This section of the report outlines trends over time in publication output across regions, countries, or economies and by fields of science. This section also provides insights into the research contributions of different regions, countries, or economies and how the focus of their scientific publications has changed over time. In addition, the section highlights variations in the distribution of publications across scientific fields for different regions, countries, or economies and examines trends over time in closed-access and open-access (OA) publications. This section also summarizes federal funding acknowledgments as a source of data to shed light on published research that received federal funding. (See sidebar Using Funding Acknowledgments to Track Federally Funded Research Over Time.)

Total worldwide S&E publication output reached 3.3 million articles in 2022, based on entries in the Scopus database.^{​Publication output includes only those indexed in the Scopus database. The publication output discussion uses fractional counting, which credits coauthored publications according to the collaborating institutions or regions, countries, or economies based on the proportion of their participating authors. Country assignments refer to the institutional address of authors, with partial credit given for each international coauthorship. As part of the data analysis, filters were employed on the raw Scopus S&E publication data to remove publications with questionable quality, which appear in what are sometimes called predatory journals (NSB Indicators 2018: Bibliometric Data Filters).} Approximately 86% of publications in 2022 came from regions, countries, or economies with high-income and upper-middle-income economies (Figure PBS-1). The number of publications from all income-level groups grew between 2003 and 2022 (Table SPBS-2). Also, the number of publications from upper-middle-income economies grew more quickly than the number from high-income economies during the more recent period between 2010 and 2022.

In 2022, six regions, countries, or economies each produced more than 100,000 articles: China, the United States, India, Germany, the United Kingdom, and Japan. Together, these leading regions, countries, or economies accounted for over 50% of the worldwide total in 2022 (Figure PBS-2; Table PBS-1).^{​The proportion of output attributable to the large producers is consistent whether using fractional counting, as in Figure PBS-2 and Table PBS-1, or whole counting, as in Table SPBS-17. There is a slight difference between the United States and China when looking at the whole-counting total production numbers. Using whole counting for 2022, the United States had 605,633 articles, whereas China had 976,141. A whole-counting measure allocates one full count to each region, country, or economy with an author contributing to the article; in fractional counting, each region, country, or economy receives a proportion of the count based on the number of authors from that region, country, or economy. For example, if an article had four authors—two from the United States, one from China, and one from Brazil—the fractional scores would be half for the United States, a quarter for China, and a quarter for Brazil. The difference between whole and fractional counting indicates that the United States has more authors working with Chinese authors than China has working with U.S. authors.} In absolute numbers, the growth in worldwide annual publication output (from 2.0 million in 2010 to 3.3 million in 2022) was driven in particular by two countries: China (42% of additional publications during that period) and India (11%) together accounted for more than half of that increase in publications (Figure PBS-3). Russia, South Korea, Iran, and Brazil made notable contributions to the growth in the number of publications from the rest of the world from 2010 to 2022 (Figure PBS-3; Table SPBS-2). Generally, the set of the top 15 producers of S&E articles was the same each year between 2010 and 2022, with the exception of Iran replacing Taiwan in the top 15 beginning in 2014 (Table PBS-1; Table SPBS-2).

The U.S. trend of moderate but increasing publication output varied by state. The National Science Board’s (NSB’s) State Data Tool (https://ncses.nsf.gov/indicators/states/) provides state-level data based on each state’s doctorate population and research and development (R&D) funding. Indicators include academic S&E article output per 1,000 science, engineering, and health doctorate holders in academia (NSB 2021a) and academic S&E article output per $1 million in academic S&E R&D funding (NSB 2021b).

The distribution of publications by field of science across region, country, or economy may indicate research priorities and capabilities. Health sciences was the field of science in which most articles were published in 2022, representing almost a quarter of all publications (Table SPBS-2 and Table SPBS-10). Other fields with large numbers of publications included engineering (17% of publications in 2022), biological and biomedical sciences (13%), and social sciences (5%) (Table SPBS-2, Table SPBS-5, Table SPBS-8, and Table SPBS-16). In the United States, the European Union (EU-27), and Japan, health sciences publication output in 2022 far exceeded that of any other field.^{​The use of whole counting or fractional counting to tally the publication output of nations can change the calculated publication count based on the degree to which a region, country, or economy is involved in international collaborations. Under whole counting, a nation receives credit for any publication with an author from that nation. Under fractional counting, the nation’s credit for a publication is prorated based on the share of the publication’s coauthors who are located in that nation (Table SPBS-17 through Table SPBS-31).} Meanwhile, of the other top producers, publications from China were most highly concentrated in engineering (25%), and publications from India were published predominantly in computer and information sciences (21%) (Figure PBS-4).

