Affiliation homogeneity and scientific impact: A comparative study across nations

The crucial role of affiliation diversity in driving scientific progress is widely recognized. However, existing research did not distinguish international and domestic collaborations, overlooking the specific impact of domestic affiliation diversity on scientific breakthroughs. In this study, we utilize the Microsoft Academic Graph (MAG) dataset from 2000 to 2020 and apply the Shannon entropy to quantify diversity. While our findings indicate that domestic affiliation diversity has increased over the past two decades, contemporary science still exhibits a high level of affiliation homophily. Notably, China’s affiliation diversity remains low across different team sizes and scientific fields compared to other countries. Additionally, we observe a positive correlation between domestic affiliation diversity and citation impact in the U.S., the U.K., and Japan, with larger teams benefiting more significantly. In contrast, in China, there is a significant negative correlation between affiliation diversity and citation impact. Additionally, we find that in Chinese publications, the majority of contributions, conditional on affiliation diversity, come from a single institution. Our research sheds light on the relationship between domestic affiliation diversity and citation impact. These findings may have important policy implications for strengthening national research capabilities.