The scientific community is buzzing with the release of the August 2025 data update for the "Updated science-wide author databases of standardized citation indicators," commonly referred to as the list of the world's Top 2% most-cited scientists. This comprehensive database, compiled by a team led by Dr. John P.A. Ioannidis of Stanford University, addresses the widespread and often criticized misuse of citation metrics by providing a standardized, publicly available framework for assessing researcher impact.
This newest iteration, Version 8, is built upon the August 1, 2025, snapshot of Scopus data, making it one of the most up-to-date and rigorous scientific rankings globally. It offers two distinct views of influence: career-long impact, with data updated to the end of 2024, and single-recent year impact, focusing exclusively on citations received during the 2024 calendar year.
Methodology: Focusing on True Impact
The rigor of this ranking lies in its sophisticated methodology. Scientists are categorized into 22 broad scientific fields and 174 specific sub-fields, ensuring that comparisons are equitable and field-specific. The selection criteria include two main pathways to inclusion: ranking within the top 100,000 scientists globally based on the composite indicator (c-score), or achieving a percentile rank of 2% or above within their respective sub-field.
Crucially, the c-score is designed to be a more balanced measure than simple citation counts. It shifts the focus from research productivity (the number of publications) to genuine impact (citations). The c-score also incorporates several adjustments for factors such as co-authorship and the author’s position (e.g., single, first, or last author) to give a more accurate picture of an individual’s contribution.
In a move to enhance transparency, the database provides multiple metrics, including standard citations, h-index, and a co-authorship adjusted hm-index. Furthermore, the data offers separate calculations both with and without self-citations, and even integrates information on retracted papers (based on the Retraction Watch database) and citations to or from those retracted papers.
Implications and Use for the Scientific Community
The release of this database by Elsevier serves as an invaluable resource for institutions, funding bodies, and policymakers in evaluating global scientific talent. However, the authors emphasize that all citation metrics have limitations and their use must be "tempered and judicious," often referring users to the principles outlined in the Leiden Manifesto.
The project team also strongly advises listed scientists to ensure their underlying data in Scopus is accurate, as the published database is an archival version reflecting the Scopus profiles at the time of calculation and will not be individually changed upon request. Any corrections to affiliations or profiles must be directed to Scopus. This transparency and call for data integrity solidify the database's role as a benchmark for bibliometrics worldwide.