The Nature Index is a database that tracks institutions and countries/territories and their scientific output since its introduction in November, 2014.[1] Originally released with 64 natural-science journals, the Nature Index expanded to 82 natural-science journals in 2018, then added 64 health-science journals in 2023. Each year, Nature Index ranks the leading institutions (which can be companies, universities, government agencies, research institutes, or NGOs) and countries by the number of scientific articles and papers published in leading journals. This ranking can also be categorized by individual fields of research such as life sciences, chemistry, physics, or earth sciences, with different institutions leading in each. The Nature Index was conceived by Nature Portfolio. In total, more than 17,000 institutions are listed in the Nature Index.