US-China research collaborations continue to flourish, while UK-EU collaborations stall

The number of articles tracked by the Nature Index that were co-authored by Chinese and US researchers increased from 3,413 in 2015 to 4,631 in 2018. Data from the Nature Index also showed that Chinese authors collaborated with researchers in the US more often than any other region.

In contrast, the growth in collaborative articles between UK and EU researchers has stagnated since 2016, although collaborative articles in five leading journals (Nature, Science, PNAS, Nature Communications and Science Advances) grew by 36 percent between 2015 and 2018. The backdrop to these results and their implications are discussed in detail in the Nature Index supplement: Collaboration and big science.

In addition to data describing collaboration between countries, the latest Nature Index supplement shows how publications with thousands of authors are becoming more common. This is especially true in fields where big science projects are common, such as high-energy physics, genetics and oncology. The Nature Index data show that institutions in the US and Europe publish the largest number of multiple-author papers in these fields.

David Swinbanks, Founder of the Nature Index, said:

The fact that collaborative research continues to expand - between regions and countries with fraught political relationships - demonstrates how a collaborative approach in research is now a necessity in order to pursue pressing and global projects. Without teams with an interdisciplinary skill set and diverse perspective, it is simply not possible to tackle the increasingly complex challenges of our time.

Further Information

The Nature Index is a database of author affiliations and institutional relationships. The index tracks contributions to research articles published in 82 high-quality natural science journals, chosen by an independent group of researchers.

The Nature Index provides absolute and fractional counts of article publication at the institutional and national level and, as such, is an indicator of global high-quality research output and collaboration. Data in the Nature Index are updated regularly, with the most recent 12 months made available under a Creative Commons licence at natureindex.com. The database is compiled by Springer Nature.

The Nature Index metrics and methodology

The Nature Index provides several metrics to track research output and collaboration. These include article count (AC), fractional count (FC), and collaboration score. A country/region or an institution is given an AC of 1 for each article that has at least one author from that country/region or institution. This is the case regardless of the number of authors an article has, and it means that the same article can contribute to the AC of multiple countries/regions or institutions. FC takes into account the relative contribution of each author to an article. The maximum FC per paper is 1, and this is shared between all authors under the assumption that each contributed equally. For instance, each author on a paper with 10 authors would receive a FC of 0.1. The bilateral collaboration score (CS) between two institutions A+B is the sum of each of their FCs on the papers to which both have contributed. A bilateral collaboration can be between any two institutions or countries/regions co-authoring at least one article in the journals tracked by the Nature Index. For this supplement high affiliation articles with ten or more independent principal institutions in the authorship of the articles were isolated and then filtered into the fields of physics/astronomy; genetics; and oncology/immunology using the field of research codes of the articles in the Dimensions database of Digital Science.