The H2G Index: A Novel Bibliometric Tool for Quantifying Mentorship Impact

Mentorship is a cornerstone of career development in academic and research settings, yet its impact is difficult to quantify. While traditional metrics, such as the h-index, measure individual research output, they fail to capture a senior researcher’s contribution to fostering the next generation of scientists. This study introduces the H2G index (“H-index of 2nd Generation researchers”), a bibliometric indicator proposed to address this gap. The H2G index estimates the indirect academic impact of a senior researcher from the h-indices of junior researchers who published as first authors on papers where the senior researcher appeared as last author. Under this authorship-based assumption, the last-author position is used as a proxy for mentorship. H2G is computed as the pseudomedian of the first authors’ h-indices, with a 95% confidence interval estimated by bootstrap resampling. In a manually inspected verification case, alternative data-curation approaches produced different point estimates, indicating sensitivity to upstream filtering choices. However, the corresponding comparisons did not yield statistically distinguishable H2G results, which supported the subsequent large-scale exploratory application based on the automatic unfiltered approach searching public databases (PubMed, Crossref, or OpenAlex with provided Python scripts). The H2G is proposed as a preliminary bibliometric approximation under explicit assumptions and limitations, not as a direct or validated measure of mentorship. Its potential use is supplementary and exploratory, and any institutional application would require external validation beyond the scope of the present work. Full details to replicate the results are provided in the Supplemental Material available at Harvard Dataverse (URL will be provided upon acceptance of the manuscript).