How they stack up

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From all corners of the globe, researchers across the disciplines are teaming up to tackle the big questions in science. The United States is a particularly significant contributor in its partnerships.

Data analysis by Larissa Kogleck

Index metrics

Collaboration score (CS) sums the fractional count (FC) from papers with authors from both countries. Article count (AC) is the number of articles in the index that have at least one author from that country or institution. FC measures the contribution of institutions and, by extension, countries to articles in the index. Read more on page S32.

Top country collaborations

The 10 largest collaborations between two countries, by total bilateral collaboration score (CS) in 2015. Lines below the flags represent the number of institutions involved in each side of the partnerships. Lines on the left refer to the country at the base of the columns below.

Everyone’s friend

The United States is a partner in only a small portion of global collaborations, but its contribution to those partnerships is significant.

Collaborative articles

Total number of articles in the index and total number of articles involving multiple countries.

Collaborative fields

Multi-country papers in each subject area as a proportion of the total number of papers in subject areas in 2015.


The Nature Index database tracks the affiliations of high-quality natural science articles, and charts publication productivity for institutions and countries. Article count (AC) includes the total number of affiliated articles. Weighted fractional count (WFC) accounts for the relative contribution of each author to an article, and adjusts for the abundance of astronomy and astrophysics papers. More details here.

Additional data