Blinding of Peer Review and the Impact on Geographic Diversity of Authors in the Medical Literature

BACKGROUND: Blinding of reviewers is hypothesized to improve the peer review process by removing potential bias. This study aimed to evaluate the impact of blinding of peer review on the geographic diversity of authors in medical/clinical journals. METHODS: MEDLINE-indexed medical journals were evaluated, where journals that only publish in basic sciences or administration, non-English journals, journals that publish solely solicited materials, and journals that employ open review process were excluded. Journals were divided into single-blinded or double-blinded. Diversity was calculated by dividing the number of countries from which 20 evaluated articles come and multiplying by 100 (%diversity). The second method involved calculating Simpson’s diversity index (SDI). RESULTS: Of 1054 journals, 766 employ single-blinded review and 288 were double-blinded. Journals had a median age of 28 years and were mostly international (n=355 single-blinded and 97 double-blinded). No difference was observed between the two groups in median %diversity (45 in both groups; P=0.199) and SDI (0.84 vs 0.82; P=0.128). The indexing of journals in Science Citation Index Expanded (SCIE) collection of Web of Science and Scopus, and a higher CiteScore were significantly associated with higher %diversity and SDI (P<0.05). CONCLUSION: Although double blinding of peer review was not associated with higher geographic diversity of authors, several factors are also involved in the review process that could not be evaluated, such as blinding of editors. However, editors and publishers are encouraged to consider work from different countries to be able to index their journals in SCIE, Scopus, and MEDLINE where geographic diversity is a requirement.