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 AI and robotics is based on both the Nature Index database and the Dimensions database from Digital Science, covering the Nature Index articles published between 1 January 2015 and 31 December 2021, as well as the Dimensions publications during the same period. Searches based on keyword, fields of research searches, and subject-related journals and proceedings have been used to extract AI and robotics publications in Dimensions. The extracted publication collection was confined to journal and conference papers. AI and robotics articles in the Nature Index are those extracted publications that are also in the Nature Index database.

Although the criteria used in publication searches for AI and robotics were conducted separately, the two resulting collections were combined and de-duplicated to form the full data set. The same methodology undertaken in the 2020 AI supplement was reused for extracting relevant AI publications. The search of publications in the additional field of robotics was achieved based on robotics-related keywords as well as specific journals and proceedings.

To determine the effectiveness of the use of exclusive and relevant keywords regarding robotics, manual checking was carried out on randomly selected publications from these searches. The results showed that false positives could reach ≥30%. Owing to the extensive incidental uses of ‘robotics’ found in these research papers, two changes were made. Relevant keywords related to robotics were refined and keyword searches were restricted to abstract and title only (instead of full text). The number of false positives from the random selection of articles was reduced to ≤10%. The number of robotics publications collected was around 74,000. Although some false negatives were inadvertently removed based on the tightened criteria, the robotics publications extracted using the current lists of exclusive and relevant keywords can provide a more focused view on the research field.

Exclusive keywords to robotics: ‘swarm robotics’, ‘swarm robot’, ‘soft robotics’, ‘soft robot’, ‘human-robot interaction’, ‘humanoid robot’, ‘robot learning’, ‘bio-inspired robotics’, ‘bio-inspired robot’, nanorobot*, telerobot*, ‘autonomous car’, ‘autonomous drone’.

Relevant keywords used in conjunction with robot* or autonom*: ‘multi-agent system’, ‘brain-computer interface’, ‘actuator’, ‘actuation’, ‘air muscle’, ‘artificial muscle’, ‘pneumatic muscle’, ‘mobile manipulator’, ‘dynamic balancing’, ‘man-machine system’, ‘simultaneous localization and mapping’, ‘simultaneous localisation and mapping’, ‘computer vision’, ‘symbolic reasoning’, ‘neuro-inspired computing’, teleoperat*.

robot* AND autonom* (where * represents a wildcard).

Finally, out of a total of 142 journals and proceedings found in Dimensions and identified to be robotics- or AI-and-robotics-focused, 67 of them had publications between 2015 and 2021. All articles from the list are automatically qualified as related to robotics.

The tables in this supplement show leading countries/territories and institutions in AI and robotics based on their total output between 2015 and 2021, and the top rising countries/territories and institutions in the field based on their change in output from 2015 to 2021 in the Nature Index database. Also included are the leading research organizations based on their output in the Dimensions database. Nature Index output is measured by article share (Share), and Dimensions output is measured by the number of publications. There are also leading institution tables by institution sector based on the Nature Index data and the leading institution pairs among international partnerships ranked by bilateral collaboration score.