Scientific Quality Index: a composite size-independent metric compared with h-index for 480 medical researchers

The goal of this study was to measure the scientific output of 480 authorsleaders in 12 selected branches of medicine, using the Hirsch index (the h-index) and a newly proposed Scientific Quality Index (SQI). Data were collected from the Scopus database (2008-2017) and scientific output assessments, by the h-index were compared with those by SQI. SQI is calculated by the addition of the percentage of papers cited 10 times and the mean citation score (excluding self-citations and the citations of all co-authors for both). The following mean values of basic bibliometric parameters were obtained in the whole study group: the citation index: 7250 +/- 7817, the total number of papers: 187 +/- 104, the total number of cited papers: 175 +/- 101, the number of papers cited at least 10 times: 110 +/- 75, the percent of papers cited at least 10 times: 51 +/- 16, the mean number of citations per paper: 28 +/- 21. The mean value of the h-index was 33.2 +/- 16.1 and the mean SQI was 78.5 +/- 33.4. When ranked, according to the SQI, 279 (58.1%) authors decreased, while 199 (41.5%) improved their ranking position in comparison to the h-index scores. When correlated with the basic bibliometric parameters, SQI was less dependent on both the number of publications and the number of citations in comparison with the h-index. The SQI was strongly influenced by the mean citation score, followed by the percent of papers cited 10 times. The h-index correlated with the SQI, r=0.73, p<0.0001. Although strongly correlating, the h-index and the SQI reflect partially different aspects of individual scientific output. The SQI expresses mainly the qualitative features of scientific output, whereas the h-index is more influenced by its quantitative measures (the number of papers and the number of citations). Therefore, the SQI may be approached as an interesting alternative way for assessment of the scientific output of an individual researcher.