As countries get richer, they get better at doing science. It should come as no surprise, then, that China is rising as a scientific power. What is surprising, though, is just how quickly the country is doing it. According to new research, China’s share of global scientific output now far exceeds its share of global economic output.

The study, published by Qingnan Xie of Nanjing University and Richard Freeman of NBER, argues that the world has been underestimating China’s contribution to science. So far, the way country-level contributions are measured is based on how many scientific papers have authors with an address in a particular country. But the new study argues that using addresses does not account for cases in which, for instance, Chinese researchers author a paper while working at a US university.

Correcting for those sorts of mistakes, the authors find that Chinese researchers now publish more scientific papers than others. Roughly one in four scientific papers published has an author with a Chinese name or address. If Chinese-language papers are included, then the figure jumps up to 37%. By comparison, China contributes around 15% to global GDP.

Critics point out that the volume of papers alone isn’t enough. Many of these papers are published in lower-quality journals and thus don’t make an equal contribution to scientific progress as studies published in top outlets. But Xie and Freeman show that the quality of Chinese science has also been on the rise.

One way to measure quality is to look at how many other scientific papers cite a paper of Chinese origin. In 2000, papers with all-Chinese addresses received around 30% of the world average of citations, “implying that those papers had little impact on research worldwide,” the authors write. By 2013, citations to papers with all-China addresses increased to 70% of the global average. Another way to measure improving quality is to look at China’s share of global citations, which rose from 7.4% in 2000 to 19.5% in 2013.

The quality of China’s research can also be measured by its contribution to the world’s top-tier journals: Science and Nature. In both cases, the growth between 2000 and 2016 is astonishing.

“That China, one of the lowest income countries in the world at the turn of the 21st century, became a super-power in scientific knowledge in less than two decades is a remarkable development in the history of science.” the authors conclude. “To paraphrase… advice to Americans as the US expanded to California ‘Go West, young man, and grow up with the country,’ barring some huge massive change, science is going East and will grow up with China.”

To be sure, the study is only a working paper. It has yet to go through a process of peer review. For instance, to account for Chinese author contributions, Xie and Freeman assumed that anyone with a traditional Chinese first name and last name is from China (because many Chinese abroad take on a Western first name). If that assumption doesn’t stand scrutiny, it could reduce China’s contributions to global science.

This article was updated to explain the assumption the study authors made to include the contribution of Chinese authors based abroad.