As part of its Science & Engineering Indicators series, the National Science Board has published the report "Publications Output: U.S. Trends and International Comparisons." The report was prepared by NSF's National Center for Science and Engineering Statistics.
Over 44 million articles published from 1996 to 2020 are analyzed. The articles include conference papers and research articles (collectively referred to as articles) published in conference proceedings and peer-reviewed scientific and technical journals. The articles exclude editorials, errata, letters, and other material that do not typically present new scientific data, theories, methods, apparatuses, or experiments. The articles also exclude working papers and preprints, which are not generally peer reviewed yet.
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).
The report presents data on research publication output by country, scientific field, international collaboration, and impact measures. The first section examines comparative country data on publication output across science and engineering (S&E) fields. It also includes two sidebars: (1) publications by members of underrepresented groups and the impact on the research and development (R&D) workforce, and (2) measuring cross-disciplinary publication output. The second section focuses on collaboration between researchers in the United States and other regions, countries, and economies through examining coauthoring and citation patterns. This section includes a sidebar on the 2020 coronavirus publication output and collaboration network. The third section provides an analysis of scientific impact as measured by citations in research publications.
The analysis reported here is based on counting publications and citations using bibliometric data in Scopus, a database of scientific literature with English-language titles and abstracts (Science-Metrix 2021a). There are benefits and limitations to counting publications and citations using bibliometric data as an indicator of research output. A benefit is that this approach provides comparable information for analyzing research output across countries. A potential limitation is that country-specific incentive payments for academic publications are not considered (Franzoni, Scellato, and Stephan 2011). Additional limitations are the lack of measurement for the amount of research contained in each article and the contributions of associated data sets (Sugimoto and Larivière 2018).
Articles with authors working in multiple countries are used for both counting publication output by country and for determining international collaborations. The country is determined by the institutional address of each author as listed in the article. For counting country output, each country receives a fractional contribution based on the number of authors. For determining international collaboration, each country or region represented by one or more authors is counted once. Because whole counting is used for international collaboration and fractional counting is used for publication output, those values are not directly comparable.
Assignment of articles to S&E fields uses the 14 fields of science in the National Center for Science and Engineering Statistics (NCSES) Taxonomy of Disciplines (TOD) (Science-Metrix 2019).
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.
Link to report: https://ncses.nsf.gov/pubs/nsb20214/executive-summary