher quality of review at biomedical journals, and to determine the success of routine masking techniques.

A randomized controlled trial performed on external reviews of manuscripts submitted to Annals of Emergency Medicine, Annals of Internal Medicine, JAMA, Obstetrics & Gynecology, and Ophthalmology.

Two peers reviewed each manuscript. In one study arm, both peer reviewers received the manuscript according to usual masking practice. In the other arm, one reviewer was randomized to receive a manuscript with author identity masked, and the other reviewer received an unmasked manuscript.

Review quality on a 5-point Likert scale as judged by manuscript author and editor. A difference of 0.5 or greater was considered important.

A total of 118 manuscripts were randomized, 26 to usual practice and 92 to intervention. In the intervention arm, editor quality assessment was complete for 77 (84%) of 92 manuscripts. Author quality assessment was complete on 40 (54%) of 74 manuscripts. Authors and editors perceived no significant difference in quality between masked (mean difference, 0.1; 95% confidence interval [CI], -0.2 to 0.4) and unmasked (mean difference, -0.1; 95% CI, -0.5 to 0.4) reviews. We also found no difference in the degree to which the review influenced the editorial decision (mean difference, -0.1; 95% CI,-0.3 to 0.3). Masking was often unsuccessful (overall, 68% successfully masked; 95% CI, 58%-77%), although 1 journal had significantly better masking success than others (90% successfully masked; 95% CI, 73%-98%). Manuscripts by generally known authors were less likely to be successfully masked (odds ratio, 0.3; 95% CI, 0.1-0.8). When analysis was restricted to manuscripts that were successfully masked, review quality as assessed by editors and authors still did not differ.

Masking reviewers to author identity as commonly practiced does not improve quality of reviews. Since manuscripts of well-known authors are more difficult to mask, and those manuscripts may be more likely to benefit from masking, the inability to mask reviewers to the identity of well-known authors may have contributed to the lack of effect.