The Nature Index includes only primary research articles published in the 145 selected journals tracked by the Nature Index.  They were selected based on reputation by panels of actively publishing scientists. The selections were made independently of Springer Nature, and validated by a subsequent survey of global researchers. Panelists and survey respondents were asked to list the journals they would most like to publish in and were asked not to consider the Journal Impact Factor. It is intended that the list of journals amounts to a reasonably consensual upper echelon of journals in the natural sciences and health sciences. It includes both multidisciplinary journals and some of the most highly selective journals within the main disciplines of the natural sciences and health sciences.

Each year, the Nature Index publishes league tables based on counts of high-quality research outputs in the previous calendar year. The 2023 tables are based on Nature Index data from 1 January 2022 to 31 December 2022.

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.