2021 tables: Countries/territories - 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 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 82 natural-science journals through 2022, in 2023 64 health-science journals were added to the Index. The 146 journals in the Nature Index were selected on reputation by an independent panel of leading scientists in their fields.
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/.

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 annual tables.

*The change in adjusted Share accounts for the small annual variation in the total number of articles in Nature Index journals. Share values have been adjusted to 2022 levels to calculate the percentage change. For more information on the adjustment, please see the Adjusted metric explainer.