Who contributes most to scientific advancement within subject categories? Evidence from Italian academia

This study proposes a bibliometric approach to identify the academics making the largest cumulative contribution to national knowledge advancement within individual Web of Science subject categories (SC). Focusing on the Italian university system, we analyze the WoS-indexed publications of assistant, associate, and full professors during 2015–2024. For each scholar and SC, we calculate a Total Fractional Impact (TFI) indicator combining field-normalized citations, journal impact factors, and fractional contribution to coauthored publications. The scholar recording the highest TFI is identified as the national leading contributor in that SC, a position that we refer to as national subject-category leadership. The results reveal a highly concentrated structure of scientific contribution. Overall, the top-ranked scholar accounts on average for 3.2% of academic TFI in a category, while the top 1%, 2%, and 5% of contributors account on average for 21.4%, 30.6%, and 47.2%, respectively. Most leading contributors are senior full professors, although a few lower-rank academics emerge among the highest contributors. Women remain strongly underrepresented among national leading contributors. More than half of them emerge outside their prevailing SC, highlighting the relevance of cross-category and boundary-spanning research. The same scholar ranks first by both TFI and publication volume in only 37.9% of categories. The findings provide a micro-foundation for interpreting national scientific capabilities and offer evidence useful for research policy, university strategy, and talent management.