- Global research output, as measured by peer-reviewed science and engineering (S&E) journal articles and conference papers, grew about 4% annually over the last 10 years.
- China’s rate of research output has grown almost twice as fast as the world’s annual average for the last 10 years, while the output of the United States and European Union (EU) has grown at less than half the world’s annual growth rate.
- Research papers from United States and EU countries continue to have the most impact; however, China has shown a rapid increase in producing impactful publications, as measured by references to journal articles and conference papers.
- Specialization in scientific fields differs among countries, with the United States, the EU, and Japan more specialized in health sciences and China and India more specialized in engineering, as measured by journal articles and conference papers.
- International collaborations have increased over the last 10 years.
Data on articles in peer-reviewed S&E journals and conference papers reflect the rapidly expanding volume of research activity and the new knowledge it generates, the growing involvement and scientific capabilities of middle-income countries, and the expanding research ecosystem demonstrated through international collaborations. A primary method of disseminating research is through publication of articles in peer-reviewed journals and conference proceedings. This report utilizes data from the Scopus database of global S&E publications and finds that worldwide S&E publication output continues to grow on average at nearly 4% per year; from 2008 to 2018, output grew from 1.8 million to 2.6 million articles. In 2018, China (with a share of 21%) and the United States (with a share of 17%) were the largest producers. As a group, the EU countries (with a share of 24%) produced more S&E articles than China or the United States.
The international nature of research continues to grow. International collaborations increased in 2018 with slightly more than one out of five articles having coauthors from multiple countries. The collaboration base has grown as countries that were small producers of scientific publications 10 to 20 years ago have accelerated their global publication output.
Scientific impact, as measured by highly cited publications, shows the United States is among the leading countries with close to twice as many citations as would be expected given U.S. production levels. The U.S. impact in S&E publications has remained steady over the last 20 years.
The articles published from the United States and the EU countries exhibit relatively more specialization and impact in the fields of astronomy and astrophysics, biological and biomedical sciences, geosciences, health sciences, psychology, and social sciences. The EU countries also show specialization and impact in natural resources and conservation as well as mathematics and statistics. China’s publications show the most specialization and impact in the fields of agricultural sciences, chemistry, computer and information sciences, engineering, materials science, natural resources and conservation, and physics.