The Nature Index is a database of author affiliation information collated from research articles published in an independently selected group of 82 high-quality science journals. It provides a close to real-time proxy of high-quality research output and collaboration at the institutional, national and regional level. The tables are based on a 12-month rolling window of data, which is updated monthly.

The Nature Index Annual Tables highlight the institutions and countries that dominated high quality research in the natural sciences as tracked by Nature Index. The rankings are based on an institution’s or country’s share of articles published in the 82 prestigious scientific journals selected by an independent panel of experts and tracked by the Nature Index database.

Each year, the Nature Index publishes league tables based on counts of high-quality research outputs in the previous calendar year. The 2020 tables are based on Nature Index data from 1 January 2019 to 31 December 2019.

The Nature Index includes primary research articles published in a group of high-quality science journals. The journals included in the Nature Index are selected by a panel of active scientists, independently of Nature Research. The selection process reflects researchers’ perceptions of journal quality, rather than using quantitative measures such as Impact Factor. It is intended that the list of journals amounts to a reasonably consensual upper echelon of journals in the natural sciences and includes both multidisciplinary journals and some of the most highly selective journals within the main disciplines of the natural sciences. The journals included in the Nature Index represent less than 4-5% of the journals covering natural sciences in the Web of Science (Clarivate Analytics) but account for close to 30% of total citations to natural science journals.

Article output is counted in two ways:

Count: where a Count of one is assigned to an institution or country if one or more authors of the research article are from that institution or country, regardless of how many co-authors there are from outside that institution or country.

Share: an institution’s or country/region’s Share takes into account the percentage of authors from that institution or country/region and the number of affiliated institutions per article. For calculation of the Share, all authors are considered to have contributed equally to the article. The maximum combined Share for any article is 1.0.

The ratio of Count to Share gives an indication of the degree to which an institution or country collaborates in its research. Broadly speaking, if the Count is a lot higher than the Share it indicates a high degree of external collaboration and dependency on external resources. If the Count is close in value to the Share it indicates limited collaboration with external researchers and a strong dependency on internal resources.