Context.— Anxiety about bias, lack of accountability, and poor quality of peer
review has led to questions about the imbalance in anonymity between reviewers
Objective.— To evaluate the effect on the quality of peer review of blinding reviewers
to the authors' identities and requiring reviewers to sign their reports.
Design.— Randomized controlled trial.
Setting.— A general medical journal.
Participants.— A total of 420 reviewers from the journal's database.
Intervention.— We modified a paper accepted for publication introducing 8 areas of
weakness. Reviewers were randomly allocated to 5 groups. Groups 1 and 2 received
manuscripts from which the authors' names and affiliations had been removed,
while groups 3 and 4 were aware of the authors' identities. Groups 1 and 3
were asked to sign their reports, while groups 2 and 4 were asked to return
their reports unsigned. The fifth group was sent the paper in the usual manner
of the journal, with authors' identities revealed and a request to comment
anonymously. Group 5 differed from group 4 only in that its members were unaware
that they were taking part in a study.
Main Outcome Measure.— The number of weaknesses in the paper that were commented on by the
Results.— Reports were received from 221 reviewers (53%). The mean number of weaknesses
commented on was 2 (1.7, 2.1, 1.8, and 1.9 for groups 1, 2, 3, and 4 and 5
combined, respectively). There were no statistically significant differences
between groups in their performance. Reviewers who were blinded to authors'
identities were less likely to recommend rejection than those who were aware
of the authors' identities (odds ratio, 0.5; 95% confidence interval, 0.3-1.0).
Conclusions.— Neither blinding reviewers to the authors and origin of the paper nor
requiring them to sign their reports had any effect on rate of detection of
errors. Such measures are unlikely to improve the quality of peer review reports.