Researchers propose a new citation index that balances productivity and impact in academic publishing. The h-index of citations was introduced in 2005 by a physicist Jorge E. Hirsch. This index is defined simply as the maximum number h of an author’s published papers with at least h citations each. For example, h = 3 means that there are three papers with 3 or more citations, but if a fourth paper exists, it has fewer than four citations. The h-index has quickly gained popularity and is now widely used to measure productivity and impact in academic publishing. However, this index overlooks how highly each paper is cited, so to address this issue, Leo Egghe proposed in 2006 another citation index called g, which emphasizes top-cited papers, but at the same time neglects lower-cited ones. In the present work, Leonid Bogachev, Ruheyan Nuermaimaiti, and colleagues introduce a new citation index called “nu” (for the Greek letter ), which, they show mathematically, lies between the h-index and g-index, therefore providing a more balanced assessment of research impact by considering both productivity and citation quality. The authors caution, however, that citation metrics should complement rather than replace expert human evaluation and emphasize the need for a responsible practice in academic assessment.
PNAS Nexus
A citation index bridging Hirsch’s h and Egghe’s g
13-Jan-2026