2021 Research Leaders: Leading countries/territories in physical sciences

Table criteria

Footnote

Each year, the Nature Index publishes tables based on counts of high-quality research outputs in the previous calendar year. Users please note:

1. The data behind the tables are based on a relatively small proportion of total research papers, they cover the natural sciences and health sciences only and outputs are non-normalized (that is, they don’t reflect the size of the country or institution, or its overall research output).
2. The Nature Index is one indicator of institutional research performance. The metrics of Count and Share used to order Nature Index listings are based on an institution’s or country’s publication output in 145 natural-science and health-science journals. The journals were selected on reputation by an independent panel of leading scientists in their fields. The list is reviewed periodically and journals may be removed or added. Articles from eLife were no longer included in the Nature Index from 2023 after the journal changed its publishing model.
3. Nature Index recognizes that many other factors must be taken into account when considering research quality and institutional performance; Nature Index metrics alone should not be used to assess institutions or individuals.
4. Nature Index data and methods are transparent and available under a creative commons licence at nature.com/nature-index/.
5. Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

The Nature Index database undergoes regular updating, corrections, adjustment of institutional hierarchies, and removal of retracted papers and thus the live website can differ from the frozen research leaders.