The influence of multidisciplinary mega-journals on the Journal Impact Factor: Discipline, country/region, category, JIF quartile, and journal

This study examines the significant impact of mega-journals (MJs) on the scholarly evaluation system, particularly their citation contributions and the increased impact factor scores of influenced entities. By analyzing seven MJs across multiple dimensions, including discipline, country/region, Web of Science (WoS) category, and JIF quartile, we used the Generalized Impact Factor (GIF) as a proxy for the Journal Impact Factor (JIF) and developed the Contribution to Impact Factor (CIF) metric to quantify MJs' contributions. Our findings indicate that MJs can increase the GIF of scholarly entities by up to 7.79 %, even in countries/regions with millions of citations. Notably, Computer Science, Information Systems received 14.21 % of its citations from MJs, the highest among 241 fields studied. These results highlight the potential for MJs to inflate citation-based metrics, posing challenges to the academic evaluation system. We recommend adaptive strategies to mitigate JIF inflation or the development of alternative metrics to ensure a fair evaluation system.