Composite index (metrics) explained

The composite index or composite indicator (abbreviated as c-score)^[1] is a new numerical indicator that evaluates the quality of a scientist's research publications, regardless of the scientific field in which he/she operates.^{[2] [3] [4]}

It was initially introduced in 2016 by the Greek-American metascience researcher John Ioannidis at Stanford University and his collaborators, R. Klavans R. and K. Boyack.^[5] In 2019 an improved version of it^[6] was announced in the scientific journal PLOS Biology under the paper title "Updated science-wide author databases of standardized citation indicators".

Based on a metaresearch study by Ioannidis et al.,^[7] the new c-score is calculated by an algorithm that combines all scientific research fields and ranks research from the Scopus database across all research areas, even from those with lower citation density.

Such meta-research has analyzed and recently published, ultimately identifing the top 2% of the world's most influential scientists, in a unified way across each and every scientific sub-discipline.^{[8] [9]}

In general, the parameters that are taken into account and eventually determine the new composite-index (c-score) are the following ones:

• the total number of citations received (NC),
• the Hirsch index for the citations received (H),
• the Schreiber co-authorship adjusted Hm index for the citations received (Hm).
• the total number of citations received to papers for which the scientist is single author (NCS),
• the total number of citations received to papers for which the scientist is single or first author (NCSF), and
• the total number of citations received to papers for which the scientist is single, first, or last author (NCSFL).

Notes and References

1. van der Aalst . Wil M. P. . Hinz . Oliver . Weinhardt . Christof . Ranking the Ranker: How to Evaluate Institutions, Researchers, Journals, and Conferences? . Business & Information Systems Engineering . 65 . 6 . 2023 . 2363-7005 . 10.1007/s12599-023-00836-5 . 615–621. free . "An interesting approach to address some of these concerns was proposed by John Ioannidis and his colleagues (Ioannidis 2022; Ioannidis et al. 2016, 2019, 2020). They propose to use a composite indicator (called C-score), which is the sum of the standardized six log-transformed citation indicators (NC, H, Hm, NS, NSF, NSFL)"
2. Ioannidis . John P.A. . Klavans . Richard . Boyack . Kevin W. . Multiple Citation Indicators and Their Composite across Scientific Disciplines . PLOS Biology . Public Library of Science (PLoS) . 14 . 7 . 1 July 2016 . 1545-7885 . 10.1371/journal.pbio.1002501 . free . e1002501. 27367269 . 4930269 .
3. OLIVEIRA . LETICIA DE . REICHERT . FERNANDA . ZANDONÀ . EUGENIA . SOLETTI . ROSSANA C. . STANISCUASKI . FERNANDA . The 100,000 most influential scientists rank: the underrepresentation of Brazilian women in academia . Anais da Academia Brasileira de Ciências . FapUNIFESP (SciELO) . 93 . suppl 3 . 2021 . 1678-2690 . 10.1590/0001-3765202120201952 . 10183/233727 . free .
4. Koltun . Vladlen . Hafner . David . The h-index is no longer an effective correlate of scientific reputation . PLOS ONE . 16 . 6 . 2021-06-28 . 1932-6203 . 34181681 . 8238192 . 10.1371/journal.pone.0253397 . free . e0253397.
5. Ioannidis . John P.A. . Klavans . Richard . Boyack . Kevin W. . Multiple Citation Indicators and Their Composite across Scientific Disciplines . PLOS Biology . 14 . 7 . 2016-07-01 . 1545-7885 . 27367269 . 4930269 . 10.1371/journal.pbio.1002501 . free . e1002501.
6. Ioannidis . John P. A. . Boyack . Kevin W. . Baas . Jeroen . Updated science-wide author databases of standardized citation indicators . PLOS Biology . 18 . 10 . 2020-10-16 . 1545-7885 . 33064726 . 7567353 . 10.1371/journal.pbio.3000918 . free . e3000918.
7. Web site: Career Data 2019. 14 April 2024. data until 2019 (career data)
8. Web site: Top 2% of Scientists on Stanford List . Research and Innovation . 7 April 2021 . 14 April 2024. "A recently published list of the world’s top researchers has reinforced UNT's reputation as a world-class Tier One research university."
9. Web site: HTI Professors Listed as World's Top 2% Most-cited Scientists by Stanford University . Department of Health Technology and Informatics . 6 March 2024 . zh . 14 April 2024.