The Nature Index is a database of author affiliations and institutional relationships. The index tracks contributions to research articles published in 82 high-quality natural-science journals, chosen by an independent group of researchers.

The Nature Index provides absolute and fractional counts of article publication at the institutional and national level and, as such, is an indicator of global high-quality research output and collaboration. Data in the Nature Index are updated regularly, with the most recent 12 months made available under a Creative Commons licence at The database is compiled by Nature Portfolio.

Nature Index metrics

The Nature Index uses Count and Share to track research output. A country/territory or an institution is given a Count of 1 for each article that has at least one author from that country/territory or institution. This is the case regardless of the number of authors an article has, and it means that the same article can contribute to the Count of multiple countries/territories or institutions.

To glean a country’s, territory’s, region’s or an institution’s contribution to an article, and to ensure that they are not counted more than once, the Nature Index uses Share, a fractional count that takes into account the share of authorship on each article. The total Share available per article is 1, which is shared among all authors under the assumption that each contributed equally. For instance, an article with 10 authors means that each author receives a Share of 0.1. For authors who are affiliated with more than one institution, the author’s Share is split equally between each institution. The total Share for an institution is calculated by summing the Share for individual affiliated authors. The process is similar for countries/territories, although complicated by the fact that some institutions have overseas labs that will be counted towards host country/territory totals.

Adjusted Share accounts for the small annual variation in the total number of articles in the Nature Index journals. It is arrived at by calculating the percentage difference in the total number of articles in the Index in a given year relative to the number of articles in a base year and adjusting Share values to the base year levels.

The bilateral collaboration score (CS) between two institutions A+B is the sum of each of their Shares on the papers to which both have contributed. A bilateral collaboration can be between any two institutions or countries/territories co-authoring at least one article in the journals tracked by the Nature Index.

NATUREINDEX.COM users can search for specific institutions or countries and generate their own reports, ordered by Count or Share.

Each query will return a profile page that lists the country or institution’s recent outputs, from which it is possible to drill down for more information. Articles can be displayed by journal, and then by article. Research outputs are organized by subject area. The pages list the institution or country’s/territory’s top collaborators, as well as its relationship with other organizations. Users can track an institution’s performance over time, create their own indexes and export table data.

This supplement

Nature Index 2022 Biomedical sciences is based on the Nature Index database, covering articles published between 1 January 2015 and 31 December 2021. We have used the same methodology as in the Nature Index 2019 Biomedical sciences supplementfor defining relevant articles in biomedical sciences.

First, the 27 Nature Index journals that cover areas unrelated to biomedical research were removed from the analysis. The remaining 55 journals were then searched via the Dimensions from Digital Science database for articles in 1 or more of 29 fields of biomedical research. Articles were identified in the Nature Index for 26 of the 29 fields of research.

It is noted that we have defined biomedical sciences in the widest possible sense to encompass basic research relevant to the biomedical domain. Although every effort has been made to eliminate anomalies, some counts might be slightly high because the fields of research descriptors used to search Dimensions might pick up articles not directly related to biomedical research, for example, related to some aspects of microbiology and cell biology.

The tables in this supplement show leading countries/territories and institutions and their output in biomedical sciences in 2021, and the top rising countries/territories and institutions based on their change in output from 2015 to 2021 in the Nature Index database. Also included are the leading institution tables by four different sectors (academic, health care, government and NPO/NGO) as well as the leading institution pairs among international partnerships ranked by bilateral collaboration score.