Impact of author characteristics on outcomes of single- versus double-blind peer review: a systematic review of comparative studies in scientific abstracts and publications

The purpose of this systematic review was to assess the role of double-blind (DB) peer review on bias against authors when compared to single-blind (SB) peer review in scientific publications. Using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, a search of databases including Pubmed, Embase, and Web of Science, without language or date restrictions, was conducted to identify original research studies comparing peer-review outcomes between DB and SB methods based on any of the following author characteristics: gender, race, geographic location, personal prestige, institutional prestige. Studies were ranked Level I, II, or III for quality of evidence based on a modified version of the Oxford Center for Evidence-Based Medicine 2011 Levels of Evidence. Of 29 studies included, five level I studies, the highest quality evidence, showed that in SB peer review, the following author characteristics were associated with more positive outcomes: male gender, White race, location of the US or North America, well-published or known in their field, or affiliation with prestigious institutions. The evidence of whether DB peer review resulted in better outcomes for authors lacking these characteristics was more discordant, possibly due to lack of effective blinding or due to unblinded editor decisions. However, if bias reduction is defined as elimination of advantages afforded to only certain types of authors, DB peer review should be considered.