Key takeaways:

• The United States remains a highly influential nation in science and engineering (S&E) research as measured by the volume of conference papers and peer-reviewed journal articles and the citations to those publications.
• The high-income economies (including the United States, the United Kingdom, Germany, France, and Japan) have steadily increased their large base of S&E publications, while lower-middle-income and upper-middle-income economies (including India and China) have rapidly increased production starting from a lower base of S&E publications in 1996.
• In 2016, China exceeded the publication output of the United States; in 2017, India became the third-largest producer.
• Beginning in 2017, articles from China received citations above the number expected, given the number of articles they produced.
• U.S. researchers have increased international collaboration over the last 15 years. Authors with an institutional address in China are the most frequent coauthors with authors whose institutional address is in the United States. In addition, the international citations by authors, whose institutional address is in the United States, most often cite authors with institutional addresses in the United Kingdom, Canada, and Australia.
  
• In 2020, major research countries—the United States, China, the United Kingdom, and many European Union countries—were hubs of global coronavirus research collaboration.

The primary method of disseminating research findings is through publication of conference proceedings and peer-reviewed journal articles (i.e., publication output). Data on publication output indicate an increase in global research activity, a growth in the involvement and scientific capabilities of middle-income countries, and an internationally connected research ecosystem.

Publication output reached 2.9 million articles in 2020, based on data from the Scopus database of S&E publications. The countries with the largest volume of S&E publications in 2020 were China, with 23% of global output, and the United States, with 16%. The compound annual growth rate of publication output has increased in recent years. The rate was 5% over the last 4 years (2017 to 2020) but was 4% over the longer 11-year period (2010 to 2020).

Internationally collaborative research continues to grow. International collaborations increased in 2020, with nearly one in four articles having coauthors from multiple countries as compared to one in seven in 2000. Collaboration on articles has also grown among relatively small producers, such as Saudi Arabia, Pakistan, and Argentina.

Data on article citations show that the United States and other nations, such as the United Kingdom, the Netherlands, and Switzerland, are among the countries producing highly impactful research papers. The impact of U.S S&E articles has remained steady over the last 24 years, while highly cited articles from China grew dramatically.