Fields within life sciences were dominant in the United States in 2022, with more than half of all U.S. publications in health sciences (37%) or biological and biomedical sciences (14%) (Figure PBS-5). There were fewer U.S. publications in engineering (11%), computer and information sciences (7%), and physics (5%). In comparison with the United States, China had a stronger focus on publications in engineering and in the physical sciences and information sciences. In 2022, 25% of China’s publications were in engineering, 11% were in computer and information sciences, and 9% were in physics (Figure PBS-6). Compared with the United States, China had a lower percentage of its publications in health sciences (14%) and biological and biomedical sciences (12%). In 2022, China also had a much lower percentage of its publications in social sciences (1%) when compared with the United States (8%).

All the leading regions, countries, or economies saw an increase in their output of health sciences publications between 2010 and 2022. This increase is to be expected, given the context of increasing publication rates in general over that period, with overall number of publications increasing by 71% (Table SPBS-2), while publications in health sciences increased by 66% (Table SPBS-10). Russia had the highest relative growth rate among the 20 leading regions, countries, or economies in health sciences, increasing its publication output by almost 450% between 2010 and 2022 (Table SPBS-10). China and Iran each increased their output of health sciences publications by more than 250% over this period, while India’s health sciences publication output increased by more than 180%. The United States increased its output of health sciences publications by 32% over this period, while Germany, France, the United Kingdom, and Japan had the smallest increases, each with less than 20%.

Leading regions, countries, or economies also saw increases in engineering publications. The fastest growing between 2010 and 2022 were India (up 378%) and Russia (up 230%) (Table SPBS-8). China increased its output of engineering publications by 176% from 2010 to 2022, while France, the United States, and Japan all saw declines in newly published engineering articles per year over this period (3%, 13%, and 26%, respectively).

In the United States, publication output varied from that of other regions, countries, or economies with respect to scientific fields. Of the fields not already mentioned, the fastest growing from 2010 to 2022 were psychology (up 39% from 2010 to 2022) and the social sciences (up 38%) (Figure PBS-7). Meanwhile, fields with the largest decreases in U.S. publications included physics (down 31% from 2010 to 2022) and materials science (down 16%).

There is growing support for the availability of S&E publications through OA sources among government and private funders, institutions, and scientists themselves. Some of these funders have imposed requirements on their grantees to publish their research results in OA journals. In the United States, the Office of Science and Technology Policy announced that all federal agencies should update their public access policies as soon as possible to ensure that results of their funded research are publicly available, with full implementation of these policies by the end of 2025 (Brainard and Kaiser 2022). Meanwhile, restricted access to scientific literature may impede researchers’ ability to stay informed (Larivière and Sugimoto 2018; Piwowar et al. 2018). As alternatives to traditional closed-access journals (where readers must subscribe to gain access or pay per article), articles may be made OA through several avenues, with different levels of availability and durability.

There are four commonly defined types of OA: Gold, Hybrid, Bronze, and Green. Gold OA denotes articles published in journals that are entirely OA as a matter of journal policy. Hybrid OA denotes articles for which the authors have elected to pay a fee for publication as OA rather than as closed access. Bronze OA denotes articles that appear as OA after an embargo period of closed access or articles that appear available as OA despite lacking license information to guarantee OA in the long term. Green OA denotes articles that are self-archived by authors in OA repositories, which are often maintained, curated, and administered by universities or other institutions. The Hybrid and Bronze categories have been combined as Other Journal-Based OA in this report because of their similar structure as journal-hosted types of OA that allow only conditional—and potentially revocable—OA.

The number of articles published annually in closed-access journals increased by 112% between 2003 and 2022 (Figure PBS-8). Over the same period, annual publishing of Green OA articles increased by 228%, while Other Journal-Based OA articles (Hybrid and Bronze OA) increased by 198%. Gold OA articles (which are published in OA journals with no restrictions) had the largest percentage growth, from 19,089 articles in 2003 to 991,805 articles in 2022, an increase of over 5,000%. Hence, although the majority (77%) of S&E articles in 2003 whose access status is known were published in closed-access journals, fewer than half (49%) were in closed-access journals in 2022.

To conclude this section, the findings of the output analysis reveal the growth in scientific publications over time, with upper-middle-income economies exhibiting particularly large percentage increases. Meanwhile, the distribution of publications across scientific fields shows that life sciences dominated in the United States, Europe, and Japan, whereas publications in engineering and computer sciences dominated in China and India. In OA, the dramatic growth of Gold OA publications and the steady growth of publications in other OA categories show an increased shift toward open science. However, OA can impede the dissemination of some scientific research. Publishing research as OA often requires authors to pay article processing fees, which may be prohibitive for scientists in less-developed nations or whose funders do not subsidize those fees.^{​Many publishers make their article processing charges (APCs) known publicly. For example, a list of Elsevier APCs can be found at https://www.elsevier.com/about/policies/pricing. Wiley APCs are at https://authorservices.wiley.com/author-resources/Journal-Authors/open-access/article-publication-charges.html. Springer Nature APCs are at https://www.springernature.com/gp/open-research/journals-books/journals.} The fees can be seen as shifting the costs of accessing research from readers and libraries to authors (Larivière and Sugimoto 2018).