Two main criteria are used in the Nature Index to assess the performance of countries and research institutions: article count (total number of articles), and fractional count (the share of articles published in 82 reputable journals, selected by an independent group of researchers and reviewed by the Nature Index database.
The authors of the rankings emphasize that all participants are different from each other and the fractional count indicator cannot make allowance for all the distinguishing features of a specific organization. They also mention that there are a multitude of reasons why the results of the rankings can vary significantly from one year to another, but still highlight the value of the rankings as a database of the best and most in-demand natural sciences articles for the past year.
Russia takes 18th place in the overall rankings. Among the top ten Russian scientific institutions are National Research Center Kurchatov Institute, Joint Institute for Nuclear Research, and seven universities (Lomonosov Moscow State University, St. Petersburg State University, Moscow Institute of Physics and Technology, ITMO University, Skolkovo Institute of Science and Technology, Kazan Federal University, and the National University of Science and Technology “MISiS”). Only three universities out of these seven are members of the Project 5-100.
According to the Nature Index, in 2018 ITMO University has published 61 articles (article count) that are relevant to the rankings’ remit. Fractional count of all these publications amounted to 15.41. The majority of the articles (53) belong to the field of Physical Sciences, followed by Chemistry (18) and Life Sciences (4). It is worth mentioning that some articles can belong to several of these categories at the same time. More information is available here.