SCIENCE & ENGINEERING INDICATORS

Publication output reached 2.6 million in 2018 (Table 5a-1).^{​Publication output only includes those indexed in the Scopus database. The publication output discussion uses fractional counting, which credits coauthored publications according to the collaborating institutions or countries, 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 our data analysis, we employ filters 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 sidebar).} The high-income economies (the United States, Germany, Japan, and other similar countries) produced 56% of S&E articles in 2018, upper-middle-income economies (China, Russia, Brazil, and other similar countries) produced 34%, and lower-middle-income economies (India, Indonesia, Pakistan, and other similar countries) produced 9% (Figure 5a-1 and Table S5a-2).^{​This report uses the World Bank’s country income classifications issued on July 1, 2018. The World Bank updates the classifications each year on July 1. The World Bank income classifications are assigned using the gross national income per capita as measured in current U.S. dollars. This report uses the rankings. More information is available at https://datahelpdesk.worldbank.org/knowledgebase/articles/906519-world-bank-country-and-lending-groups.}

The last decade has seen a difference in the publication growth rates of middle- and high-income economies. The number of articles from upper-middle- and lower-middle-income economies combined grew 9% per year while the output of high-income countries grew 1% per year from 2008 to 2018 (Table S5a-2). The world’s average annual growth rate from 2008 to 2018 slowed to 4% compared to 6% for the 2000 to 2008 period (Table 5a-1 and Table S5a-2).^{​Year-to-year comparisons across Indicators reports are not possible because the bibliometric database constantly updates as new articles enter the database and additional information becomes available. The publication output trends and year-to-year comparisons are valid within all the 2020 Indicators reports because they all rely upon the June 2019 Scopus database download.}

The contribution to the world’s increasing publication output varies across countries and economies. Viewing each country’s or economy’s publication output as a share of the total global output shows that the historically large producers—United States, EU countries (combined), and Japan—have declining shares of the world’s increasing output since 2000 (Figure 5a-2 and Figure 5a-3). Meanwhile China and India have increased their share of the growing world output. China produced 5% of global output in 2000 and grew to 21% in 2018; India’s share rose from 2% to 5% during this period (Figure 5a-3). Among the 15 largest publication producers, countries with higher than average growth rates include South Korea (4%), Brazil (5%), China (8%), Russia (10%), India (11%), and Iran (11%) (Table 5a-1).

The U.S. annual publication growth rate of 1% fell below the world's average annual growth (4%) (Table 5a-1). EU countries that ranked among the world’s largest 15 producers had annual growth rates below the world average from 2008 to 2018: Italy (2%), Spain (2%), Germany (1%), the UK (1%), and France (0.0%) (Table 5a-1). The three largest contributors to the growth in the world’s publication output—from 1.8 million in 2008 to 2.6 million in 2018—were China (35%), the EU (12%), and India (11%) (Table 5a-1). The United States contributed 4% to the world’s publication research growth from 2008 to 2018.

In terms of the absolute number of publications, researchers in China and the United States produced the most S&E publications, producing 528,263 (21%) and 422,808 (17%) articles, respectively, of the 2.6 million world 2018 total (Table 5a-1). The next closest countries by research publication count were India (135,788), Germany (104,396), Japan (98,793), and the UK (97,681) (Table 5a-1). Nine other countries complete the list of the largest 15 countries by output: Russia, Italy, South Korea, France, Brazil, Canada, Spain, Australia, and Iran. Together, these 15 countries produced just over 75% of the world’s publication output in 2018 (Table 5a-1).^{​The trends are consistent whether using fractional counting as in Figure 5a-3 and Table 5a-1 or whole counting as in Table S5a-2. There is a slight difference between the United States and China when looking at the whole counting total production numbers. Using whole counting for 2018, the United States had 548,847 articles while China had 584,407. A whole counting measure allocates one full count to each country with an author contributing to the paper, rather than fractional counting where each country only receives a fraction. For example, if an article had four authors with two from the United States, one from China, and one from Brazil, the fractional scores would be 2/4 for the United States, 1/4 for China, and 1/4 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.} The top 15 producers of S&E articles have been stable over the last 10 years with the exception of Iran replacing Taiwan (Table 5a-1 and Table S5a-2).