Stanford's Top 2% Scientists list is an emerging ranking that identifies scholars who are top-cited in their respective fields. It is based on an analysis of citation impact across multiple scientific fields and subfields using data from the Scopus database.
The ranking considers scholars who have published multiple highly cited papers. It evaluates the citation impact of their work using various metrics and takes into account both career-long citation impact and the impact in a single recent year. To determine the selection, the list includes the top 100,000 scientists based on their composite indicator (c-score, with and without self-citations) or a percentile rank of 2% or above in the sub-field.
Methodology
The ranking is achieved via a composite indicator (c-score) that is calculated based on 6 citation indicators as follows using Scopus data.
Figure 1. Formula to calculate the composite indicator (c-score) (Ioannidis, 2020)1
The Stanford approach combines all the above 6 indicators into a composite indicator that draws information from each and all of them. Among the 6 indicators, NC and H are associated with bulk impact, and Hm, NCS, NCSF and NCSFL are associated with author order and co-authorship-adjusted impact. (Ioannidis, 2016)2 The Stanford standardized citation metrics author database also presents metrics with and without self-citations and scientists are classified into 22 fields and 174 sub-fields according to the standard Science-Metric classification. (Ioannidis, 2019)3
If an author is not on the list, it is simply because the composite indicator value was not high enough to appear on the list. It does not mean that the author does not do good work. (Ioannidis, 2023)4
References:
1. Ioannidis, JP, Boyack, KW, & Baas, J (2020) Updated science-wide author databases of standardized citation indicators. PLoS Biol, 18(10): e3000918. https://doi.org/10.1371/journal.pbio.3000918
2. Ioannidis JP, Klavans R, Boyack KW (2016) Multiple Citation Indicators and Their Composite across Scientific Disciplines. PLoS Biol 14(7): e1002501. https://doi.org/10.1371/journal.pbio.1002501
3. Ioannidis JPA, Baas J, Klavans R, Boyack KW (2019) A standardized citation metrics author database annotated for scientific field. PLoS Biol 17(8): e3000384. https://doi.org/10.1371/journal.pbio.3000384
4. Ioannidis, J. P. (2023). October 2023 data-update for “Updated science-wide author databases of standardized citation indicators. Elsevier Data Repository, 6, 10-17632. https://doi.org/10.17632/btchxktzyw
Lists of Scientists
2023 Lists: https://elsevier.digitalcommonsdata.com/datasets/btchxktzyw/6
Past Lists (with Comparison): https://elsevier.digitalcommonsdata.com/datasets/compare/btchxktzyw?old=1&new=6
The 2% list also recognizes the influential contributions of CityU researchers across various scientific fields and subfields, highlighting their impact on the advancement of knowledge. Access the records in CityU Scholars.