Research Assessment Based on the Number of top Researchers

Bibliometrics provides accurate, cheap, and simple descriptions of research systems. The number of highly cited researchers reported by Clarivate Analytics (HCR) has been used for that purpose, assuming that a research system that employs many HCR will be more successful than others with fewer of them. Here, we study the use of the number of top researchers (TR) reported by Ioannidis, Boyack and Baas, J. in 2020 for research assessment at country level. Firstly, we validated the number of TR by correlation with the Ptop 5% indicator of the Leiden Ranking. After identifying the number of TR for the Leiden Ranking universities, we found a high correlation between the numbers of TR and top 5% papers when the data were aggregated at country level. Once the number of TR was validated, we constructed country rankings with the raw data and after normalization by the number of inhabitants or gross domestic product. The correlation between the numbers of TR and HCR is high, but with important divergences in countries with small numbers of HCR, which precludes the use of the number of HCR in many countries. The number of TR and HCR are approximately equivalent to the numbers of the top 5% and 0.05% of most cited papers, respectively. We conclude that the number of TR is a simple and reliable indicator of research success that can be used in much more countries than the number of HCR. It can also be used for institutions if affiliations are correctly identified