2. Excellence in scientific collaboration

International scientific collaboration, 2015
As a percentage of domestically authored documents, fractional counts

Source: OECD calculations based on Scopus Custom Data, Elsevier, Version 4.2017, July 2017. StatLink contains more data. See chapter notes.


Did you know?

In the last decade, coauthorship-based international scientific collaboration increased in 32 out of 35 OECD countries.

Over the 2005-15 period, international collaboration on scientific research intensified on a worldwide scale. China almost doubled its collaboration rate, albeit from a very low base. In 2015, Luxembourg, Iceland, Switzerland and Belgium were the OECD countries with the largest propensity to collaborate internationally.

Measures of scientific research collaboration and citation impact (a quality measure of scientific publishing) at the country level are positively correlated, especially for economies with lower levels of scientific production. These smaller economies attempt to overcome their limited scale by participating more intensively in global networks.

Joint analysis of excellence and leading authorship (i.e. affiliation of the leading author) provides further insight into the source of a country’s top-cited publications, as many are underpinned by international collaborations, often led by authors with foreign affiliations. The United States accounts for the largest share of top-cited publications led by domestic authors, followed by the Netherlands, Switzerland, Denmark and the United Kingdom. Some countries have high overall excellence rates thanks to the contribution of collaborative articles led by authors abroad.


International collaboration is defined as the number of domestically authored publications incorporating institutional affiliations of other countries or economies, as a percentage of all citable publications (articles, reviews and conference proceedings) attributed to authors with an affiliation in the reference economy.

International collaboration can apply to documents where the leading author has as first affiliation the reference economy and those where the lead author’s first reported affiliation is abroad. The leading author is identified from the identity of the designated corresponding author.

The normalised citation impact measure is the ratio between the average number of citations received by documents published by authors affiliated to an institution in a given economy and the world average of citations, over the same time period, by document type and subject area.

Scientific excellence indicates the amount (in percentage) of a unit’s scientific output that is included in the global set of the 10% most cited papers in their respective scientific fields. This indicator can be used in combination with data on the affiliation of the corresponding author – see Measurability box – to better describe the role of international collaboration as a driver of scientific excellence.

The citation impact of scientific production and the extent of international collaboration, 2012-16
As an index and percentage of all citable documents, based on fractional counts

Source: OECD calculations based on Scopus Custom Data, Elsevier, Version 4.2017, July 2017. StatLink contains more data. See chapter notes.


Top 10% most-cited documents and patterns of international collaboration, 2015
Domestic and foreign-led top cited, as a percentage of all documents, fractional counts

Source: OECD calculations based on Scopus Custom Data, Elsevier, Version 4.2017; and 2015 Scimago Journal Rank from the Scopus journal title list (accessed June 2017), July 2017. StatLink contains more data. See chapter notes



Publications are attributed to countries on the basis of their authors’ institutional affiliations. Whole and fractional counting methods have advantages and limitations, with the choice of a given method having potentially significant effects on reported figures, especially collaboration rates. Fractional counting methods have been used in this edition in order to avoid distortions caused by rising numbers of documents with very large affiliation lists which may inflate results.

A complementary approach is to investigate the leading author’s affiliation (Moya-Anegón et al., 2013). Attribution of leadership to the corresponding author can help inform the role of a given institution or country in collaboration activities. This leadership indicator shows the share of scientific output (in this case, highly cited documents) where a domestic author is listed as a corresponding author. The fractionalized documents attributed to any given country can be analysed according to whether the leading author is domestic, working in collaboration with the rest of the world or not, or foreign-based.