The effect of reviewer geographical diversity on evaluations is reduced by anonymizing submissions

Abstract

Scientists from low- and middle-income countries tend to have lower acceptance rates in academic journals than those from wealthier ones. This disparity may be partly caused by a lack of geographical diversity among peer reviewers, although rigorous evidence is lacking. We used administrative data on 205K submissions to 60 single-anonymous journals published by the Institute of Physics Publishing to measure whether reviewers favor work from their countries and whether authors from wealthier countries are more likely to be assigned to same-country reviewers (SCRs). We found that SCRs were 4.78 percentage points more likely to give a positive review compared to non-SCRs on the same manuscript. Authors from wealthier countries were up to twice as likely to be assigned to SCRs. In a sample of submissions that underwent double-anonymous review, the SCR homophily estimate was smaller and statistically similar to 0, suggesting that the homophily observed when identities are visible is an identity-based bias. Overall, authors from wealthy countries enjoy a structural advantage – they are more likely to be assigned to SCRs and receive their more favorable reviews. Diversifying the reviewer pool geographically would make acceptance rates across countries slightly more equal, likely by spreading out bias more evenly.