Composite index (metrics)

The composite index or composite indicator (abbreviated as c-score) 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.

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. In 2019 an improved version of it 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., 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.

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).