SCIENCE & ENGINEERING INDICATORS

Article Counts: The number of peer-reviewed articles and conference papers indexed in the Scopus database that are produced by a given region, country, economy, or institutional sector. Articles coauthored by multiple countries or institutional sectors are counted in two ways: fractional or whole (see definitions in glossary).

BRIC: A grouping acronym referring to the countries of Brazil, Russia, India, and China.

Citations: Citations, generally at the end of each article, provide researchers with the list of the prior research relied upon for the article. Citations of S&E publications by other S&E publications provide an indication of the impact of publications and of the flow of knowledge or linkage between sectors or geographic locations.

Coauthorship: Coauthorship is when there is more than one author listed on a publication. Coauthorship measures collaboration across regions, countries, economies, and institutional sectors. Publication counts of coauthorship use whole counting, resulting in a full count assignment for each country or institutional sector contributing to the article. An article is considered an international coauthorship when there are institutional addresses for authors from two or more different countries. Table S5a-32 shows international coauthorship from 1996 to 2018.

European Union (EU): The EU is comprised of 28 member nations: Austria, Belgium, Bulgaria, Croatia, Cyprus, Czechia, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, the Netherlands, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, and the UK. Unless otherwise noted, Organisation for Economic Co-operation and Development data on the EU include all 28 nations. Bulgaria and Romania joined the EU in 2007 and Croatia joined in 2013—they are included in the EU grouping for all years analyzed in this report.

Fractional counting: Method of counting S&E publications in which credit for coauthored publications is divided among the collaborating institutions or countries based on the proportion of their participating authors. Fractional counting allocates the publication count by the proportion of each of the countries or institutional coauthors named on the article. Fractional counting enables the counts to sum up to the number of total articles. For example, if a paper was authored by two researchers from the University of Oslo, one from the University College London, and one from the University of Washington, half of the paper would be attributed to Norway and one quarter each to the UK and the United States when the fractions are calculated at the level of researchers. For this report, fractions were calculated at the level of researchers.

G7 countries: The Group of Seven (G7) is an international intergovernmental economic organization consisting of the seven largest International Monetary Fund members: Canada, France, Germany, Italy, Japan, the United Kingdom, and the United States.

Highly cited articles (HCA): An HCA score is not a perfect measure of influence, but it provides a rough indication of scientific impact (Waltman, Van Eck, and Wouters 2013). The first step is to create a dataset of the top 1% most-cited publications in each field and for each year. The HCA score for a country is the share of authors with institutional addresses within that country who have articles that are among the top 1% of the world’s highly cited articles, relative to all the articles ascribed to that country. The HCA score is indexed to 1, so that a country’s authors producing highly cited articles at the expected (i.e., global average) rate has an HCA score of 1—that is, 1% of the country’s articles are among the top 1% of the world’s highly cited articles. Countries with authors producing highly cited articles at greater than the expected rate have HCA scores greater than 1, and countries with authors producing influential articles at lower than the expected rate have HCA scores less than 1. For example, assume a world of two countries produced an output of 10,000 articles, with country x with authors producing 7,000 articles and country y with authors producing 3,000 articles. If both countries had the same influence in the citation records, then country x would have 70 highly cited articles and country y would have 30 highly cited articles in the top 100 most-cited articles in the world. Each country would have an HCA score of 1. The scores would be different if authors in one of the countries produced a higher proportion of the highly cited articles. For example, if authors in country y produced 50 of the most highly cited articles, then their HCA score would be 1.7, indicating that 1.7% of the articles of country y’s authors (50 out of 3,000) are among the top 1% of the world’s highly cited articles. For country x, the HCA score would be 0.7 (50 out of 7,000). The top 5% or 10% of highly cited articles can be analyzed in a similar fashion (Table S5a-35).

International collaboration index: The collaboration index is calculated as follows: ICxy = (Cxy/Cx)/(Cy/Cw), where ICxy is the index of collaboration between country x and country y, Cxy is the number of papers coauthored between country x and country y, Cx is the total number of international coauthorships by country x, Cy is the total number of international coauthorships by country y, and Cw is the total number of international coauthorships in the database. An index greater than 1.0 means that a country-country pair has a stronger-than-expected tendency to collaborate; an index less than 1.0 indicates a weaker-than-expected tendency to collaborate (Table S5a-34).

Specialization index: For any given scientific field, the specialization index indicates the extent to which a country focuses in that area. The index assesses the share of a country’s articles produced in a field of science relative to the world’s output in that field. The indicator is computed by comparing a country to the global average. In 2018, for instance, the United States produced about 143,000 of its 423,000 articles in health sciences (Table S5a-2 and Table S5a-10). By comparison, at the world level, only about 604,000 of 2,556,000 total articles were in health sciences (Table S5a-2 and Table S5a-10). Thus, the United States produces more articles in this area than expected, based on its total output and the world proportions. This indicator is indexed to 1.0, which represents the world level, meaning that a score above 1.0 shows that a country produced more of its publication output in the given scientific field than the global proportion, whereas a score below 1.0 shows that a country produced fewer articles in this field than the global average. When a country’s share of articles increases in one area, its share must decrease proportionately in other areas.

Whole counting: This measure (also called full or integer counting) assigns one count to each country or institutional sector involved in coauthoring the article, irrespective of their proportionate involvement in authorship. Whereas fractional counting aims to assess the proportionate contributions of countries or sectors, whole counting aims instead to assess the participation of countries or sectors. One result of this difference is that the sum of articles from countries or institutional sectors will exceed the total number of articles when whole counting is used. For the United States in 2018, there were 423,000 publications in the Scopus database as measured on a fractional-count basis and 549,000 as measured on a whole-count basis (Table S5a-2). In the full counting method, each paper is counted once for each entity listed in the address field. For example, if a paper was authored by two researchers from the University of Oslo, one from the University College London, and one from the University of Washington, the paper would be counted once for the University of Oslo, once for the University College London and once for the University of Washington. It would also be counted once for Norway, once for the UK, and once for the United States. When it comes to aggregating groups of institutions (e.g., research consortia) or groups of countries (e.g., the EU), double counting is avoided. This means that if authors from Croatia and France copublished a paper, this paper would be credited only once when counting papers for the EU, even though each country had been credited with one publication count.

BRIC: Brazil, Russia, India, and China

EU: European Union

G7: Group of Seven

HCA: highly cited articles

NSF: National Science Foundation

R&D: research and development

S&E: science and engineering

UK: United Kingdom