THE EFFECTS OF BLINDING ON ACCEPTANCE OF RESEARCH PAPERS BY PEER-REVIEW

Objective.-To study whether reviewers aware of author identity are bia sed in favor of authors with more previous publications. Design.-Rando mized controlled trial. Setting.-Editorial office of the Journal of De velopmental and Behavioral Pediatrics. Participants.-Two ''blinded'' a nd two ''nonblinded'' reviewers assigned to 57 consecutive manuscripts submitted between September 1991 and March 1992. Outcome Measures.-Sp earman rank correlation coefficients were used to compare the sum of r ating scores of 1 to 5 (1, accept; 5, reject) given by the two blinded reviewers, the two nonblinded reviewers, and the editors to the numbe r of articles published previously by the first and senior authors (as determined from requested curricula vitae). Blinded reviewers were se nt a questionnaire asking whether they could determine the identity of the authors, how they knew, and whether they thought blinding changed the quality or difficulty of their review. Results.-The Wilcoxon Sign Rank Test disclosed no differences between blinded and nonblinded sco res. The number of previous articles by the senior author was signific antly correlated (P<.01) with blinded scores (r=-.45) and editors' dec isions (r=-.45), but not with nonblinded scores; the number of article s by the first author was correlated (P<.05) with editors' decisions ( r=-.35) but not with blinded or nonblinded scores. Fifty (46%) of 108 blinded reviewers correctly guessed the identity of the authors, mostl y from self-references and knowledge of the work; 86% believed blindin g did not change the quality of their review, and 73% believed it did not change the difficulty of performing a review. Conclusions.-Blinded reviewers and editors in this study, but not nonblinded reviewers, ga ve better scores to authors with more previous articles. These results suggest that blinded reviewers may provide more unbiased reviews and that nonblinded reviewers may be affected by various types of bias.