Does C-score-based world ranking give an accurate account of the impact of research papers?

Published: 5 November 2023| Version 1 | DOI: 10.17632/f9gny773br.1
JOHN Philip


John Ioannidis et. al [1] created a publicly available database of top-cited scientists in the world (popularly known as the world's top 2% Scientist list of Stanford University). This database has generated a lot of interest among the scientific community, institutions, and media attention. Many institutions gave wide publicity to this ranking and prominently displayed the names of their colleagues in various media. Some institutions even rewarded those who made the list in different ways. At the same time, many people look at this list with skepticism, citing the approach and shortfalls in the formula used in the evaluation of the c-score. This database is based on a unique composite indicator (c-score), where standardized details such as citations, h-index, co-authorship adjusted hm-index, and citations to papers in different authorship positions are used[1]. The original database has been updated yearly since its creation in 2019[2-3]. Two separate databases are created based on career-long and, single recent year impact. Career-long data is based on the citations from 1996 to 2022, but the single-year database is based on citations received during the calendar year 2022. This database is created using Scopus data from Elsevier. The latest database is performed using all Scopus author profiles as of October 1, 2023[3]. The Scientists included in this database are classified into 22 scientific fields and 174 sub-fields. To address the concerns originating from the research community on the authenticity of this database, and to assess the strengths and weaknesses of the c-score-based evaluation, I have done a detailed analysis of the matrix parameters of the last 10-year Nobel laureates of Physics, chemistry, and medicine. In this analysis, the latest career-long database is used. In the case of Physics Nobel laureates, analysis is done with the details of Nobel laureates of the last 25 years. The details of the analysis are presented in this article. Though the article says the selection is based on the top 100,000 scientists by c-score (with and without self-citations) or a percentile rank of 2% or above in the sub-field, the actual career-based ranking list has 204644 names. In the career-based rank list, the person with the lowest h index in the list has an h22 of 2 (with an np6022 of 11 and total citations nc9622 of 835). There are 1155 authors with single-digit h22 index too. In the same list, the person with the lowest number of papers has an nc6022 of 2 (with nc9622 of 12128 and first and last publications in 1929 and 1966, respectively). The author with a minimum number of citations in the list has an nc9622 of 41 (h22 of 3). The c-score-based lowest rank holder in the list has a rank of 4809825 (nc9622 of 41, and h22 of 3). These results indicate aberrations in the ranking.


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Conclusions: Though most of the Nobel laureates (last 10 years) in science appear in the world ranking list based on the Scopus database, some of the Nobel laureates in physics and chemistry names did not appear (14 in physics during the last 25 years, and 3 in chemistry during the last 10 years). The total cites, h-index, and composite scores of most Nobel laureates were much lower as compared to the top 100 rankers in the list (most of them are nonawardees of the Nobel prize), yet their discoveries made the greatest benefit to humankind. The absence of some of the Nobel Laureates in the list indicates the incompleteness of the database used, persons belonging to industries, or other anomalies in the protocol used. The major anomalies are due to publications in Scopus non-indexed journals, extra benefits of first/last authors, problems in subject classification, and lack of standardization of citations with reference to the total number of publications, and papers with a large number of authors and review papers. The entry of many authors with single digit H index, the total number of citations (np6022) of 41, etc, in the list, indicate serious aberrations in the ranking methodology. Reference: [1] Ioannidis JPA, Baas J, Klavans R, Boyack KW. A standardized citation metrics author database annotated for scientific field. (2019) PLoS Biol, 17(8), art. no.: e3000384. pmid:31404057 [2] Ioannidis JPA, Boyack KW, Baas J (2020) Updated science-wide author databases of standardized citation indicators. PLoS Biol 18(10): e3000918. [3] John P.A. Ioannidis, October 2023 data-update for "Updated science-wide author databases of standardized citation indicators" 4 October 2023 (Version 6), DOI:10.17632/btchxktzyw.6


Indira Gandhi Centre for Atomic Research


Medicine, Chemistry, Physics, Basic Science