w reviewer homophily. These analyses leverage data from 31 studies, which cumulatively examined 312,740 manuscripts submitted to >640 journals-including Nature Portfolio journals, Science and Proceedings of the National Academy of Sciences. Our dataset represents 4,529,971 author position/demographic/review stage interactions, which upon publication will be the largest publicly available dataset of this kind for future work to build upon. Finally, we describe the current landscape of peer review in the subfields of ecology and evolution by collecting peer review policy data from the websites of 541 journals. Altogether, we find that author demographics predict review outcomes; clear, evidence-based solutions to alleviate review bias are lacking; and relatively few journals are pro-actively combatting bias.
Results and discussion
Disparate peer review outcomes by author demographicsWe found evidence for disparate peer review outcomes for all demographics that we examined at one or more stages in the review process (Supplementary Tables 3-40). We found the most data on outcomes by author assumed gender (Supplementary Data 1). Assumed female authors had worse or similar outcomes compared with assumed male authors, depending on the author position and review stage (Fig. 2).We found notably lower success throughout the review process for authors with institutional affiliations in Asia, in countries where English is not a primary language and in countries with lower Human Development Indices (HDI; Figs. 2 and 3). Compared with authors with affiliations located in Europe, North America and Oceania, authors with affiliations located in Asia had the most consistent disparities, but authors in Latin America and Africa also often had worse review outcomes. When considering a country's continent, language and HDI