TOKYO -- China has become ranked only second to the U.S. for the quality of its scientific research, whereas Japan's standing has tumbled over the past two decades, according to a survey by the Japan Science and Technology Agency (JST).
In the study, which assesses countries by their volume of high-quality articles published in 151 science and technology fields between 2015 and 2017, China emerged at the top in 71 fields. The remaining 80 spots were filled by the U.S., cementing the two as the premier research nations. Conversely, Japan's research showed a clear decline over 20 years.
JST's survey equated an article's quality with its notability by measuring the frequency that other articles cite it. Using Dutch research publisher Elsevier's essay database, the team analyzed the top 10% of articles with the highest average citations over the 2015 to 2017 period.
The breakdown of the 151 fields, which excludes clinical medicine, was 46 in life sciences, 39 in engineering, chemistry and material science, 26 in computer science and math, and 40 in physics, energy and environmental science.
China leads primarily in mathematical research, which provides the basis for engineering, material science, computer science and others. Between 1995 and 1997, it only reached the Top 5 of two surveyed fields, but by the 2005 to 2007 period that number leapt to 103 fields. In the present 2015 to 2017 study, China was ranked in the Top 5 in 146 fields, almost every surveyed area. While China has made gains, the U.S. maintains the majority of top spots in life sciences.
Meanwhile, Japan's fortunes are in reverse. Twenty years ago it appeared in the Top 5 ranking in 83 disciplines, but only managed the achievement in 18 areas in the latest review period. Its best showings are third place in cancer research and in colloid surface science. Even areas where Japan has been strong in the past, such as chemistry and material science, have seen a gradual fall in citations.
Yuko Ito, senior research fellow at JST, reflected on the results, "We were surprised Japan is third in just two disciplines. It's possible that Japanese research won't be able to keep up amid the current worldwide increase in highly cited published research."
(Japanese original by Momoko Suda, Science & Environment News Department)